text:
Stankovic, Zoran and Barker, Alex and Russe, Maximilian and Geiger, Julia and Frydrychowicz, Alex and Langer, Mathias and Markl, Michael},
	month = dec,
	year = {2012},
	pages = {84}
}

@article{baltes_determination_2008,
	title = {Determination of peak velocity in stenotic areas: echocardiography versus k-t {SENSE} accelerated {MR} {Fourier} velocity encoding},
	volume = {246},
	issn = {1527-1315},
	shorttitle = {Determination of peak velocity in stenotic areas},
	doi = {10.1148/radiol.2453061366},
	abstract = {The study was approved by the local ethical committees, and informed consent from each participant was obtained. The purpose of the study was to compare accelerated magnetic resonance (MR) Fourier velocity encoding (FVE), MR phase-contrast velocity mapping, and echocardiography with respect to peak velocity determination in vascular or valvular stenoses. FVE data collection was accelerated by using the k-space and time sensitivity encoding, or k-t SENSE, technique. Peak velocities were evaluated in five healthy volunteers (one woman, four men; mean age, 28 years; range, 23-34 years), three patients with stenotic aortic valves (two women, one man; mean age, 67 years; range, 39-82 years), two patients with pulmonary valvular stenosis (a 14-year-old girl and a 36-year-old man), and two patients with aortic stenosis (two women aged 18 and 27 years). In volunteers, peak velocity determined by the different methods agreed well. In patients, similar peak velocities were obtained by using accelerated MR FVE and echocardiography, while phase-contrast MR imaging results tended to underestimate these values.},
	number = {1},
	journal = {Radiology},
	author = {Baltes, Christof and Hansen, Michael S and Tsao, Jeffrey and Kozerke, Sebastian and Rezavi, Reza and Pedersen, Erik M and Boesiger, Peter},
	month = jan,
	year = {2008},
	pmid = {17951351},
	keywords = {Adolescent, Adult, Aged, Aged, 80 and over, Aorta, Thoracic, Aortic Valve Stenosis, Arterial Occlusive Diseases, Blood Flow Velocity, Female, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Pulmonary Valve Stenosis},
	pages = {249--257}
}

@article{hautvast_automatic_2006,
	title = {Automatic contour propagation in cine cardiac magnetic resonance images},
	volume = {25},
	issn = {0278-0062},
	doi = {10.1109/TMI.2006.882124},
	abstract = {We have developed a method for automatic contour propagation in cine cardiac magnetic resonance images. The method consists of a new active contour model that tries to maintain a constant contour environment by matching gray values in profiles perpendicular to the contour. Consequently, the contours should maintain a constant position with respect to neighboring anatomical structures, such that the resulting contours reflect the preferences of the user. This is particularly important in cine cardiac magnetic resonance images because local image features do not describe the desired contours near the papillary muscle. The accuracy of the propagation result is influenced by several parameters. Because the optimal setting of these parameters is application dependent, we describe how to use full factorial experiments to optimize the parameter setting. We have applied our method to cine cardiac magnetic resonance image sequences from the long axis two-chamber view, the long axis four-chamber view, and the short axis view. We performed our optimization procedure for each contour in each view. Next, we performed an extensive clinical validation of our method on 69 short axis data sets and 38 long axis data sets. In the optimal parameter setting, our propagation method proved to be fast, robust, and accurate. The resulting cardiac contours are positioned within the interobserver ranges of manual segmentation. Consequently, the resulting contours can be used to accurately determine physiological parameters such as stroke volume and ejection fraction.},
	number = {11},
	journal = {IEEE transactions on medical imaging},
	author = {Hautvast, Gilion and Lobregt, Steven and Breeuwer, Marcel and Gerritsen, Frans},
	month = nov,
	year = {2006},
	pmid = {17117776},
	keywords = {Algorithms, Artificial Intelligence, Heart, Image Enhancement, Image Interpretation, Computer-Assisted, Imaging, Three-Dimensional, Information Storage and Retrieval, Magnetic Resonance Imaging, Cine, Pattern Recognition, Automated, Reproducibility of Results, Sensitivity and Specificity, Subtraction Technique},
	pages = {1472--1482}
}

@article{holmes_ovo_2009,
	title = {In ovo non-invasive quantification of the myocardial function and mass of chick embryos using magnetic resonance imaging},
	volume = {22},
	copyright = {Copyright © 2009 John Wiley \& Sons, Ltd.},
	issn = {1099-1492},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/nbm.1386/abstract},
	doi = {10.1002/nbm.1386},
	abstract = {Magnetic resonance imaging (MRI) has evolved as one of the major non-invasive tools to study healthy and diseased hearts in animal models, especially rodent models. Even though, the chick embryo has long been used as a model for cardiovascular research, MRI has not yet been used for in vivo cardiac studies. Part of the reason for this is the difficulty in monitoring the ECG and respiration of the chick embryo in the magnet for gating purposes. To overcome this complication, this paper presents the use of retrospective Cine MRI to measure the cardiac function of chick embryos in ovo for the first time, without the need for respiratory or cardiac gating. The resulting left ventricular functional parameters, from six chick embryos at 20 days of incubation, were (mean ± SD) EDV 69 ± 15 µL, ESV 31 ± 7 µL, SV 38 ± 9 µL and EF 54.5 ± 2\%. The use of retrospective Cine MRI at earlier stages of development is also discussed and difficulties have been highlighted. Copyright © 2009 John Wiley \& Sons, Ltd.},
	language = {en},
	number = {7},
	urldate = {2013-05-21},
	journal = {NMR in Biomedicine},
	author = {Holmes, William M. and McCabe, Christopher and Mullin, Jim M. and Condon, Barrie and Bain, Maureen M.},
	year = {2009},
	keywords = {Heart, MRI, chick, embryo, in ovo, myocardial function, retrospective},
	pages = {745--752}
}

@article{jung_improved_2007,
	title = {Improved k-t {BLAST} and k-t {SENSE} using {FOCUSS}},
	volume = {52},
	issn = {0031-9155},
	doi = {10.1088/0031-9155/52/11/018},
	abstract = {The dynamic MR imaging of time-varying objects, such as beating hearts or brain hemodynamics, requires a significant reduction of the data acquisition time without sacrificing spatial resolution. The classical approaches for this goal include parallel imaging, temporal filtering and their combinations. Recently, model-based reconstruction methods called k-t BLAST and k-t SENSE have been proposed which largely overcome the drawbacks of the conventional dynamic imaging methods without a priori knowledge of the spectral support. Another recent approach called k-t SPARSE also does not require exact knowledge of the spectral support. However, unlike k-t BLAST/SENSE, k-t SPARSE employs the so-called compressed sensing (CS) theory rather than using training. The main contribution of this paper is a new theory and algorithm that unifies the above mentioned approaches while overcoming their drawbacks. Specifically, we show that the celebrated k-t BLAST/SENSE are the special cases of our algorithm, which is asymptotically optimal from the CS theory perspective. Experimental results show that the new algorithm can successfully reconstruct a high resolution cardiac sequence and functional MRI data even from severely limited k-t samples, without incurring aliasing artifacts often observed in conventional methods.},
	number = {11},
	journal = {Physics in medicine and biology},
	author = {Jung, Hong and Ye, Jong Chul and Kim, Eung Yeop},
	month = jun,
	year = {2007},
	pmid = {17505098},
	keywords = {Algorithms, Artifacts, Brain, Fourier Analysis, Heart, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Magnetic Resonance Imaging, Cine, Models, Statistical, Myocardium, Normal Distribution, Time Factors},
	pages = {3201--3226}
}

@article{singh_coronary_2004,
	title = {Coronary artery imaging using three-dimensional breath-hold steady-state free precession with two-dimensional iterative partial fourier reconstruction},
	volume = {19},
	issn = {1053-1807},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/15112316},
	doi = {10.1002/jmri.20062},
	abstract = {PURPOSE

To assess the feasibility of using a two-dimensional partial Fourier (PF) reconstruction scheme to reduce the acquisition time of magnetic resonance imaging (MRI) of coronary arteries.

MATERIALS AND METHODS

Symmetric k-space data sets of coronary arteries were collected in seven volunteers using a three-dimensional breath-hold steady-state free precession (SSFP) sequence. Partial, asymmetric k-space data sets were generated by removing 25\% of the data in the readout direction and 25\% of the data in the phase encoding direction. The missing data were then estimated using a two-dimensional projection-onto-convex-sets (POCS) algorithm or filled with zeroes. Images were reconstructed from the full data set, the PF data set, and the zero-filled (ZF) data set, respectively. Coronary artery sharpness was evaluated quantitatively and qualitatively.

RESULTS

Coronary artery sharpness in PF images was comparable to that in full k-space images and significantly better than that in ZF images.

CONCLUSION

Two-dimensional POCS PF reconstruction is a potentially useful technique for reducing acquisition time or improving spatial resolution for breath-hold coronary MR angiography.},
	number = {5},
	urldate = {2012-08-21},
	journal = {Journal of magnetic resonance imaging: JMRI},
	author = {Singh, Ravi K and Deshpande, Vibhas S and Haacke, E Mark and Shea, Steven M and Xu, Yingbiao and McCarthy, Richard M and Carr, James and Li, Debiao},
	month = may,
	year = {2004},
	pmid = {15112316},
	keywords = {Adult, Coronary Vessels, Female, Fourier Analysis, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Angiography, Male, Middle Aged},
	pages = {645--649}
}

@article{ying_joint_2007,
	title = {Joint image reconstruction and sensitivity estimation in {SENSE} ({JSENSE})},
	volume = {57},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.21245/abstract},
	doi = {10.1002/mrm.21245},
	abstract = {Parallel magnetic resonance imaging (pMRI) using multichannel receiver coils has emerged as an effective tool to reduce imaging time in various applications. However, the issue of accurate estimation of coil sensitivities has not been fully addressed, which limits the level of speed enhancement achievable with the technology. The self-calibrating (SC) technique for sensitivity extraction has been well accepted, especially for dynamic imaging, and complements the common calibration technique that uses a separate scan. However, the existing method to extract the sensitivity information from the SC data is not accurate enough when the number of data is small, and thus erroneous sensitivities affect the reconstruction quality when they are directly applied to the reconstruction equation. This paper considers this problem of error propagation in the sequential procedure of sensitivity estimation followed by image reconstruction in existing methods, such as sensitivity encoding (SENSE) and simultaneous acquisition of spatial harmonics (SMASH), and reformulates the image reconstruction problem as a joint estimation of the coil sensitivities and the desired image, which is solved by an iterative optimization algorithm. The proposed method was tested on various data sets. The results from a set of in vivo data are shown to demonstrate the effectiveness of the proposed method, especially when a rather large net acceleration factor is used. Magn Reson Med 57:1196–1202, 2007. © 2007 Wiley-Liss, Inc.},
	language = {en},
	number = {6},
	urldate = {2011-04-12},
	journal = {Magnetic Resonance in Medicine},
	author = {Ying, Leslie and Sheng, Jinhua},
	month = jun,
	year = {2007},
	keywords = {SENSE, joint estimation, self calibration, sensitivity estimation, variable density acquisition},
	pages = {1196--1202}
}

@article{odille_generalized_2008-1,
	title = {Generalized {MRI} reconstruction including elastic physiological motion and coil sensitivity encoding},
	volume = {59},
	copyright = {Copyright © 2008 Wiley-Liss, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.21520/abstract},
	doi = {10.1002/mrm.21520},
	abstract = {This article describes a general framework for multiple coil MRI reconstruction in the presence of elastic physiological motion. On the assumption that motion is known or can be predicted, it is shown that the reconstruction problem is equivalent to solving an integral equation—known in the literature as a Fredholm equation of the first kind—with a generalized kernel comprising Fourier and coil sensitivity encoding, modified by physiological motion information. Numerical solutions are found using an iterative linear system solver. The different steps in the numerical resolution are discussed, in particular it is shown how over-determination can be used to improve the conditioning of the generalized encoding operator. Practical implementation requires prior knowledge of displacement fields, so a model of patient motion is described which allows elastic displacements to be predicted from various input signals (e.g., respiratory belts, ECG, navigator echoes), after a free-breathing calibration scan. Practical implementation was demonstrated with a moving phantom setup and in two free-breathing healthy subjects, with images from the thoracic-abdominal region. Results show that the method effectively suppresses the motion blurring/ghosting artifacts, and that scan repetitions can be used as a source of over-determination to improve the reconstruction. Magn Reson Med, 2008. © 2008 Wiley-Liss, Inc.},
	language = {en},
	number = {6},
	urldate = {2012-10-02},
	journal = {Magnetic Resonance in Medicine},
	author = {Odille, Freddy and Cîndea, Nicolae and Mandry, Damien and Pasquier, Cédric and Vuissoz, Pierre-André and Felblinger, Jacques},
	year = {2008},
	keywords = {Fredholm equation, magnetic resonance, motion correction, parallel imaging, reconstruction},
	pages = {1401--1411}
}

