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To propose respiratory motion-informed locally low-rank reconstruction (MI-LLR) for robust free-breathing single-bolus quantitative 3D myocardial perfusion CMR imaging. Simulation and in-vivo results are compared to locally low-rank (LLR) and compressed sensing reconstructions (CS) for reference.Data were acquired using a 3D Cartesian pseudo-spiral in-out k-t undersampling scheme (R = 10) and reconstructed using MI-LLR, which encompasses two stages. In the first stage, approximate displacement fields are derived from an initial LLR reconstruction to feed a motion-compensated reference system to a second reconstruction stage, which reduces the rank of the inverse problem. For comparison, data were also reconstructed with LLR and frame-by-frame CS using wavelets as sparsifying transform (Improved uniformity of MBF maps with reduced local variations was achieved with MI-LLR. For rest and stress, intra-volunteer variation of absolute and relative MBF was lower in MI-LLR (±0.17 mL/g/min [26%] and ±1.07 mL/g/min [33%]) versus LLR (±0.19 mL/g/min [28%] and ±1.22 mL/g/min [36%]) and versusThe combination of pseudo-spiral Cartesian undersampling and dual-stage MI-LLR reconstruction improves free-breathing quantitative 3D myocardial perfusion CMR imaging under rest and stress condition.

Purpose In this study, an iterative k-t principal component analysis (PCA) algorithm with nonrigid frame-to-frame motion correction is proposed for dynamic contrast-enhanced three-dimensional perfusion imaging. Methods An iterative k-t PCA algorithm was implemented with regularization using training data corrected for frame-to-frame motion in the x-pc domain. Motion information was extracted using shape-constrained nonrigid image registration of the composite of training and k-t undersampled data. The approach was tested for 10-fold k-t undersampling using computer simulations and in vivo data sets corrupted by respiratory motion artifacts owing to free-breathing or interrupted breath-holds. Results were compared to breath-held reference data. Results Motion-corrected k-t PCA image reconstruction resolved residual aliasing. Signal intensity curves extracted from the myocardium were close to those obtained from the breath-held reference. Upslopes were found to be more homogeneous in space when using the k-t PCA approach with motion correction. Conclusions Iterative k-t PCA with nonrigid motion correction permits correction of respiratory motion artifacts in three-dimensional first-pass myocardial perfusion imaging. Magn Reson Med 72:68–79, 2014. © 2013 Wiley Periodicals, Inc.

In k-t sensitivity encoding (SENSE), MR data acquisition performed in parallel by multiple coils is accelerated by sparsely sampling the k-space over time. The resulting aliasing is resolved by exploiting spatiotemporal correlations inherent in dynamic images of natural objects. In this article, a modified k-t SENSE reconstruction approach is presented, which aims at improving the temporal fidelity of first-pass, contrast-enhanced myocardial perfusion images at high accelerations. The proposed technique is based on applying parallel imaging on the training data in order to increase their spatial resolution. At a net acceleration of 5.8 (k-t factor = 8, training profiles = 11) accurate representations of dynamic signal-intensities were achieved. The efficacy of this approach as well as limitations due to noise amplification were investigated in computer simulations and in vivo experiments. (c) 2009 Wiley-Liss, Inc.

Three-dimensional myocardial perfusion imaging requires significant acceleration of data acquisition to achieve wholeheart coverage with adequate spatial and temporal resolution. The present article introduces a compartment-based k-t principal component analysis reconstruction approach, which permits three-dimensional perfusion imaging at 10-fold nominal acceleration. Using numerical simulations, it is shown that the compartment-based method results in accurate representations of dynamic signal intensity changes with significant improvements of temporal fidelity in comparison to conventional k-t principal component analysis reconstructions. Comparison of the two methods based on rest and stress threedimensional perfusion data acquired with 2.3 3 2.3 3 10 mm 3 during a 225 msec acquisition window in patients confirms the findings and demonstrates the potential of compartmentbased k-t principal component analysis for highly accelerated three-dimensional perfusion imaging. Magn Reson Med 65:575–587, 2011. V C 2010 Wiley-Liss, Inc.

In k-t sensitivity encoding (SENSE), MR data acquisition performed in parallel by multiple coils is accelerated by sparsely sampling the k-space over time. The resulting aliasing is resolved by exploiting spatiotemporal correlations inherent in dynamic images of natural objects. In this article, a modified k-t SENSE reconstruction approach is presented, which aims at improving the temporal fidelity of first-pass, contrast-enhanced myocardial perfusion images at high accelerations. The proposed technique is based on applying parallel imaging on the training data in order to increase their spatial resolution. At a net acceleration of 5.8 (k-t factor = 8, training profiles = 11) accurate representations of dynamic signal-intensities were achieved. The efficacy of this approach as well as limitations due to noise amplification were investigated in computer simulations and in vivo experiments.

An approach to efficiently measure three dimensional velocity vector fields and turbulent kinetic energy of blood flow is presented. Multipoint phase contrast imaging is used in combination with Bayesian analysis to map both mean and fluctuating velocities over a large dynamic range and for practically relevant signal to noise ratios. It is demonstrated that the approach permits significant spatiotemporal undersampling to allow for clinically acceptable scan times. Using numerical simulations and in vitro measurements in aortic valve phantoms it is shown that for given scan time Bayesian multipoint velocity encoding provides consistently lower errors of velocity and turbulent kinetic energy over a larger dynamic range relative to previous methods. In vitro significant differences in both peak velocity and turbulent kinetic energy between the aortic CoreValve (150 cm/s 293 J/m(3) ) and the St. Jude Medical mechanical valve (120 cm/s 149 J/m(3) ) were found. Comparison of peak turbulent kinetic energy measured in a patient with aortic stenosis (950 J/m(3) ) and in a patient with an implanted aortic CoreValve (540 J/m(3) ) revealed considerable differences relative to the values detected in healthy subjects (149 ± 12 J/m(3) ) indicating the potential of the method to provide a comprehensive hemodynamic assessment of valve performance in vivo.