Medical Physics Seminar – Monday, October 26, 2020
Motion compensation and distortion correction in liver diffusion MRI
Annie Zhang
Conventional liver diffusion MRI acquisitions suffer from several challenges including low spatial resolution, B0-induced distortions, and elastic motion-induced signal voids. In this work, a motion-robust liver diffusion-weighted imaging (DWI) technique was proposed and evaluated by using the optimized moment-nulled gradient waveform. Motion-robust and distortion-corrected liver diffusion-weighted imaging (DWI) was further enabled by combining optimized motion-compensated diffusion waveforms with multi-shot EPI acquisitions.
Cardiac 4D Flow MRI: Validation, Post-Processing, and Application in Clinical Studies
Philip Corrado
Time-resolved, volumetric, velocity-encoded MRI (“4D flow MRIâ€) allows for comprehensive assessment of intracardiac blood flow, but poor sensitivity to slow flow and long post-processing times limit its clinical utility. We address those limitations in two studies: In the first, we use benchtop experimentation with optical imaging in a phantom to pick the optimal strategy for imaging slow flow in the heart. In the second, we evaluate the use of deep learning for automatic left and right ventricular segmentation to dramatically speed up the post-processing of cardiac 4D flow images and improve inter-observer repeatability. Finally, we demonstrate the utility of cardiac 4D flow MRI to probe flow in a population with poorly understood intracardiac hemodynamics: young adults born premature.