@article{manniesing_robust_2010,
	title = {Robust {CTA} lumen segmentation of the atherosclerotic carotid artery bifurcation in a large patient population},
	volume = {14},
	issn = {1361-8423},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/20605737},
	doi = {10.1016/j.media.2010.05.001},
	abstract = {We propose and validate a semi-automatic method for lumen segmentation of the carotid bifurcation in computed tomography angiography (CTA). First, the central vessel axis is obtained using path tracking between three user-defined points. Second, starting from this path, the segmentation is automatically obtained using a level set. The cost and speed functions for path tracking and segmentation make use of intensity and homogeneity slice-based image features. The method is validated on a large data set of 234 carotid bifurcations of 129 ischemic stroke patients with atherosclerotic disease. The results are compared to manually obtained lumen segmentations. Parameter optimization is carried out on a subset of 30 representative carotid bifurcations. With the optimized parameter settings the method successfully tracked the central vessel paths in 201 of the remaining 204 bifurcations (99\%) which were not part of the training set. Comparison with manually drawn segmentations shows that the average overlap between the method and observers is similar (for the inter-observer set the results were 92\% vs. 87\% and for the intra-observer set 94\% vs. 94\%). Therefore the method has potential to replace the manual procedure of lumen segmentation of the atherosclerotic bifurcation in CTA.},
	number = {6},
	urldate = {2011-01-03},
	journal = {Medical Image Analysis},
	author = {Manniesing, Rashindra and Schaap, Michiel and Rozie, Sietske and Hameeteman, Reinhard and Vukadinovic, Danijela and van der Lugt, Aad and Niessen, Wiro},
	month = dec,
	year = {2010},
	pmid = {20605737},
	keywords = {Algorithms, Angiography, Atherosclerosis, Carotid Artery Diseases, Female, Humans, Male, Pattern Recognition, Automated, Radiographic Image Enhancement, Radiographic Image Interpretation, Computer-Assisted, Reproducibility of Results, Sensitivity and Specificity, Tomography, X-Ray Computed},
	pages = {759--769}
}

@article{meyer_simultaneous_1990,
	title = {Simultaneous spatial and spectral selective excitation},
	volume = {15},
	issn = {0740-3194},
	abstract = {Using a k-space interpretation of small-tip excitation, a single excitation pulse has been designed that is simultaneously selective in space and resonant frequency. An analytic expression for the response of this pulse has been derived. The pulse has been implemented on a 1.5-T imaging system. The pulse has been applied to a rapid gradient-echo imaging sequence that forms both water and fat images within a breath-holding interval. These rapid images are free of the chemical shift artifacts at organ boundaries that typically afflict conventional rapid images. The pulse can be applied to a variety of other sequences, such as multislice water/fat sequences and rapid k-space scanning sequences.},
	number = {2},
	journal = {Magnetic resonance in medicine: official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Meyer, C H and Pauly, J M and Macovski, A and Nishimura, D G},
	month = aug,
	year = {1990},
	pmid = {2392053},
	keywords = {Adipose Tissue, Body Water, Computer Simulation, Fourier Analysis, Humans, Image Enhancement, Magnetic Resonance Imaging, Mathematics, Models, Biological},
	pages = {287--304}
}

@article{weiger_motion-adapted_1997,
	title = {Motion-adapted gating based on k-space weighting for reduction of respiratory motion artifacts},
	volume = {38},
	copyright = {Copyright © 1997 Wiley-Liss, Inc., A Wiley Company},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com.gate2.inist.fr/doi/10.1002/mrm.1910380223/abstract},
	doi = {10.1002/mrm.1910380223},
	abstract = {A new modified type of gating is presented that shows the ability to reduce the total scan time with almost conserved image quality compared with conventional gating. This new motion-adapted gating approach is based on a k-space-dependent gating threshold function. MR data acquired are only accepted if the motion-induced displacements measured from a reference position are below the chosen gating threshold function. During the MR measurement the scanner analyses respiratory motion decides in real-time which data in k-space could be measured according to the gating threshold function and performs data acquisition. In the present paper the approach will be described and discussed. Simulations based on in vivo data and initial in vivo experiments are presented to compare different variants of the new approach mutually and to the conventional technique. The analysis given is focused on spin warp type sequences, which are the best candidates for this approach.},
	language = {en},
	number = {2},
	urldate = {2012-08-16},
	journal = {Magnetic Resonance in Medicine},
	author = {Weiger, Markus and Börnert, Peter and Proksa, Roland and Schäffter, Tobias and Haase, Axel},
	year = {1997},
	keywords = {MRI, Real-time, navigator gating, respiratory motion},
	pages = {322--333}
}

@article{spincemaille_kalman_2008,
	title = {Kalman filtering for real-time navigator processing},
	volume = {60},
	issn = {0740-3194},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/18581354},
	doi = {10.1002/mrm.21649},
	abstract = {Navigator echoes are used in high-resolution cardiac MRI for tracking physiological motion to suppress motion artifacts. Alternatives to the conventional diaphragm navigator such as the cardiac fat navigator and the k-space center signal (self-navigator) were developed to monitor heart motion directly. These navigator data can be noisy or may contain undesirable frequency components. Real-time filtering of navigator data without delay, as opposed to the previously used retrospective frequency band filtering, is required for effective prospective navigator gating. One of the commonly used real-time filtering techniques is the Kalman filter, which adaptively estimates motion and suppresses measurement noise by using Bayesian statistics and a motion model. The Kalman filter is investigated in this work to filter noise and distinguish cardiac and respiratory components in navigator data. Preliminary imaging data demonstrate the feasibility of real-time Kalman filtering for prospective respiratory self-gating in CINE cardiac MRI.},
	number = {1},
	urldate = {2011-01-12},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Spincemaille, Pascal and Nguyen, Thanh D and Prince, Martin R and Wang, Yi},
	month = jul,
	year = {2008},
	pmid = {18581354},
	keywords = {Artifacts, Bayes Theorem, Computer Simulation, Heart, Humans, Magnetic Resonance Imaging, Cine, Motion, Respiratory Physiological Phenomena},
	pages = {158--168}
}

@article{ries_real-time_2010-1,
	title = {Real-time 3D target tracking in {MRI} guided focused ultrasound ablations in moving tissues},
	volume = {64},
	issn = {1522-2594},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/20878763},
	doi = {10.1002/mrm.22548},
	abstract = {Magnetic resonance imaging-guided high intensity focused ultrasound is a promising method for the noninvasive ablation of pathological tissue in abdominal organs such as liver and kidney. Due to the high perfusion rates of these organs, sustained sonications are required to achieve a sufficiently high temperature elevation to induce necrosis. However, the constant displacement of the target due to the respiratory cycle render continuous ablations challenging, since dynamic repositioning of the focal point is required. This study demonstrates subsecond 3D high intensity focused ultrasound-beam steering under magnetic resonance-guidance for the real-time compensation of respiratory motion. The target is observed in 3D space by coupling rapid 2D magnetic resonance-imaging with prospective slice tracking based on pencil-beam navigator echoes. The magnetic resonance-data is processed in real-time by a computationally efficient reconstruction pipeline, which provides the position, the temperature and the thermal dose on-the-fly, and which feeds corrections into the high intensity focused ultrasound-ablator. The effect of the residual update latency is reduced by using a 3D Kalman-predictor for trajectory anticipation. The suggested method is characterized with phantom experiments and verified in vivo on porcine kidney. The results show that for update frequencies of more than 10 Hz and latencies of less then 114 msec, temperature elevations can be achieved, which are comparable to static experiments.},
	number = {6},
	urldate = {2011-01-03},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Ries, Mario and de Senneville, Baudouin Denis and Roujol, Sébastien and Berber, Yasmina and Quesson, Bruno and Moonen, Chrit},
	month = dec,
	year = {2010},
	pmid = {20878763},
	pages = {1704--1712}
}

@article{lauterbur_image_1973,
	title = {Image formation by induced local interactions: examples employing nuclear magnetic resonance},
	volume = {242},
	shorttitle = {Image formation by induced local interactions},
	number = {5394},
	journal = {Nature},
	author = {Lauterbur, P. C},
	year = {1973},
	pages = {190--191}
}

@article{giese_analysis_2012,
	title = {Analysis and correction of background velocity offsets in phase‐contrast flow measurements using magnetic field monitoring},
	volume = {67},
	copyright = {Copyright © 2011 Wiley Periodicals, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.23111/full},
	doi = {10.1002/mrm.23111},
	abstract = {The value of phase-contrast magnetic resonance imaging for quantifying tissue motion and blood flow has been long recognized. However, the sensitivity of the method to system imperfections can lead to inaccuracies limiting its clinical acceptance. A key source of error relates to eddy current-induced phase fluctuations, which can offset the measured object velocity significantly. A higher-order dynamic field camera was used to study the spatiotemporal evolution of background phases in cine phase-contrast measurements. It is demonstrated that eddy current-induced offsets in phase-difference data are present up to the second spatial order. Oscillatory temporal behaviors of offsets in the kHz range suggest mechanical resonances of the MR system to be non-negligible in phase-contrast imaging. By careful selection of the echo time, their impact can be significantly reduced. When applying field monitoring data for correcting eddy current and mechanically induced velocity offsets, errors decrease to less than 0.5\% of the maximum velocity for various sequence settings proving the robustness of the correction approach. In vivo feasibility is demonstrated for aortic and pulmonary flow measurements in five healthy subjects. Using field monitoring data, mean error in stroke volume was reduced from 10\% to below 3\%. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.},
	language = {en},
	number = {5},
	urldate = {2012-04-23},
	journal = {Magnetic Resonance in Medicine},
	author = {Giese, Daniel and Haeberlin, Maximilian and Barmet, Christoph and Pruessmann, Klaas P and Schaeffter, Tobias and Kozerke, Sebastian},
	month = may,
	year = {2012},
	keywords = {background velocity offsets, flow measurements, magnetic field monitoring, phase‐contrast imaging},
	pages = {1294--1302}
}

@article{cusack_new_2002,
	title = {New {Robust} 3-{D} {Phase} {Unwrapping} {Algorithms}: {Application} to {Magnetic} {Field} {Mapping} and {Undistorting} {Echoplanar} {Images}},
	volume = {16},
	issn = {1053-8119},
	shorttitle = {New {Robust} 3-{D} {Phase} {Unwrapping} {Algorithms}},
	url = {http://www.sciencedirect.com/science/article/pii/S105381190291092X},
	doi = {10.1006/nimg.2002.1092},
	abstract = {The phase, as well as the magnitude, of MRI images can carry useful information. It may be used to encode flow or temperature, or to map the magnetic field for the undistorting of EPIs and automated shimming. In all cases, we measure the extra spin given to nuclei. Unfortunately, we can only measure the final phase of the spins: the rotation is wrapped into the range [−π, +π], and to obtain a measure of the parameter of interest the missing multiples of 2π must be replaced—a process known as phase unwrapping. While simple in principle, standard phase unwrapping algorithms fail catastrophically in the presence of even small amounts of noise. Here we present a new algorithm for robust three-dimensional phase unwrapping, in which unwrapping is guided, so that it initially works on less noisy regions. We test the algorithm on simulated phase data, and on maps of magnetic field, which were then used to successfully undistort EPI images. The unwrapping algorithm could be directly applied to other kinds of phase data.},
	number = {3, Part A},
	urldate = {2014-05-20},
	journal = {NeuroImage},
	author = {Cusack, R. and Papadakis, N.},
	month = jul,
	year = {2002},
	pages = {754--764}
}

@article{ferreira_cardiovascular_2013,
	title = {Cardiovascular magnetic resonance artefacts},
	volume = {15},
	copyright = {2013 Ferreira et al.; licensee BioMed Central Ltd.},
	issn = {1532-429X},
	url = {http://jcmr-online.com/content/15/1/41/abstract},
	doi = {10.1186/1532-429X-15-41},
	abstract = {The multitude of applications offered by CMR make it an increasing popular modality to study the heart and the surrounding vessels. Nevertheless the anatomical complexity of the chest, together with cardiac and respiratory motion, and the fast flowing blood, present many challenges which can possibly translate into imaging artefacts. The literature is wide in terms of papers describing specific MR artefacts in great technical detail. In this review we attempt to summarise, in a language accessible to a clinical readership, some of the most common artefacts found in CMR applications. It begins with an introduction of the most common pulse sequences, and imaging techniques, followed by a brief section on typical cardiovascular applications. This leads to the main section on common CMR artefacts with examples, a short description of the mechanisms behind them, and possible solutions.
PMID: 23697969},
	language = {en},
	number = {1},
	urldate = {2014-01-26},
	journal = {Journal of Cardiovascular Magnetic Resonance},
	author = {Ferreira, Pedro F. and Gatehouse, Peter D. and Mohiaddin, Raad H. and Firmin, David N.},
	month = may,
	year = {2013},
	pmid = {23697969},
	pages = {41},
	file = {Full Text PDF:/Users/cmey/Zotero/storage/Q32ZK2EF/Ferreira et al. - 2013 - Cardiovascular magnetic resonance artefacts.pdf:application/pdf;Snapshot:/Users/cmey/Zotero/storage/D74IT7GV/41.html:text/html}
}

@article{pertschy_partial_2006,
	title = {Partial k-space sampling with zero filling used with phase-contrast flow measurements: in vivo and in vitro validation},
	volume = {178},
	issn = {1438-9029},
	shorttitle = {[{Partial} k-space sampling with zero filling used with phase-contrast flow measurements},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/16817124},
	doi = {10.1055/s-2006-926793},
	abstract = {PURPOSE

To validate the technique of partial k-space sampling and zero filling with phase-contrast flow measurements as compared to measurements with full k-space sampling.

MATERIALS AND METHODS

In vitro: A laminar flow phantom was utilized to evaluate the effect of partial k-space sampling on the accuracy, precision and signal-to-noise ratio of phase-contrast flow measurements. In vivo: The effect of partial k-space sampling on the quantification of cardiac output (n = 40 patients) and the duration of the scan were evaluated in the ascending aorta (n = 37) and pulmonary trunk (n = 34) in a prospective study.

RESULTS

Partial k-space sampling resulted in an increase in the SNR by 2 \% in vitro. The precision was altered by less than 1 \%. Flow volumes were systematically overestimated by 3.5 \%. No significant differences were found in the in vivo measurements of cardiac output. The scan duration was reduced by 34 \% by utilizing partial k-space sampling.

CONCLUSION

Partial k-space sampling can be used to reduce scan time without a significant decrease in the accuracy or precision of phase-contrast flow measurements in large arteries.},
	number = {7},
	urldate = {2012-08-30},
	journal = {RöFo: Fortschritte auf dem Gebiete der Röntgenstrahlen und der Nuklearmedizin},
	author = {Pertschy, S and Meyer, G P and Waalkes, S and Doeker, R and Koshedub, R and Noeske, R and Galanski, M and Lotz, J},
	month = jul,
	year = {2006},
	pmid = {16817124},
	keywords = {Arteries, Blood Flow Velocity, Cardiac Output, Humans, Image Enhancement, Image Interpretation, Computer-Assisted, Magnetic Resonance Imaging, Phantoms, Imaging, Reproducibility of Results, Rheology, Sample Size, Sensitivity and Specificity, Signal Processing, Computer-Assisted},
	pages = {713--720}
}

@article{schar_cardiac_2004,
	title = {Cardiac {SSFP} imaging at 3 {Tesla}},
	volume = {51},
	copyright = {Copyright © 2004 Wiley-Liss, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.20024/abstract},
	doi = {10.1002/mrm.20024},
	abstract = {Balanced steady-state free precession (SSFP) techniques provide excellent contrast between myocardium and blood at a high signal-to-noise ratio (SNR). Hence, SSFP imaging has become the method of choice for assessing cardiac function at 1.5T. The expected improvement in SNR at higher field strength prompted us to implement SSFP at 3.0T. In this work, an optimized sequence protocol for cardiac SSFP imaging at 3.0T is derived, taking into account several partly adverse effects at higher field, such as increased field inhomogeneities, longer T1, and power deposition limitations. SSFP contrast is established by optimizing the maximum amplitude of the radiofrequency (RF) field strength for shortest TR, as well as by localized linear or second-order shimming and local optimization of the resonance frequency. Given the increased SNR, sensitivity encoding (SENSE) can be employed to shorten breath-hold times. Short-axis, long-axis, and four-chamber cine views obtained in healthy adult subjects are presented, and three different types of artifacts are discussed along with potential methods for reducing them. Magn Reson Med 51:799–806, 2004. © 2004 Wiley-Liss, Inc.},
	language = {en},
	number = {4},
	urldate = {2014-09-25},
	journal = {Magnetic Resonance in Medicine},
	author = {Schär, Michael and Kozerke, Sebastian and Fischer, Stefan E. and Boesiger, Peter},
	month = apr,
	year = {2004},
	keywords = {3 Tesla, SENSE, higher-order shimming, localized frequency determination, localized shimming, steady-state free precession (SSFP)},
	pages = {799--806}
}

@article{millman_nuclear_1938,
	title = {On the {Nuclear} {Moments} of {Indium}},
	volume = {53},
	url = {http://link.aps.org/doi/10.1103/PhysRev.53.384},
	doi = {10.1103/PhysRev.53.384},
	abstract = {The atomic beam method of zero moments has been applied to measure the nuclear spin, the h.f.s. Δν of the normal 2P1/2 state and the absolute magnetic moment of In 115. The spin was found to be 9/2 and the Δν=0.381 cm-1 in agreement with spectroscopic results. The resolving power which was attained was sufficiently high to allow a measurement of the fine structure of the zero moment peaks. From the separation of the two m=-3 peaks and the diamagnetic susceptibility, we calculate the moment of indium 115 to be 6.40±0.20 nuclear magnetons. From the theory of this effect which is given below, it is clear that this value does not depend on any assumption with regard to the interaction between the nuclear spin and the electron configuration. Peaks arising from the metastable 2P3/2 state, lying 2212.6 cm-1 above the 2P1/2 state were found. The intensity of these peaks is in good agreement with what is expected from quantum statistics. Their exact location will permit an evaluation of the nuclear quadrupole moment.},
	number = {5},
	urldate = {2011-03-08},
	journal = {Physical Review},
	author = {Millman, S. and Rabi, I. I. and Zacharias, J. R.},
	month = mar,
	year = {1938},
	pages = {384}
}

@inproceedings{meyer_mesure_2012-1,
	address = {Marseille},
	title = {Mesure de débit en respiration libe en {IRM} {CINE} à contraste de phase corrigée en mouvement},
	booktitle = {{SFRMBM}},
	author = {Meyer, Christophe and Vuissoz, Pierre-André and Mandry, Damien and Felblinger, Jacques},
	year = {2012}
}

@article{uecker_image_2008-1,
	title = {Image reconstruction by regularized nonlinear inversion—{Joint} estimation of coil sensitivities and image content},
	volume = {60},
	copyright = {Copyright © 2008 Wiley-Liss, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.21691/abstract},
	doi = {10.1002/mrm.21691},
	abstract = {The use of parallel imaging for scan time reduction in MRI faces problems with image degradation when using GRAPPA or SENSE for high acceleration factors. Although an inherent loss of SNR in parallel MRI is inevitable due to the reduced measurement time, the sensitivity to image artifacts that result from severe undersampling can be ameliorated by alternative reconstruction methods. While the introduction of GRAPPA and SENSE extended MRI reconstructions from a simple unitary transformation (Fourier transform) to the inversion of an ill-conditioned linear system, the next logical step is the use of a nonlinear inversion. Here, a respective algorithm based on a Newton-type method with appropriate regularization terms is demonstrated to improve the performance of autocalibrating parallel MRI—mainly due to a better estimation of the coil sensitivity profiles. The approach yields images with considerably reduced artifacts for high acceleration factors and/or a low number of reference lines. Magn Reson Med, 2008. © 2008 Wiley-Liss, Inc.},
	language = {en},
	number = {3},
	urldate = {2013-01-18},
	journal = {Magnetic Resonance in Medicine},
	author = {Uecker, Martin and Hohage, Thorsten and Block, Kai Tobias and Frahm, Jens},
	year = {2008},
	keywords = {inverse problems, iterative reconstruction, nonlinear inversion, parallel imaging},
	pages = {674--682}
}

@article{juchem_1h-mrs_2007,
	title = {1H-{MRS} of the macaque monkey primary visual cortex at 7 {T}: strategies and pitfalls of shimming at the brain surface},
	volume = {25},
	issn = {0730-725X},
	shorttitle = {1H-{MRS} of the macaque monkey primary visual cortex at 7 {T}},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/17467220},
	doi = {10.1016/j.mri.2007.03.008},
	abstract = {Magnetic resonance spectroscopy (MRS) is ideally suited for physiology-neurochemistry experiments with the living brain and particularly for studies on the primary visual cortex (striate cortex or area V1). Yet, the highly convoluted form of the human V1 has thus far prevented the performance of MRS investigations that are spatially confined within the gray matter of this area. Typically, these studies are compromised by partial volume contaminations originating from white matter tissue, cerebrospinal fluid and other cortical areas. In this study, was exploited the relative flatness of V1 in macaques to enable single-voxel 1H-MRS from a small volume (5 x 1.6 x 5 mm3, 40 microl) that was entirely confined within the V1 gray matter of anesthetized monkeys. Linewidths of 13.5+/-1.9 Hz and 13.0+/-1.3 Hz for water and creatine, respectively, were achieved with a two-step shimming strategy for voxels at the brain surface. The quality of the obtained results paves the way for further neuroscientific research, including studies on the cortical microcircuits and the dynamic longitudinal changes occurring during cortical reorganization and plasticity.},
	number = {6},
	urldate = {2011-01-03},
	journal = {Magnetic Resonance Imaging},
	author = {Juchem, Christoph and Logothetis, Nikos K and Pfeuffer, Josef},
	month = jul,
	year = {2007},
	pmid = {17467220},
	keywords = {Animals, Brain, Brain Mapping, Cerebrovascular Circulation, Electromagnetic Fields, Image Enhancement, Image Processing, Computer-Assisted, Macaca, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Protons, Reproducibility of Results, Sensitivity and Specificity, Visual Cortex},
	pages = {902--912}
}

@inproceedings{morrison_multichannel_2007,
	title = {{MULTICHANNEL} {ESTIMATION} {OF} {COIL} {SENSITIVITIES} {IN} {PARALLEL} {MRI}},
	doi = {10.1109/ISBI.2007.356802},
	abstract = {We consider the problem of estimating receiver coil sensitivity functions in parallel MRI. By exploiting the multichannel nature of the problem, where multiple acquisitions of the same image function are obtained with different sensitivity weightings, we obtain a subspace-based framework for directly solving for the sensitivity functions. The proposed approach does not rely on the sum-of-squares assumption used in existing estimation schemes; this assumption tends to be violated towards the center of the image, thus leading to errors in the sensitivity estimates. Our approach eliminates this problem, producing superior sensitivity estimates in comparison to the sum-of-squares technique. In addition, the proposed restoration procedure is non-iterative, computationally efficient, and applicable both to cases where pilot scans are available or where auto-calibration data are collected with each scan. We present experimental results using actual and simulated data to assess the performance of our approach in comparison with existing methods},
	booktitle = {4th {IEEE} {International} {Symposium} on {Biomedical} {Imaging}: {From} {Nano} to {Macro}, 2007. {ISBI} 2007},
	author = {Morrison, R.L. and Jacob, M. and Do, M.N.},
	month = apr,
	year = {2007},
	keywords = {biomedical MRI, channel estimation, image restoration, medical image processing, multichannel estimation, parallel MRI, receiver coil sensitivity, sum-of-squares technique},
	pages = {117 --120}
}

@inproceedings{vuissoz_high_2014,
	address = {Milano, Italy},
	title = {High {Resolution} {Cine} of the {Heart} at 3T with {Free} {Breathing} {Cine}-{GRICS}},
	booktitle = {{ISMRM}},
	author = {Vuissoz, Pierre-André and Odille, Freddy and Meyer, Christophe and Bonnemains, Laurent and Mandry, Damien and Felblinger, Jacques},
	year = {2014}
}

@article{steeden_assessing_2010,
	title = {Assessing vascular response to exercise using a combination of real‐time spiral phase contrast {MR} and noninvasive blood pressure measurements, {Assessing} vascular response to exercise using a combination of real‐time spiral phase contrast {MR} and noninvasive blood pressure measurements},
	volume = {31, 31},
	copyright = {Copyright © 2010 Wiley-Liss, Inc.},
	issn = {1522-2586, 1522-2586},
	url = {http://onlinelibrary.wiley.com.gate2.inist.fr/doi/10.1002/jmri.22105/abstract},
	doi = {10.1002/jmri.22105, 10.1002/jmri.22105},
	language = {en, en},
	number = {4, 4},
	urldate = {2012-04-16},
	journal = {Journal of Magnetic Resonance Imaging, Journal of Magnetic Resonance Imaging},
	author = {Steeden, Jennifer A and Atkinson, David and Taylor, Andrew M and Muthurangu, Vivek and Steeden, Jennifer A and Atkinson, David and Taylor, Andrew M and Muthurangu, Vivek},
	month = apr,
	year = {2010},
	keywords = {cardiovascular imaging, exercise, real‐time imaging},
	pages = {997, 997--1003, 1003}
}

@article{boudot_spatial_1990,
	title = {Spatial labeling by a radiofrequency field gradient. {DANTE}-{Z} profile, probed by one-dimensional nutation imaging},
	volume = {87},
	issn = {00222364},
	url = {http://apps.webofknowledge.com.gate2.inist.fr/InboundService.do?SID=3AH23e7iHMJ2O2Oaac3&product=WOS&UT=A1990CZ62300016&SrcApp=CR&DestFail=http%3A%2F%2Fwww.webofknowledge.com&Init=Yes&action=retrieve&Func=Frame&customersID=LinksAMR&SrcAuth=LinksAMR&IsProductCode=Yes&mode=FullRecord},
	doi = {10.1016/0022-2364(90)90016-3},
	number = {2},
	urldate = {2011-12-21},
	journal = {Journal of Magnetic Resonance (1969)},
	author = {Boudot, D},
	month = apr,
	year = {1990},
	pages = {385--394}
}

@article{hoskins_accuracy_1996,
	title = {Accuracy of maximum velocity estimates made using {Doppler} ultrasound systems},
	volume = {69},
	issn = {0007-1285, 1748-880X},
	url = {http://bjr.birjournals.org/content/69/818/172},
	doi = {10.1259/0007-1285-69-818-172},
	abstract = {This study was performed in order to provide quantitative data on the estimation of maximum velocity made using modern Doppler ultrasound systems. This is important since the degree of stenosis within arteries is commonly assessed from the maximum velocity. A string phantom was used as the source of Doppler signals. This enables direct comparison between the Doppler estimated maximum velocity and the true filament velocity. Six modern commercial Doppler systems were used. Measurements were made under standard conditions for each probe. In addition a number of factors were varied in turn (beam–filament angle, filament depth, filament velocity and Doppler aperture position). Under standard conditions the maximum velocity was overestimated in all cases (0–29\% error). For all measurements maximum velocity errors ranged from –4\% to 47\% There was a large intraprobe variation in maximum velocity estimation (mean variation of 25\%), and a large interprobe variation (mean variation of 18\%). These results indicate that, at present, errors in maximum velocity estimation may be directly translated into significant errors in the estimate of the degree of arterial stenosis made from velocity measurements. As a consequence, some patients may be incorrectly categorized. Consideration should be given to applying angle dependent correction factors to maximum velocity measurements, and to the use of conversion from Doppler frequency shift to velocity using the angle derived from the edge of the Doppler aperture.},
	language = {en},
	number = {818},
	urldate = {2012-11-06},
	journal = {British Journal of Radiology},
	author = {Hoskins, P. R.},
	month = feb,
	year = {1996},
	pages = {172--177}
}

@article{schaller_time--flight_2008,
	title = {Time-of-flight sensor for respiratory motion gating},
	volume = {35},
	issn = {0094-2405},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/18697533},
	abstract = {In this technical note we present a system that uses time-of-flight (ToF) technology to acquire a real-time multidimensional respiratory signal from a 3D surface reconstruction of the patient's chest and abdomen without the use of markers. Using ToF sensors it is feasible to acquire a 3D model in real time with a single sensor. An advantage of ToF sensors is that their high lateral resolution makes it possible to define multiple regions of interest to compute an anatomy-adaptive multidimensional respiratory signal. We evaluated the new approach by comparing a ToF based respiratory signal with the signal acquired by a commercially available external respiratory gating system and achieved an average correlation coefficient of 0.88.},
	number = {7},
	urldate = {2011-02-07},
	journal = {Medical Physics},
	author = {Schaller, Christian and Penne, Jochen and Hornegger, Joachim},
	month = jul,
	year = {2008},
	pmid = {18697533},
	keywords = {Algorithms, Artifacts, Calibration, Equipment Design, Humans, Image Processing, Computer-Assisted, Imaging, Three-Dimensional, Light, Models, Statistical, Models, Theoretical, Motion, Movement, Radiographic Image Enhancement, Reproducibility of Results, Respiration},
	pages = {3090--3093}
}

@article{wang_algorithms_1996,
	title = {Algorithms for extracting motion information from navigator echoes},
	volume = {36},
	issn = {0740-3194},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/8795030},
	abstract = {Algorithms to reliably detect motion in navigator echoes are crucial to many MRI motion suppression techniques. The accuracy of these algorithms is affected by noise and deformation of navigator echo profile caused by physiologic motion. This study compared the performance of algorithms based on correlation and least squares for extracting displacement information from motion-monitoring navigator echoes, using computer simulation and in vivo imaging. The least squares algorithm was determined to be of higher accuracy than the correlation algorithm against errors caused by noise and profile deformation.},
	number = {1},
	urldate = {2011-03-02},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Wang, Y and Grimm, R C and Felmlee, J P and Riederer, S J and Ehman, R L},
	month = jul,
	year = {1996},
	pmid = {8795030},
	keywords = {Algorithms, Artifacts, Brain, Computer Simulation, Diaphragm, Humans, Image Enhancement, Least-Squares Analysis, Magnetic Resonance Imaging, Motion, Nose, Respiration},
	pages = {117--123}
}

@article{chung_duration_2004,
	title = {Duration of diastole and its phases as a function of heart rate during supine bicycle exercise},
	volume = {287},
	issn = {0363-6135, 1522-1539},
	url = {http://ajpheart.physiology.org/content/287/5/H2003},
	doi = {10.1152/ajpheart.00404.2004},
	abstract = {The duration of diastole can be defined in terms of mechanical events. Mechanical diastolic duration (MDD) is comprised by the phases of early rapid filling (E wave), diastasis, and late atrial filling (A wave). The effect of heart rate (HR) on diastolic duration is predictable from kinematic modeling and known cellular physiology. To determine the dependence of MDD of each phase and the velocity time integral (VTI) on HR, simultaneous transmitral Doppler flow velocities and ECG were recorded during supine bicycle exercise in healthy volunteers. Durations, peak values, and VTI using triangular approximation for E- and A-wave shape were measured. MDD, defined as the interval from the start of the E wave to end of the A wave, was fit as an algebraic function of HR by MDD = BMDD + MLMDD·HR + MIMDD/HR, derivable from first principles, where BMDD is a constant, and MLMDD and MIMDD are the constant coefficients of the linear and inverse HR dependent terms. Excellent correlation was observed (r2 = 0.98). E- and A-wave durations were found to be very nearly independent of HR: 100\% increase in HR generated only an 18\% decrease in E-wave duration and 16\% decrease in A-wave duration. VTI was similarly very nearly independent of HR. Diastasis duration closely tracked MDD as a function of HR. We conclude that the elimination of diastasis and merging of E and A waves of nearly fixed durations primarily govern changes in MDD. These observations support the perspective that E- and A-wave durations are primarily governed by the rules of mechanical oscillation that are minimally HR dependent.},
	language = {en},
	number = {5},
	urldate = {2012-10-19},
	journal = {American Journal of Physiology - Heart and Circulatory Physiology},
	author = {Chung, Charles S. and Karamanoglu, Mustafa and Kovács, Sándor J.},
	month = nov,
	year = {2004},
	keywords = {A wave, E wave, Heart rate},
	pages = {H2003--H2008}
}

@article{strecker_flow-sensitive_2012,
	title = {Flow-sensitive 4D {MRI} of the thoracic aorta: {Comparison} of image quality, quantitative flow, and wall parameters at 1.5 {T} and 3 {T}},
	volume = {36},
	issn = {1522-2586},
	shorttitle = {Flow-sensitive 4D {MRI} of the thoracic aorta},
	doi = {10.1002/jmri.23735},
	abstract = {PURPOSE

To evaluate the effect of field strength on flow-sensitive 4D magnetic resonance imaging (MRI) of the thoracic aorta. A volunteer study at 1.5 T and 3 T was conducted to compare phase-contrast MR angiography (MRA) and 3D flow visualization quality as well as quantification of aortic hemodynamics.

MATERIALS AND METHODS

Ten healthy volunteers were examined by flow-sensitive 4D MRI at both 1.5 T and 3 T MRI with identical imaging parameters (TE/TR = 6/5.1 msec, spatial/temporal resolution ≈2 mm/40.8 msec). Analysis included assessment of image quality of derived aortic 3D phase contrast (PC) angiography and 3D flow visualization (semiquantitative grading on a 0-2 scale, two blinded observers) and quantification of blood flow velocities, net flow per cardiac cycle, wall shear stress (WSS), and velocity noise.

RESULTS

Quality of 3D blood flow visualization (average grading = 1.8 ± 0.4 at 3 T vs. 1.1 ± 0.7 at 1.5 T) and the depiction of aortic lumen geometry by 3D PC-MRA (1.7 ± 0.5 vs. 1.2 ± 0.6) were significantly (P {\textless} 0.01) improved at 3 T while velocity noise was significantly higher (P {\textless} 0.01) at 1.5 T. Velocity quantification resulted in minimally altered (0.05 m/s, 3 mL/cycle and 0.01 N/m(2) ) but not statistically different (P = 0.40, P = 0.39, and P = 0.82) systolic peak velocities, net flow, and WSS for 1.5 T compared to 3 T.

CONCLUSION

Flow-sensitive 4D MRI at 3 T provided improved image quality without additional artifacts related to higher fields. Imaging at 1.5 T MRI, which is more widely available, was also feasible and provided information on aortic 3D hemodynamics of moderate quality with identical performance regarding quantitative analysis. J. Magn. Reson. Imaging 2012;36:1097-1103. © 2012 Wiley Periodicals, Inc.},
	number = {5},
	journal = {Journal of magnetic resonance imaging: JMRI},
	author = {Strecker, Christoph and Harloff, Andreas and Wallis, Wolf and Markl, Michael},
	month = nov,
	year = {2012},
	pmid = {22745007},
	pages = {1097--1103}
}

@article{ortolano_advances_2010,
	title = {Advances in imaging of new targets for pharmacological intervention in stroke: real-time tracking of {T}-cells in the ischaemic brain},
	volume = {159},
	issn = {1476-5381},
	shorttitle = {Advances in imaging of new targets for pharmacological intervention in stroke},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/20015295},
	doi = {10.1111/j.1476-5381.2009.00527.x},
	abstract = {{\textless}AbstractText Label="BACKGROUND AND PURPOSE" NlmCategory="OBJECTIVE"{\textgreater}T-cells may play a role in the evolution of ischaemic damage and repair, but the ability to image these cells in the living brain after a stroke has been limited. We aim to extend the technique of real-time in situ brain imaging of T-cells, previously shown in models of immunological diseases, to models of experimental stroke.{\textless}/AbstractText{\textgreater}
{\textless}AbstractText Label="EXPERIMENTAL APPROACH" NlmCategory="METHODS"{\textgreater}Male C57BL6 mice (6-8 weeks) (n= 3) received a total of 2-5 x 10(6) carboxyfluorescein diacetate succinimidyl ester (CFSE)-labelled lymphocytes from donor C57BL6 mice via i.v. injection by adoptive transfer. Twenty-four hours later, recipient mice underwent permanent left distal middle cerebral artery occlusion (MCAO) by electrocoagulation or by sham surgery under isoflurane anaesthesia. Female hCD2-green fluorescent protein (GFP) transgenic mice that exhibit GFP-labelled T-cells underwent MCAO. At 24 or 48 h post-MCAO, a sagittal brain slice (1500 microm thick) containing cortical branches of the occluded middle cerebral artery (MCA) was dissected and used for multiphoton laser scanning microscopy (MPLSM).{\textless}/AbstractText{\textgreater}
{\textless}AbstractText Label="KEY RESULTS" NlmCategory="RESULTS"{\textgreater}Our results provide direct observations for the first time of dynamic T-cell behaviour in living brain tissue in real time and herein proved the feasibility of MPLSM for ex vivo live imaging of immune response after experimental stroke.{\textless}/AbstractText{\textgreater}
{\textless}AbstractText Label="CONCLUSIONS AND IMPLICATIONS" NlmCategory="CONCLUSIONS"{\textgreater}It is hoped that these advances in the imaging of immune cells will provide information that can be harnessed to a therapeutic advantage.{\textless}/AbstractText{\textgreater}},
	number = {4},
	urldate = {2011-01-03},
	journal = {British Journal of Pharmacology},
	author = {Ortolano, F and Maffia, P and Dever, G and Rodolico, G and Millington, O R and De Simoni, M G and Brewer, J M and Bushell, T J and Garside, P and Carswell, H V},
	month = feb,
	year = {2010},
	pmid = {20015295},
	keywords = {Adoptive Transfer, Animals, Brain, Disease Models, Animal, Feasibility Studies, Female, Fluoresceins, Fluorescent Dyes, Green Fluorescent Proteins, Infarction, Middle Cerebral Artery, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Microscopy, Fluorescence, Multiphoton, Molecular Imaging, Molecular Probe Techniques, Succinimides, T-Lymphocytes, Time Factors},
	pages = {808--811}
}

@article{occhetta_electrical_2010,
	title = {Do electrical parameters of the cardiac cycle reflect the corresponding mechanical intervals as the heart rate changes?},
	volume = {12},
	issn = {1099-5129, 1532-2092},
	url = {http://europace.oxfordjournals.org/content/12/6/830},
	doi = {10.1093/europace/euq068},
	abstract = {Aims The evoked QT interval can be detected beat by beat through an implanted pacing system. The correlation between the right ventricular paced QT interval and the left ventricular systolic interval is not known. The aim of our study was to collect data on the correlation between QT and systolic and diastolic indexes at different heart rates in patients with dual-chamber rate-responsive pacemakers.
Method and results The study involved 13 patients [67 ± 9 years; ejection fraction (EF) 52 ± 10\%] with standard indication for dual-chamber pacing. Patients were evaluated at rest in the supine position. The AV delay was set at 130 ms, and the pacing rate was increased from 90 to 130 bpm (10 bpm steps for 3 min). At the end of each 3 min step, QT intervals were automatically evaluated in real time by means of pacemaker telemetry. We also evaluated heart performance by means of echo-2D (end-diastolic/end-systolic volumes, EF) and echo-Doppler measurements [left ventricular ejection time (LVET) and diastolic filling time (LVDFT), aortic velocity time integral, and systolic volume] and systemic arterial pressure. The QT interval progressively decreased from 330 ± 20 to 280 ± 10 ms as the pacing rate was increased from 90 to 130 bpm. The correlation between the QT interval and LVET as a function of the pacing rate was R2 = 0.966, indicating a good and relatively parallel trend in these two parameters. The correlation between RR-QT (reflecting electrical diastole) and LVDFT (reflecting mechanical diastole) was R2 = 0.975. The index LVET/QT (ratio between mechanical and electrical systole) was constant in the range 90–120 bpm, but significantly decreased at 130 bpm: the mechanical LVET shortens more than the electrical QT does at the highest heart rates.
Conclusion In paced patients at rest and during artificially increased heart rates, QT interval dynamics is closely correlated with changes in ejection time, thus constituting an electrical parameter of systolic time. A similar correlation exists between RR-QT, as a diastolic electrical interval, and the DFT.},
	language = {en},
	number = {6},
	urldate = {2012-10-19},
	journal = {Europace},
	author = {Occhetta, Eraldo and Corbucci, Giorgio and Bortnik, Miriam and Pedrigi, Cristina and Said, Salah A. M. and Droste, Herman T. and Hofmann, Robert and Marino, Paolo},
	month = jun,
	year = {2010},
	keywords = {Cardiac resynchronization therapy, Ejection time, QT interval, Rate-responsive pacing},
	pages = {830--834}
}

@article{jung_navigator_2006-1,
	title = {Navigator gated high temporal resolution tissue phase mapping of myocardial motion},
	volume = {55},
	issn = {0740-3194},
	doi = {10.1002/mrm.20808},
	abstract = {Data acquisition for phase contrast velocity mapping of myocardial motion is typically based on multiple breath-held 2D measurements with limited acquisition duration and consequently relatively poor temporal resolution. In order to overcome the limitations of breath-hold acquisitions, an improved navigator-guided technique was implemented based on 2 navigator signals within each cardiac cycle in combination with paired acceptance and rejection criteria of successive navigator signals. Respiratory gated phase contrast measurements with 3-directional velocity encoding were performed in 12 healthy volunteers in basal, midventricular, and apical locations of the left ventricle during free breathing with a temporal resolution of 13.8 ms. Results were compared to standard breath-hold measurements with a temporal resolution of 69 ms. Data from the high temporal resolution study revealed details in left ventricular motion patterns that were previously not seen in phase contrast measurements and are only known from echocardiography. The proposed navigator gated technique for high temporal resolution velocity mapping is, therefore, highly promising for the detection of local and global motion abnormalities in patients with disturbed left ventricular performance, such as diastolic dysfunction.},
	language = {eng},
	number = {4},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Jung, Bernd and Zaitsev, Maxim and Hennig, Jürgen and Markl, Michael},
	month = apr,
	year = {2006},
	pmid = {16450375},
	keywords = {Adult, Aged, Artifacts, Blood Flow Velocity, Coronary Circulation, Humans, Image Enhancement, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Middle Aged, Myocardial Contraction},
	pages = {937--942}
}

@article{kagadis_cloud_2013,
	title = {Cloud computing in medical imaging},
	volume = {40},
	copyright = {© 2013 American Association of Physicists in Medicine},
	url = {http://link.aip.org/link/?MPH/40/070901/1},
	doi = {10.1118/1.4811272},
	abstract = {Over the past century technology has played a decisive role in defining, driving, and reinventing procedures, devices, and pharmaceuticals in healthcare. Cloud computing has been introduced only recently but is already one of the major topics of discussion in research and clinical settings. The provision of extensive, easily accessible, and reconfigurable resources such as virtual systems, platforms, and applications with low service cost has caught the attention of many researchers and clinicians. Healthcare researchers are moving their efforts to the cloud, because they need adequate resources to process, store, exchange, and use large quantities of medical data. This Vision 20/20 paper addresses major questions related to the applicability of advanced cloud computing in medical imaging. The paper also considers security and ethical issues that accompany cloud computing.},
	number = {7},
	urldate = {2013-08-28},
	journal = {Medical Physics},
	author = {Kagadis, George C. and Kloukinas, Christos and Moore, Kevin and Philbin, Jim and Papadimitroulas, Panagiotis and Alexakos, Christos and Nagy, Paul G. and Visvikis, Dimitris and Hendee, William R.},
	year = {2013},
	keywords = {Biomedical imaging, cloud computing, health care, medical computing},
	pages = {070901}
}

@article{lustig_sparse_2007,
	title = {Sparse {MRI}: {The} application of compressed sensing for rapid {MR} imaging},
	volume = {58},
	copyright = {Copyright © 2007 Wiley-Liss, Inc.},
	issn = {1522-2594},
	shorttitle = {Sparse {MRI}},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.21391/abstract},
	doi = {10.1002/mrm.21391},
	abstract = {The sparsity which is implicit in MR images is exploited to significantly undersample k-space. Some MR images such as angiograms are already sparse in the pixel representation; other, more complicated images have a sparse representation in some transform domain–for example, in terms of spatial finite-differences or their wavelet coefficients. According to the recently developed mathematical theory of compressed-sensing, images with a sparse representation can be recovered from randomly undersampled k-space data, provided an appropriate nonlinear recovery scheme is used. Intuitively, artifacts due to random undersampling add as noise-like interference. In the sparse transform domain the significant coefficients stand out above the interference. A nonlinear thresholding scheme can recover the sparse coefficients, effectively recovering the image itself. In this article, practical incoherent undersampling schemes are developed and analyzed by means of their aliasing interference. Incoherence is introduced by pseudo-random variable-density undersampling of phase-encodes. The reconstruction is performed by minimizing the ℓ1 norm of a transformed image, subject to data fidelity constraints. Examples demonstrate improved spatial resolution and accelerated acquisition for multislice fast spin-echo brain imaging and 3D contrast enhanced angiography. Magn Reson Med, 2007. © 2007 Wiley-Liss, Inc.},
	language = {en},
	number = {6},
	urldate = {2012-11-08},
	journal = {Magnetic Resonance in Medicine},
	author = {Lustig, Michael and Donoho, David and Pauly, John M.},
	year = {2007},
	keywords = {compressed sensing, compressive sampling, nonlinear reconstruction, random sampling, rapid MRI, sparse reconstruction, sparsity},
	pages = {1182--1195}
}

@article{constantine_role_2004,
	title = {Role of {MRI} in clinical cardiology},
	volume = {363},
	issn = {1474-547X},
	doi = {10.1016/S0140-6736(04)16509-4},
	abstract = {Rapid progress has been made in cardiac MRI (CMRI) over the past decade, which has firmly established it as a reliable and clinically important technique for assessment of cardiac structure, function, perfusion, and myocardial viability. Its versatility and accuracy is unmatched by any other individual imaging modality. CMRI is non-invasive and has high spatial resolution and avoids use of potentially nephrotoxic contrast agent or radiation. It has been extensively studied against other established non-invasive imaging modalities and has been shown to be superior in many scenarios, particularly with respect to assessment of cardiac and great vessel morphology and left ventricular function. Furthermore, its clinical use continues to expand with increasing experience and proliferation of CMRI centres. As worldwide prevalence of cardiovascular disease continues to rise, CMRI provides opportunity for improved and cost-effective non-invasive assessment. Continued progress in CMRI technology promises to further widen its clinical application in coronary imaging, myocardial perfusion, comprehensive assessment of valves, and plaque characterisation.},
	number = {9427},
	journal = {Lancet},
	author = {Constantine, Godwin and Shan, Kesavan and Flamm, Scott D and Sivananthan, Mohan U},
	month = jun,
	year = {2004},
	pmid = {15220041},
	keywords = {Aortic Diseases, Cardiomyopathies, Coronary Circulation, Heart Defects, Congenital, Heart Diseases, Heart Neoplasms, Heart Valve Diseases, Humans, Magnetic Resonance Imaging, Myocardial Contraction, Myocardial Ischemia, hemodynamics},
	pages = {2162--2171}
}

@article{xie_high_nodate,
	title = {High resolution dynamic cardiac {MRI} using partial separability of spatiotemporal signals with a novel sampling scheme},
	issn = {0730-725X},
	url = {http://www.sciencedirect.com/science/article/pii/S0730725X12004134},
	doi = {10.1016/j.mri.2012.10.014},
	abstract = {Abstract
The partial separability (PS) of spatiotemporal signals has been exploited to accelerate dynamic cardiac MRI by sampling two datasets (training and imaging datasets) without breath-holding or ECG triggering. According to the theory of partially separable functions, the wider the range of spatial frequency components covered by the training dataset, the more accurate the temporal constraint imposed by the PS model. Therefore, it is necessary to develop a new sampling scheme for the PS model in order to cover a wider range of spatial frequency components. In this paper, we propose the use of radial sampling trajectories for collecting the training dataset and Cartesian sampling trajectories for collecting the imaging dataset. In vivo high resolution cardiac MRI experiments demonstrate that the proposed data sampling scheme can significantly improve the image quality. The image quality using the PS model with the proposed sampling scheme is comparable to that of a commercial method using retrospective cardiac gating and breath-holding. The success of this study demonstrates great potential for high-quality, high resolution dynamic cardiac MRI without ECG gating or breath-holding through use of the PS model and the novel data sampling scheme.},
	number = {0},
	urldate = {2013-01-17},
	journal = {Magnetic Resonance Imaging},
	author = {Xie, Guoxi and Feng, Xiang and Christodoulou, Anthony G. and Weng, Dehe and Liu, Xin and Qiu, Bensheng},
	keywords = {Dynamic cardiac MRI, Partially separable functions, Radial sampling trajectory}
}

@article{xu_partial_2001,
	title = {Partial {Fourier} imaging in multi-dimensions: {A} means to save a full factor of two in time},
	volume = {14},
	copyright = {Copyright © 2001 Wiley-Liss, Inc.},
	issn = {1522-2586},
	shorttitle = {Partial {Fourier} imaging in multi-dimensions},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/jmri.1228/abstract},
	doi = {10.1002/jmri.1228},
	abstract = {We present an improvement to the traditional one-dimensional partial Fourier method by extending the method to multi-dimensions. The modified method allowed a full factor of two savings in time with much better coverage of the central k-space information and, because of this, smaller reconstruction artifacts. The residual magnitude error was found to correlate strongly with the residual phase error. Numerical simulation also indicated that with a priori perfect phase information, the original magnitude image could be perfectly reconstructed with half of the k-space data points in the multi-dimensional case. Simulated, phantom, and human data sets were tested with edge differences ranging from 10\% (consistent with variable Gibbs ringing) to 25\% (consistent with a blurred version of the object). The method was found to be a valuable adjunct to human imaging for short TR, T1-weighted three-dimensional gradient-echo imaging and magnetic resonance (MR) angiographic methods, especially when short echo times were used. J. Magn. Reson. Imaging 2001;14:628–635. © 2001 Wiley-Liss, Inc.},
	language = {en},
	number = {5},
	urldate = {2012-08-21},
	journal = {Journal of Magnetic Resonance Imaging},
	author = {Xu, Yingbiao and Haacke, E. Mark},
	year = {2001},
	keywords = {image reconstruction, minimum data acquisition, partial Fourier imaging, phase constraints, rapid imaging},
	pages = {628--635}
}

@article{jung_undersampling_2011,
	title = {On the undersampling strategies to accelerate time-resolved 3D imaging using k-t-{GRAPPA}},
	volume = {66},
	copyright = {Copyright © 2011 Wiley-Liss, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.22875/abstract},
	doi = {10.1002/mrm.22875},
	abstract = {The purpose of this study was to explore how to optimally undersample and reconstruct time-resolved 3D data using a k-t-space-based GRAPPA technique. The performance of different reconstruction strategies was evaluated using data sets with different ratios of phase (Ny) and partition (Nz) encoding lines (Ny × Nz = 64–128 × 40–64) acquired in a moving phantom. Image reconstruction was performed for different kernel configurations and different reduction factors (R = 5, 6, 8, and 10) and was evaluated using regional error quantification and SNR analysis. To analyze the temporal fidelity of the different kernel configurations in vivo, time-resolved 3D phase contrast data were acquired in the thoracic aorta of two healthy volunteers. Results demonstrated that kernel configurations with a small kernel extension yielded superior results especially for more asymmetric data matrices as typically used in clinical applications. The application of k-t-GRAPPA to in vivo data demonstrated the feasibility of undersampling of time-resolved 3D phase contrast data set with a nominal reduction factors of up to Rnet = 8, while maintaining the temporal fidelity of the measured velocity field. Extended GRAPPA-based parallel imaging with optimized multidimensional reconstruction kernels has the potential to substantially accelerate data acquisitions in time-resolved 3D MRI. Magn Reson Med, 2011. © 2011 Wiley-Liss, Inc.},
	language = {en},
	number = {4},
	urldate = {2013-07-24},
	journal = {Magnetic Resonance in Medicine},
	author = {Jung, Bernd and Stalder, Aurélien F. and Bauer, Simon and Markl, Michael},
	year = {2011},
	keywords = {GRAPPA, dynamic imaging, parallel MRI, time-resolved 3D imaging},
	pages = {966--975}
}

@article{jenkinson_fast_2003-2,
	title = {Fast, automated, {N}-dimensional phase-unwrapping algorithm},
	volume = {49},
	copyright = {Copyright © 2003 Wiley-Liss, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.10354/abstract},
	doi = {10.1002/mrm.10354},
	abstract = {This work investigates the general problem of phase unwrapping for arbitrary N-dimensional phase maps. A cost function-based approach is outlined that leads to an integer programming problem. To solve this problem, a best-pair-first region merging approach is adopted as the optimization method. The algorithm was implemented and tested with 3D MRI medical data for venogram studies, as well as for fMRI applications in EPI unwarping and rapid, automated shimming. Magn Reson Med 49:193–197, 2003. © 2003 Wiley-Liss, Inc.},
	language = {en},
	number = {1},
	urldate = {2012-07-23},
	journal = {Magnetic Resonance in Medicine},
	author = {Jenkinson, Mark},
	year = {2003},
	keywords = {automated shimming, echo planar imaging (EPI), field mapping, phase unwrapping, venogram},
	pages = {193--197}
}

@article{white_promo:_2010,
	title = {{PROMO}: {Real}-time prospective motion correction in {MRI} using image-based tracking},
	volume = {63},
	issn = {07403194},
	shorttitle = {{PROMO}},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.22176/full},
	doi = {10.1002/mrm.22176},
	number = {1},
	urldate = {2011-02-07},
	journal = {Magnetic Resonance in Medicine},
	author = {White, Nathan and Roddey, Cooper and Shankaranarayanan, Ajit and Han, Eric and Rettmann, Dan and Santos, Juan and Kuperman, Josh and Dale, Anders},
	month = jan,
	year = {2010},
	pages = {91--105}
}

@article{otazo_combination_2010,
	title = {Combination of compressed sensing and parallel imaging for highly accelerated first-pass cardiac perfusion {MRI}},
	volume = {64},
	copyright = {Copyright © 2010 Wiley-Liss, Inc.},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.22463/abstract},
	doi = {10.1002/mrm.22463},
	abstract = {First-pass cardiac perfusion MRI is a natural candidate for compressed sensing acceleration since its representation in the combined temporal Fourier and spatial domain is sparse and the required incoherence can be effectively accomplished by k-t random undersampling. However, the required number of samples in practice (three to five times the number of sparse coefficients) limits the acceleration for compressed sensing alone. Parallel imaging may also be used to accelerate cardiac perfusion MRI, with acceleration factors ultimately limited by noise amplification. In this work, compressed sensing and parallel imaging are combined by merging the k-t SPARSE technique with sensitivity encoding (SENSE) reconstruction to substantially increase the acceleration rate for perfusion imaging. We also present a new theoretical framework for understanding the combination of k-t SPARSE with SENSE based on distributed compressed sensing theory. This framework, which identifies parallel imaging as a distributed multisensor implementation of compressed sensing, enables an estimate of feasible acceleration for the combined approach. We demonstrate feasibility of 8-fold acceleration in vivo with whole-heart coverage and high spatial and temporal resolution using standard coil arrays. The method is relatively insensitive to respiratory motion artifacts and presents similar temporal fidelity and image quality when compared to Generalized autocalibrating partially parallel acquisitions (GRAPPA) with 2-fold acceleration. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.},
	language = {en},
	number = {3},
	urldate = {2012-11-08},
	journal = {Magnetic Resonance in Medicine},
	author = {Otazo, Ricardo and Kim, Daniel and Axel, Leon and Sodickson, Daniel K.},
	year = {2010},
	keywords = {cardiac perfusion, compressed sensing, dynamic imaging, parallel imaging: joint sparsity},
	pages = {767--776}
}

@inproceedings{noauthor_banding_nodate,
	title = {Banding {Artifact} {Reduction} in 2D {CINE} {Balanced} {SSFP} at 3.0 {T} {Using} {Phase}-{Cycling} and k-t {BLAST}}
}

@article{brickner_dissociation_1990,
	title = {Dissociation of end systole from end ejection in patients with long-term mitral regurgitation},
	volume = {81},
	issn = {0009-7322},
	abstract = {To determine whether left ventricular (LV) end systole and end ejection uncouple in patients with long-term mitral regurgitation, 59 patients (22 control patients with atypical chest pain, 21 patients with aortic regurgitation, and 16 patients with mitral regurgitation) were studied with micromanometer LV catheters and radionuclide angiograms. End systole was defined as the time of occurrence (Tmax) of the maximum time-varying elastance (Emax), and end ejection was defined as the time of occurrence of minimum ventricular volume (minV) and zero systolic flow as approximated by the aortic dicrotic notch (Aodi). The temporal relation between end systole and end ejection in the control patients was Tmax (331 +/- 42 [SD] msec), minV (336 +/- 36 msec), and then, zero systolic flow (355 +/- 23 msec). This temporal relation was maintained in the patients with aortic regurgitation. In contrast, in the patients with mitral regurgitation, the temporal relation was Tmax (266 +/- 49 msec), zero systolic flow (310 +/- 37 msec, p less than 0.01 vs. Tmax), and then, minV (355 +/- 37 msec, p less than 0.001 vs. Tmax and p less than 0.01 vs. Aodi). Additionally, the average Tmax occurred earlier in the patients with mitral regurgitation than in the control patients and patients with aortic regurgitation (p less than 0.01, for both), whereas the average time to minimum ventricular volume was similar in all three patient groups. Moreover, the average time to zero systolic flow also occurred earlier in the patients with mitral regurgitation than in the control patients (p less than 0.01) and patients with aortic regurgitation (p less than 0.05). Because of the dissociation of end systole from minimum ventricular volume in the patients with mitral regurgitation, the end-ejection pressure-volume relations calculated at minimum ventricular volume did not correlate (r = -0.09), whereas those calculated at zero systolic flow did correlate (r = 0.88) with the Emax slope values. We conclude that end ejection, defined as minimum ventricular volume, dissociates from end systole in patients with mitral regurgitation because of the shortened time to LV end systole in association with preservation of the time to LV end ejection due to the low impedance to ejection presented by the left atrium. Therefore, pressure-volume relations calculated at minimum ventricular volume might not be useful for assessing LV chamber performance in some patients with mitral regurgitation.},
	language = {eng},
	number = {4},
	journal = {Circulation},
	author = {Brickner, M E and Starling, M R},
	month = apr,
	year = {1990},
	pmid = {2317909},
	keywords = {Chronic Disease, Elasticity, Heart, Heart Ventricles, Humans, Mitral Valve Insufficiency, Myocardial Contraction, Stroke Volume, Systole, Time Factors, hemodynamics},
	pages = {1277--1286}
}

@article{espe_novel_2013,
	title = {Novel insight into the detailed myocardial motion and deformation of the rodent heart using high-resolution phase contrast cardiovascular magnetic resonance},
	volume = {15},
	copyright = {2013 Espe et al.; licensee BioMed Central Ltd.},
	issn = {1532-429X},
	url = {http://www.jcmr-online.com/content/15/1/82/abstract},
	doi = {10.1186/1532-429X-15-82},
	abstract = {Phase contrast velocimetry cardiovascular magnetic resonance (PC-CMR) is a powerful and versatile tool allowing assessment of in vivo motion of the myocardium. However, PC-CMR is sensitive to motion related artifacts causing errors that are geometrically systematic, rendering regional analysis of myocardial function challenging. The objective of this study was to establish an optimized PC-CMR method able to provide novel insight in the complex regional motion and strain of the rodent myocardium, and provide a proof-of-concept in normal and diseased rat hearts with higher temporal and spatial resolution than previously reported.
PMID: 24034168},
	language = {en},
	number = {1},
	urldate = {2014-01-08},
	journal = {Journal of Cardiovascular Magnetic Resonance},
	author = {Espe, Emil KS and Aronsen, Jan M. and Skårdal, Kristine and Schneider, Jürgen E. and Zhang, Lili and Sjaastad, Ivar},
	month = sep,
	year = {2013},
	pmid = {24034168},
	keywords = {3D phase contrast, CMR, Myocardial strain, Strain analysis, motion artifacts, myocardial motion, tissue phase mapping},
	pages = {82},
	file = {Full Text PDF:/Users/cmey/Zotero/storage/8BHT74FC/Espe et al. - 2013 - Novel insight into the detailed myocardial motion .pdf:application/pdf;Snapshot:/Users/cmey/Zotero/storage/HBME8FDN/abstract.html:text/html}
}

@article{kim_accelerated_2012-2,
	title = {Accelerated phase-contrast cine {MRI} using k-t {SPARSE}-{SENSE}},
	volume = {67},
	issn = {1522-2594},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/22083998},
	doi = {10.1002/mrm.23088},
	abstract = {Phase-contrast (PC) cine MRI is a promising method for assessment of pathologic hemodynamics, including cardiovascular and hepatoportal vascular dynamics, but its low data acquisition efficiency limits the achievable spatial and temporal resolutions within clinically acceptable breath-hold durations. We propose to accelerate PC cine MRI using an approach which combines compressed sensing and parallel imaging (k-t SPARSE-SENSE). We validated the proposed 6-fold accelerated PC cine MRI against 3-fold accelerated PC cine MRI with parallel imaging (generalized autocalibrating partially parallel acquisitions). With the programmable flow pump, we simulated a time varying waveform emulating hepatic blood flow. Normalized root mean square error between two sets of velocity measurements was 2.59\%. In multiple blood vessels of 12 control subjects, two sets of mean velocity measurements were in good agreement (mean difference = -0.29 cm/s; lower and upper 95\% limits of agreement = -5.26 and 4.67 cm/s, respectively). The mean phase noise, defined as the standard deviation of the phase in a homogeneous stationary region, was significantly lower for k-t SPARSE-SENSE than for generalized autocalibrating partially parallel acquisitions (0.05 ± 0.01 vs. 0.19 ± 0.06 radians, respectively; P {\textless} 0.01). The proposed 6-fold accelerated PC cine MRI pulse sequence with k-t SPARSE-SENSE is a promising investigational method for rapid velocity measurement with relatively high spatial (1.7 mm × 1.7 mm) and temporal (∼35 ms) resolutions.},
	number = {4},
	urldate = {2012-06-04},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Kim, Daniel and Dyvorne, Hadrien A and Otazo, Ricardo and Feng, Li and Sodickson, Daniel K and Lee, Vivian S},
	month = apr,
	year = {2012},
	pmid = {22083998},
	keywords = {Adult, Algorithms, Blood Flow Velocity, Cardiac-Gated Imaging Techniques, Computer Simulation, Female, Humans, Image Enhancement, Image Processing, Computer-Assisted, Liver, Magnetic Resonance Imaging, Cine, Male, Phantoms, Imaging},
	pages = {1054--1064}
}

@article{dietrich_measurement_2007,
	title = {Measurement of signal-to-noise ratios in {MR} images: {Influence} of multichannel coils, parallel imaging, and reconstruction filters},
	volume = {26},
	copyright = {Copyright © 2007 Wiley-Liss, Inc.},
	issn = {1522-2586},
	shorttitle = {Measurement of signal-to-noise ratios in {MR} images},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/jmri.20969/abstract},
	doi = {10.1002/jmri.20969},
	abstract = {PurposeTo evaluate the validity of different approaches to determine the signal-to-noise ratio (SNR) in MRI experiments with multi-element surface coils, parallel imaging, and different reconstruction filters.Materials and MethodsFour different approaches of SNR calculation were compared in phantom measurements and in vivo based on: 1) the pixel-by-pixel standard deviation (SD) in multiple repeated acquisitions; 2) the signal statistics in a difference image; and 3) and 4) the statistics in two separate regions of a single image employing either the mean value or the SD of background noise. Different receiver coil systems (with one and eight channels), acquisitions with and without parallel imaging, and five different reconstruction filters were compared.ResultsAveraged over all phantom measurements, the deviations from the reference value provided by the multiple-acquisitions method are 2.7\% (SD 1.6\%) for the difference method, 37.7\% (25.9\%) for the evaluation of the mean value of background noise, and 34.0\% (38.1\%) for the evaluation of the SD of background noise.ConclusionThe conventionally determined SNR based on separate signal and noise regions in a single image will in general not agree with the true SNR measured in images after the application of certain reconstruction filters, multichannel reconstruction, or parallel imaging. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc.},
	language = {en},
	number = {2},
	urldate = {2013-04-16},
	journal = {Journal of Magnetic Resonance Imaging},
	author = {Dietrich, Olaf and Raya, José G. and Reeder, Scott B. and Reiser, Maximilian F. and Schoenberg, Stefan O.},
	year = {2007},
	keywords = {MR imaging, image analysis, parallel imaging, postprocessing filters, signal-to-noise ratio},
	pages = {375--385}
}

@article{sampath_imaging_2011,
	title = {Imaging left ventricular tissue mechanics and hemodynamics during supine bicycle exercise using a combined tagging and phase-contrast {MRI} pulse sequence},
	volume = {65},
	issn = {1522-2594},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/21053325},
	doi = {10.1002/mrm.22668},
	abstract = {Imaging the left ventricular mechanical and hemodynamic response to the stress of exercise may offer early prognosis in select patients with cardiac disease. Here, we demonstrate the feasibility of obtaining simultaneous measurements of longitudinal strain and transvalvular blood velocity during supine bicycle exercise stress in a wide bore magnetic resonance scanner. Combining information from the two datasets, we observe that although the time to peak strain (33.28 ± 1.86 versus 25.7 ± 2.12 as \% of R-R interval) and time to peak mitral inflow velocity (44.37 ± 5.21 versus 35.5 ± 4.19 as \% of R-R interval) from R-wave of the QRS complex occurred earlier during stress, the time from peak strain to peak mitral inflow velocity was not statistically different (16.5 ± 3.23 versus 13.4 ± 3.06). Further, the percentage of longitudinal relaxation at peak mitral inflow velocity was higher during stress (63.5 ± 7.72 versus 84.32 ± 6.24). These results suggest that although diastole is shortened, early diastolic filling efficiency is augmented during exercise stress in normal volunteers in an effort to maintain stroke volume. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc.},
	number = {1},
	urldate = {2011-01-03},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Sampath, Smita and Derbyshire, John Andrew and Ledesma-Carbayo, Maria J and McVeigh, Elliot R},
	month = jan,
	year = {2011},
	pmid = {21053325},
	keywords = {Algorithms, Blood Flow Velocity, Blood Pressure, Elastic Modulus, Elasticity Imaging Techniques, Exercise Test, Female, Humans, Image Enhancement, Image Interpretation, Computer-Assisted, Magnetic Resonance Imaging, Male, Physical Exertion, Pilot Projects, Reproducibility of Results, Sensitivity and Specificity, Signal Processing, Computer-Assisted, Supine Position, Ventricular Function, Left},
	pages = {51--59}
}

@article{roemer_nmr_1990,
	title = {The {NMR} phased array},
	volume = {16},
	copyright = {Copyright © 1990 Wiley-Liss, Inc., A Wiley Company},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.1910160203/abstract},
	doi = {10.1002/mrm.1910160203},
	abstract = {We describe methods for simultaneously acquiring and subsequently combining data from a multitude of closely positioned NMR receiving coils. The approach is conceptually similar to phased array radar and ultrasound and hence we call our techniques the “NMR phased array.” The NMR phased array offers the signal-to-noise ratio (SNR) and resolution of a small surface coil over fields-of-view (FOV) normally associated with body imaging with no increase in imaging time. The NMR phased array can be applied to both imaging and spectroscopy for all pulse sequences. The problematic interactions among nearby surface coils is eliminated (a) by overlapping adjacent coils to give zero mutual inductance, hence zero interaction, and (b) by attaching low input impedance preamplifiers to all coils, thus eliminating interference among next nearest and more distant neighbors. We derive an algorithm for combining the data from the phased array elements to yield an image with optimum SNR. Other techniques which are easier to implement at the cost of lower SNR are explored. Phased array imaging is demonstrated with high resolution (512 × 512, 48-cm FOV, and 32-cm FOV) spin-echo images of the thoracic and lumbar spine. Data were acquired from four-element linear spine arrays, the first made of 12-cm square coils and the second made of 8-cm square coils. When compared with images from a single 15 × 30-cm rectangular coil and identical imaging parameters, the phased array yields a 2X and 3X higher SNR at the depth of the spine ( ∼ 7 cm). © 1990 Academic Press, Inc.},
	language = {en},
	number = {2},
	urldate = {2012-09-05},
	journal = {Magnetic Resonance in Medicine},
	author = {Roemer, P. B. and Edelstein, W. A. and Hayes, C. E. and Souza, S. P. and Mueller, O. M.},
	year = {1990},
	pages = {192--225}
}

@article{dewan_image-based_2008,
	title = {Image-based coronary tracking and beat-to-beat motion compensation: {Feasibility} for improving coronary {MR} angiography},
	volume = {60},
	copyright = {Copyright © 2008 Wiley-Liss, Inc.},
	issn = {1522-2594},
	shorttitle = {Image-based coronary tracking and beat-to-beat motion compensation},
	url = {http://onlinelibrary.wiley.com/doi/10.1002/mrm.21663/abstract},
	doi = {10.1002/mrm.21663},
	abstract = {A method to reduce the effect of motion variability in MRI of the coronary arteries is proposed. It involves acquiring real-time low-resolution images in specific orthogonal orientations, extracting coronary motion from these images, and then using this motion information to guide high-resolution MR image acquisition on a beat-to-beat basis. The present study establishes the feasibility and efficacy of the proposed approach using human motion data in an offline implementation, prior to future online implementation on an MRI scanner. To track the coronary arteries in low-resolution real-time MR images in an accurate manner, a tracking approach is presented and validated. The tracking algorithm was run on real-time images acquired at 15–20 frames per second in four-chamber, short-axis, and coronal views in five volunteers. The systolic and diastolic periods in the cardiac cycles, computed from the extracted motion information, had significant variability during the short time periods typical of cardiac MRI. It is also demonstrated through simulation analysis using human tracked coronary motion data that accounting for this cardiac variability by adaptively changing the trigger delay for acquisition on a beat-to-beat basis improves overall motion compensation and hence MR image quality evaluated in terms of SNR and CNR values. Magn Reson Med 60:604–615, 2008. © 2008 Wiley-Liss, Inc.},
	language = {en},
	number = {3},
	urldate = {2013-10-31},
	journal = {Magnetic Resonance in Medicine},
	author = {Dewan, Maneesh and Hager, Gregory D. and Lorenz, Christine H.},
	year = {2008},
	keywords = {Motion compensation, adaptive trigger delay, coronary magnetic resonance angiography, heart rate variability, image-based motion tracking, template tracking},
	pages = {604--615},
	file = {Snapshot:/Users/cmey/Zotero/storage/2G326TR9/abstract.html:text/html}
}

@article{feinberg_inner_1985,
	title = {Inner volume {MR} imaging: technical concepts and their application},
	volume = {156},
	issn = {0033-8419},
	shorttitle = {Inner volume {MR} imaging},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/4023236},
	abstract = {Although cross-sectional magnetic resonance examination of the head and body is useful for screening large regions of tissue, subsectional regions of the head and body often need to be examined. Orthogonally directed, selectively irradiated planes with different flip angles produce a spatially limited signal region from which two- or three-dimensional volume images can be reconstructed. Images with limited fields-of-view can be acquired in reduced imaging time. We present a general description of this technique. These subsectional or "inner volume" images eliminate respiratory motion artifacts by excluding moving tissues from the imaged volume. A result of this technique is a high signal from rapid pulsatile blood flow, produced without cardiac gating the pulse sequence.},
	number = {3},
	urldate = {2012-08-09},
	journal = {Radiology},
	author = {Feinberg, D A and Hoenninger, J C and Crooks, L E and Kaufman, L and Watts, J C and Arakawa, M},
	month = sep,
	year = {1985},
	pmid = {4023236},
	keywords = {Blood Flow Velocity, Brain, Humans, Magnetic Resonance Spectroscopy},
	pages = {743--747}
}

@article{zhao_computer_2005,
	title = {Computer simulation studies of the effects of dynamic shimming on susceptibility artifacts in {EPI} at high field},
	volume = {173},
	issn = {1090-7807},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/15705507},
	doi = {10.1016/j.jmr.2004.11.009},
	abstract = {Dynamic shimming in multi-slice imaging aims to achieve optimal magnetic field homogeneity by updating the shim coil currents for each slice in real time. Dynamic shimming may reduce the signal loss and geometric distortion caused by magnetic susceptibility variations between tissues and is likely to be valuable for fast T2*-sensitive imaging techniques like EPI. A computer simulation of dynamic shimming using real image data has been developed to demonstrate the effectiveness of higher order dynamic shimming for echo planar imaging at high magnetic field, and to investigate the potential benefits of different orders of shim coil. Geometric distortions and signal intensities for different degrees of dynamic shimming were simulated and the results are compared with the images obtained with a conventional shimming technique. These results demonstrate the effectiveness, necessity and difficulty of high order dynamic shimming.},
	number = {1},
	urldate = {2011-01-03},
	journal = {Journal of Magnetic Resonance (San Diego, Calif.: 1997)},
	author = {Zhao, Yansong and Anderson, Adam W and Gore, John C},
	month = mar,
	year = {2005},
	pmid = {15705507},
	keywords = {Artifacts, Brain Mapping, Computer Simulation, Echo-Planar Imaging, Humans, Image Enhancement, Models, Statistical},
	pages = {10--22}
}

@article{dieringer_feasibility_2013,
	title = {Feasibility and benefit of using a cryogenic radiofrequency coil for functional cardiac magnetic resonance imaging of mice at 9.4 {T}},
	volume = {15},
	issn = {1097-6647},
	url = {http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3560191/},
	doi = {10.1186/1532-429X-15-S1-W39},
	number = {Suppl 1},
	urldate = {2013-05-21},
	journal = {Journal of Cardiovascular Magnetic Resonance},
	author = {Dieringer, B and Pohlmann, A and Dieringer, MA and Fuchs, K and Els, A and Waiczies, H and Waiczies, S and Schulz-Menger, J and Niendorf, T},
	month = jan,
	year = {2013},
	pmid = {null},
	pmcid = {PMC3560191},
	pages = {W39}
}

@article{gatehouse_applications_2005,
	title = {Applications of phase-contrast flow and velocity imaging in cardiovascular {MRI}},
	volume = {15},
	issn = {0938-7994, 1432-1084},
	url = {http://www.springerlink.com/content/x76u55054rkv57x2/},
	doi = {10.1007/s00330-005-2829-3},
	urldate = {2011-11-14},
	journal = {European Radiology},
	author = {Gatehouse, Peter D. and Keegan, Jennifer and Crowe, Lindsey A. and Masood, Sharmeen and Mohiaddin, Raad H. and Kreitner, Karl-Friedrich and Firmin, David N.},
	month = jul,
	year = {2005},
	pages = {2172--2184}
}

@article{summers_measurement_1997,
	title = {Measurement of flow in small vessels by magnetic resonance phase mapping techniques: anin vitro andin vivo study},
	volume = {5},
	issn = {1352-8661, 1352-8661},
	shorttitle = {Measurement of flow in small vessels by magnetic resonance phase mapping techniques},
	url = {http://rd.springer.com/article/10.1007%2FBF02592249?LI=true#page-1},
	doi = {10.1007/BF02592249},
	number = {2},
	urldate = {2013-02-04},
	journal = {Magma: Magnetic Resonance Materials in Physics, Biology, and Medicine},
	author = {Summers, P. E. and Parsons, S. R. and Taylor, M. G. and Deverall, P. B. and Padayachee, T. S.},
	month = jun,
	year = {1997},
	pages = {173--178}
}

@article{manke_model_2002,
	title = {Model evaluation and calibration for prospective respiratory motion correction in coronary {MR} angiography based on 3-{D} image registration},
	volume = {21},
	issn = {0278-0062},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/12564881},
	doi = {10.1109/TMI.2002.804428},
	abstract = {Image processing was used as a fundamental tool to derive motion information from magnetic resonance (MR) images, which was fed back into prospective respiratory motion correction during subsequent data acquisition to improve image quality in coronary MR angiography (CMRA) scans. This reduces motion artifacts in the images and, in addition, enables the usage of a broader gating window than commonly used today to increase the scan efficiency. The aim of the study reported in this paper was to find a suitable motion model to be used for respiratory motion correction in cardiac imaging and to develop a calibration procedure to adapt the motion model to the individual patient. At first, the performance of three motion models [one-dimensional translation in feet-head (FH) direction, three-dimensional (3-D) translation, and 3-D affine transformation] was tested in a small volunteer study. An elastic image registration algorithm was applied to 3-D MR images of the coronary vessels obtained at different respiratory levels. A strong intersubject variability was observed. The 3-D translation and affine transformation model were found to be superior over the conventional FH translation model used today. Furthermore, a new approach is presented, which utilizes a fast model-based image registration to extract motion information from time series of low-resolution 3-D MR images, which reflects the respiratory motion of the heart. The registration is based on a selectable global 3-D motion model (translation, rigid, or affine transformation). All 3-D MR images were registered with respect to end expiration. The resulting time series of model parameters were analyzed in combination with additionally acquired motion information from a diaphragmatic MR pencil-beam navigator to calibrate the respiratory motion model. To demonstrate the potential of a calibrated motion model for prospective motion correction in coronary imaging, the approach was tested in CMRA examinations in five volunteers.},
	number = {9},
	urldate = {2011-03-03},
	journal = {IEEE Transactions on Medical Imaging},
	author = {Manke, Dirk and Rösch, Peter and Nehrke, Kay and Börnert, Peter and Dössel, Olaf},
	month = sep,
	year = {2002},
	pmid = {12564881},
	keywords = {Adult, Artifacts, Calibration, Coronary Vessels, Humans, Image Processing, Computer-Assisted, Imaging, Three-Dimensional, Magnetic Resonance Angiography, Male, Motion, Respiration},
	pages = {1132--1141}
}

@article{lee_evaluation_2002,
	title = {Evaluation of a {Novel} {Doppler} {Index} of {Combined} {Systolic} and {Diastolic} {Myocardial} {Performance} in {Newfoundland} {Dogs} with {Familial} {Prevalence} of {Dilated} {Cardiomyopathy}},
	volume = {43},
	issn = {1740-8261},
	url = {http://onlinelibrary.wiley.com/doi/10.1111/j.1740-8261.2002.tb01663.x/abstract},
	doi = {10.1111/j.1740-8261.2002.tb01663.x},
	abstract = {A Doppler index of myocardial performance (IMP) has been recently proposed in human cardiology, which is calculated from the isovolumic contraction time (ICT), isovolumic relaxation time (IRT), and the ejection time (ET) using the following formula: (ICT+IRT)/ET. In this study, IMP was measured and evaluated in Newfoundland dogs categorized in four groups: Normal dogs (n = 31), dilated cardiomyopathy (DCM) (n = 34), depressed fractional shortening (dFS) (n = 27), and left ventricular enlargement (LVE) (n = 7). IMP was found to be independent of age, sex, body surface area, and the R-R interval in the Normal group. There were significant differences in IMP between the DCM group and the Normal and dFS groups (P {\textless} 0.05) and between Newfoundlands with overt vs. occult DCM. IMP is a Doppler index which appears to correlate with severity of disease and may be of use in the early diagnosis of affected dogs during screening for the presence of DCM.},
	language = {en},
	number = {2},
	urldate = {2013-08-12},
	journal = {Veterinary Radiology \& Ultrasound},
	author = {Lee, Byeong-Han and Dukes-McEwan, Joanna and French, Anne T. and Corcoran, Brendan M.},
	year = {2002},
	keywords = {Echocardiography, Newfoundland dogs, diastolic function, dilated cardiomyopathy, doppler index, familial dilated cardiomyopathy, occult dilated cardiomyopathy, systolic function},
	pages = {154--165}
}

@article{galiuto_contraction_1998,
	title = {Contraction and relaxation velocities of the normal left ventricle using pulsed-wave tissue {Doppler} echocardiography},
	volume = {81},
	issn = {0002-9149},
	abstract = {We designed the present study (1) to investigate the velocities of longitudinal movement of the human left ventricle by pulsed-wave tissue Doppler (PWTD) imaging; (2) to test the hypothesis that a heterogeneous pattern of longitudinal systolic and diastolic velocities exists among individual left ventricular wall segments; (3) to establish the range of this heterogeneity, and (4) to correlate the function of individual segments with the known orientation of myocardial fibers. PWTD is a novel ultrasound method to quantify myocardial contraction and relaxation velocities. In 27 young normal subjects, PWTD peak values of longitudinal systolic and diastolic velocities were measured for 12 left ventricular segments visualized from the apical window. The PWTD sampling of each myocardial segment resulted in a triphasic velocity curve during each cardiac cycle: a systolic velocity wave (S) directed toward the transducer, and an early diastolic (E) and a late diastolic (A) velocity wave away from the transducer. A heterogeneous pattern of systolic and diastolic myocardial velocities was observed between individual wall segments as well as for the basal and midsegments of each myocardial wall. The difference between the highest and lowest values for S was 38.4\% in the basal segments and 56.3\% in the midwall segments. The difference between low and high velocities for E was 61.4\% in the basal and 38.2\% in the midsegments; for A the difference was 29.5\% in the basal and 32.6\% in the midsegments. In general, lower velocity values were found in the septum with higher basal to midwall difference. The lateral and posterior walls had higher, but more uniform, velocities. PWTD enables the quantitative assessment of regional systolic and diastolic myocardial velocities. Substantial heterogeneity of velocities exists within individual myocardial segments, and must be taken into account in any clinical application. The observed heterogeneity in longitudinal function is consistent with the known spatial distribution of myocardial fibers.},
	language = {eng},
	number = {5},
	journal = {The American Journal of Cardiology},
	author = {Galiuto, L. and Ignone, G. and DeMaria, A. N.},
	month = mar,
	year = {1998},
	pmid = {9514459},
	keywords = {Adult, Echocardiography, Doppler, Female, Heart Ventricles, Humans, Male, Myocardial Contraction, Ventricular Function, Ventricular Function, Left},
	pages = {609--614}
}

@article{delfino_comparison_2006,
	title = {Comparison of myocardial velocities obtained with magnetic resonance phase velocity mapping and tissue {Doppler} imaging in normal subjects and patients with left ventricular dyssynchrony},
	volume = {24},
	issn = {1053-1807},
	doi = {10.1002/jmri.20641},
	abstract = {PURPOSE

To compare longitudinal myocardial velocity and time to peak longitudinal velocity obtained with magnetic resonance phase velocity mapping (MR-PVM) and tissue Doppler imaging (TDI), and to assess the reproducibility of each method.

MATERIALS AND METHODS

Longitudinal myocardial velocity was measured by TDI and MR-PVM in 10 normal volunteers and 10 patients with dyssynchrony. The reproducibility of MR-PVM and TDI was assessed on repeated measurements in the 10 normal volunteers.

RESULTS

MR and TDI measurements of longitudinal myocardial velocity correlated well (r = 0.86) in both normal subjects and patients with dyssynchrony. However, myocardial velocities measured with MR consistently exceeded velocities measured with TDI. MR and TDI agreed strongly in measuring the time to peak velocity (r = 0.97). The reproducibility of TDI and MR-PVM appeared similar in measuring peak velocities (13.1\% vs. 11.0\%, respectively; P = NS) and time to peak velocity (9.1\% vs. 5.7\%, respectively; P = NS).

CONCLUSION

Excellent correlation and reproducibility were observed between MR-PVM and TDI in measuring longitudinal myocardial velocity and time to peak velocity in both normal subjects and patients with dyssynchrony.},
	number = {2},
	journal = {Journal of magnetic resonance imaging: JMRI},
	author = {Delfino, Jana G and Bhasin, Mohit and Cole, Robert and Eisner, Robert L and Merlino, John and Leon, Angel R and Oshinski, John N},
	month = aug,
	year = {2006},
	pmid = {16786564},
	keywords = {Adult, Case-Control Studies, Echocardiography, Doppler, Female, Humans, Linear Models, Magnetic Resonance Imaging, Cine, Male, Reproducibility of Results, Time Factors, Ventricular Dysfunction, Left},
	pages = {304--311}
}

@article{martin_direct_1971,
	title = {Direct {Correlation} of {External} {Systolic} {Time} {Intervals} with {Internal} {Indices} of {Left} {Ventricular} {Function} in {Man}},
	volume = {44},
	issn = {0009-7322, 1524-4539},
	url = {http://circ.ahajournals.org/content/44/3/419},
	doi = {10.1161/01.CIR.44.3.419},
	abstract = {Direct correlation of externally measured systolic time intervals with internally measured indices was obtained using catheter-tip micromanometers in six patients who had normal coronary arteriograms. Simultaneous recordings were made of central aorta and left ventricular pressure, maximum rate of rise in left ventricular pressure (dp/dt), external carotid pulse, external and internal sound, and electrocardiogram. Acute interventions were used to vary the indices by a variety of mechanisms including changes in contractility, preload, afterload, and heart rate. The initial values and the changes in these values produced by acute interventions are identical for left ventricular ejection time (LVET) whether measured externally (range 175 to 385 msec) or internally (range 169 to 392), r = 0.99. Although the absolute values differed for internally measured isovolumic contraction time (internal ICT), externally measured ICT, and preejection time (PEP), there was good linear correlation between the changes observed in these values following the interventions. Changes in PEP and internal ICT showed excellent linear correlation (r = 0.94) and were also alike in absolute value following the interventions. The interval from the Q wave of the electrocardiogram to rise in left ventricular pressure (electrical-mechanical delay) did not change significantly during these interventions. During a period of spontaneous isorhythmic dissociation there was close tracking between beat-to-beat changes in PEP and internal ICT and between externally and internally measured LVET. Following acute interventions PEP and left ventricular dp/dt changed inversely.
Externally measured systolic time intervals have therefore been shown in man to correlate well with directly measured internal indices, both in steady-state conditions and during a series of acute interventions. This convenient and atraumatic method has been shown to be a valid and sensitive measure of myocardial performance.},
	language = {en},
	number = {3},
	urldate = {2013-10-31},
	journal = {Circulation},
	author = {Martin, C. Edwin and Shaver, James A. and Thompson, Mark E. and Reddy, P. Sudhakar and Leonard, James J.},
	month = sep,
	year = {1971},
	pmid = {5097444},
	keywords = {Electrical-mechanical delay, Isorhythmic dissociation, Isovolumic contraction time, Left ventricular dp/dt, Left ventricular ejection time, Preejection period},
	pages = {419--431},
	file = {Full Text PDF:/Users/cmey/Zotero/storage/9CG3ESFK/Martin et al. - 1971 - Direct Correlation of External Systolic Time Inter.pdf:application/pdf;Snapshot:/Users/cmey/Zotero/storage/DNZUVAVW/419.html:text/html}
}

@article{luk_pat_one-shot_1998,
	title = {One-shot spatially resolved velocity imaging},
	volume = {40},
	issn = {0740-3194},
	abstract = {For quantitative velocity measurement, we have developed a technique that acquires full velocity spectra without cardiac gating. After a cylindrical excitation restricts imaging to one spatial dimension, data are acquired while an oscillating gradient is played out. After each excitation, an image of velocity versus spatial location is obtained. For a given spatial location, a series of these images can be used to form an image of velocity versus time. Acquisition times are much shorter than for phase-contrast imaging or Fourier-encoded velocity imaging, obviating the need for cardiac gating. Although a two-shot version of this technique has been presented previously, we have developed a one-shot version that offers higher temporal resolution for a given velocity resolution and superior off-resonance properties.},
	language = {eng},
	number = {4},
	journal = {Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine},
	author = {Luk Pat, G. T. and Pauly, J. M. and Hu, B. S. and Nishimura, D. G.},
	month = oct,
	year = {1998},
	pmid = {9771577},
	keywords = {Aorta, Thoracic, Blood Flow Velocity, Humans, Magnetic Resonance Imaging, Models, Cardiovascular, Phantoms, Imaging, Signal Processing, Computer-Assisted},
	pages = {603--613}
}

@article{sharp_mri_2010,
	title = {{MRI} using radiofrequency magnetic field phase gradients},
	volume = {63},
	issn = {1522-2594},
	url = {http://onlinelibrary.wiley.com.gate2.inist.fr/doi/10.1002/mrm.22188/abstract},
	doi = {10.1002/mrm.22188},
	abstract = {Conventionally, MR images are formed by applying gradients to the main static magnetic field (B0). However, the B0 gradient equipment is expensive, power-hungry, complex, and noisy and can induce eddy currents in nearby conducting structures, including the patient. Here, we describe a new silent, B0 gradient-free MRI principle, Transmit Array Spatial Encoding (TRASE), based on phase gradients of the radio-frequency (RF) field. RF phase gradients offer a new method of k-space traversal. Echo trains using at least two different RF phase gradients allow spin phase to accumulate, causing k-space traversal. Two such RF fields provide one-dimensional imaging and three are sufficient for two-dimensional imaging. Since TRASE is a k-space method, analogues of many conventional pulse sequences are possible. Experimental results demonstrate one-dimensional and two-dimensional RF MRI and slice selection using a single-channel, transmit/receive, 0.2 T, permanent magnet, human MR system. The experimentally demonstrated spatial resolution is much higher than that provided by RF receive coil array sensitivity encoding alone but lower than generally achievable with B0 gradients. Potential applications are those in which one or more of the features of simplified equipment, lower costs, silent MRI, or the different physics of the image formation process are particularly advantageous. Magn Reson Med, 2010. © 2009 Wiley-Liss, Inc.},
	language = {en},
	number = {1},
	urldate = {2011-12-21},
	journal = {Magnetic Resonance in Medicine},
	author = {Sharp, Jonathan C and King, Scott B},
	month = jan,
	year = {2010},
	keywords = {MRI, RF phase gradient, TRASE, low field, radiofrequency},
	pages = {151--161}
}

@article{kayser_right_2000,
	title = {Right ventricular function in patients after acute myocardial infarction assessed with phase contrast {MR} velocity mapping encoded in three directions},
	volume = {11},
	issn = {1053-1807},
	abstract = {The purpose of the study was to assess global and regional myocardial function of the right ventricle (RV) with the use of phase contrast (PC) velocity mapping in patients after acute myocardial infarction. We examined 8 patients after acute myocardial wall infarction and 10 healthy volunteers for comparison. PC velocity mapping was performed in a single midventricular short-axis slice with velocity encoding in three different directions. RV displacement during systole in the through-plane direction differed significantly between patients and volunteers (P = 0.009). RV myocardial velocity in the through-plane and radial directions, evaluated at time of peak ejection rate, was significantly lower in patients than in healthy volunteers (P{\textless}0.05). RV abnormalities may be detected in patients after acute myocardial infarction using PC velocity mapping with velocity encoding in three different directions. Owing to their short acquisition times and relatively easy postprocessing, PC techniques are time-efficient and promising tools for the evaluation of RV function.},
	language = {eng},
	number = {5},
	journal = {Journal of magnetic resonance imaging: JMRI},
	author = {Kayser, H W and van der Geest, R J and van der Wall, E E and Duchateau, C and de Roos, A},
	month = may,
	year = {2000},
	pmid = {10813855},
	keywords = {Adult, Female, Humans, Image Processing, Computer-Assisted, Magnetic Resonance Imaging, Male, Middle Aged, Myocardial Infarction, Ventricular Function, Right},
	pages = {471--475}
}

@article{burkart_volumetric_1993,
	title = {Volumetric {Flow} {Rates} in the {Portal} {Venous} {System}: {Measurement} with {Cine} {Phase}-{Contrast} {MR} {Imaging}.},
	volume = {160},
	issn = {0361-803X, 1546-3141},
	shorttitle = {Volumetric flow rates in the portal venous system},
	url = {http://www.ajronline.org/content/160/5/1113},
	abstract = {The purposes of this study were to (1) validate the accuracy of cine phase-contrast MR flow measurements within the portal vein, (2) develop a suitable protocol for using this method to measure volumetric flow rate in the portal venous system, and (3) use this protocol, with Doppler sonography as a reference, to measure portal venous flow in healthy volunteers and in patients with protal venous hypertension.
Flow determinations were obtained in a model of fluid movement approximating blood-flow conditions in the portal venous system. A suitable protocol was based on consideration of the theoretical effects of (1) spatial resolution, (2) obliquity of the imaging plane to the direction of flow, and (3) signal-to-noise ratio of the signed quantitative velocity images (in three volunteers) on the accuracy and precision of flow measurements. This protocol was used to obtain cine phase-contrast MR images of the portal venous system in five volunteers and six patients.
Values obtained with a flow phantom showed good accuracy of cine phase-contrast-measured vs actual volumetric flow rate (r = .995; p = .0001; MR rate = [0.94 x actual rate] + 65.6 ml/min; standard error of the y estimate = 67.3 ml/min). Velocity encoding and section thickness substantially influenced the signal-to-noise ratio of the velocity images, whereas flip angle and matrix size had only minimal effect. In volunteers and patients, portal volumetric flow rates determined by using MR images and Doppler sonography showed good correlation (r = .94; p = .0003).
Our results indicate that cine phase-contrast MR imaging is a practical noninvasive method for measuring volumetric flow rates in the portal venous system.},
	language = {en},
	number = {5},
	urldate = {2012-04-17},
	journal = {American Journal of Roentgenology},
	author = {Burkart, D J and Johnson, C D and Morton, M J and Wolf, R L and Ehman, R L},
	month = may,
	year = {1993},
	pages = {1113--1118}
}

@article{frigo_design_2005,
	title = {The {Design} and {Implementation} of {FFTW}3},
	volume = {93},
	issn = {0018-9219},
	url = {http://dx.doi.org/10.1109/JPROC.2004.840301},
	abstract = {FFTW is an implementation of the discrete Fourier transform (DFT) that adapts to the hardware in order to maximize performance. This paper shows that such an approach can yield an implementation that is competitive with hand-optimized libraries, and describes the software structure that makes our current FFTW3 version flexible and adaptive. We further discuss a new algorithm for real-data DFTs of prime size, a new way of implementing DFTs by means of machine-specific single-instruction, multiple-data (SIMD) instructions, and how a special-purpose compiler can derive optimized implementations of the discrete cosine and sine transforms automatically from a DFT algorithm.},
	number = {2},
	urldate = {2012-05-04},
	journal = {Proceedings of the IEEE},
	author = {Frigo, M and Johnson, SG},
	month = feb,
	year = {2005},
	keywords = {maths, numerics},
	pages = {216--231}
}

@article{sadek_respiratory_1996-1,
	title = {Respiratory and postprandial changes in portal flow rate: assessment by phase contrast {MR} imaging},
	volume = {6},
	issn = {1053-1807},
	shorttitle = {Respiratory and postprandial changes in portal flow rate},
	abstract = {The objective of this study was to investigate the variability of several different phase contrast (PC) magnetic resonance techniques and duplex Doppler imaging (DDI) for measuring portal flow rate (PFR) with different patterns of respiration before and after a standard meal. PFR was measured in nine normal volunteers in both fasting and postprandial states, using both 2D and cine PC MR techniques. Two-dimensional PC technique was performed with and without breath-hold (BH). Four different patterns of BH (relaxed maximal inspiration, expiration, Valsalva maneuver, and Müller or reversed Valsalva) were used. Cine PC technique was performed without BH. DDI measurement of PFR was done in the fasting state with relaxed inspiration. PFR measurements made by means of PC MR techniques varied, depending on BH method, and were systematically less than those obtained by DDI. PFR measured during inspiration was significantly less than that measured during expiration and other respiratory maneuvers (P {\textless} .03). PFR increased significantly after a meal for PC and Doppler measurements, with a range of mean increases of 24 to 74\%. Two-dimensional PC MR imaging techniques yielded differing measurements of PFR, depending on whether they were done with or without BH, as well as on the pattern of BH. PC mean measures of PFR were consistently less than those of DDI. The physiologic inspiratory decreases and postprandial increases of the PFR were evident from 2D and cine PC MRI techniques, as well as with DDI.},
	number = {1},
	journal = {Journal of magnetic resonance imaging: JMRI},
	author = {Sadek, A G and Mohamed, F B and Outwater, E K and El-Essawy, S S and Mitchell, D G},
	month = feb,
	year = {1996},
	pmid = {8851411},
	keywords = {Adult, Eating, Female, Humans, Magnetic Resonance Angiography, Magnetic Resonance Imaging, Cine, Male, Portal Vein, Regional Blood Flow, Respiration},
	pages = {90--93}
}

@article{sa_vertical_2010,
	title = {Vertical distribution of specific ventilation in normal supine humans measured by oxygen-enhanced proton {MRI}},
	volume = {109},
	issn = {1522-1601},
	url = {http://www.ncbi.nlm.nih.gov.gate2.inist.fr/pubmed/20930129},
	doi = {10.1152/japplphysiol.00220.2010},
	abstract = {Specific ventilation (SV) is the ratio of fresh gas entering a lung region divided by its end-expiratory volume. To quantify

license: MIT

license_type: permissive

branch_name: refs/heads/master

extension: bib