Distortionless, free‐breathing, and respiratory resolved 3D diffusion weighted imaging of the abdomen

作者：Philip K. Lee, Xuetong Zhou, Nan Wang, Ali Syed, Ryan L. Brunsing, Shreyas Vasanawala, Brian A. Hargreaves · 发表于：Magnetic Resonance in Medicine · 年份：2024 · DOI：10.1002/mrm.30067 · 被引用次数：4 · 研究领域：Advanced Neuroimaging Techniques and Applications、MRI in cancer diagnosis、Advanced MRI Techniques and Applications

PURPOSE: Abdominal imaging is frequently performed with breath holds or respiratory triggering to reduce the effects of respiratory motion. Diffusion weighted sequences provide a useful clinical contrast but have prolonged scan times due to low signal-to-noise ratio (SNR), and cannot be completed in a single breath hold. Echo-planar imaging (EPI) is the most commonly used trajectory for diffusion weighted imaging but it is susceptible to off-resonance artifacts. A respiratory resolved, three-dimensional (3D) diffusion prepared sequence that obtains distortionless diffusion weighted images during free-breathing is presented. Techniques to address the myriad of challenges including: 3D shot-to-shot phase correction, respiratory binning, diffusion encoding during free-breathing, and robustness to off-resonance are described. METHODS: A twice-refocused, M1-nulled diffusion preparation was combined with an RF-spoiled gradient echo readout and respiratory resolved reconstruction to obtain free-breathing diffusion weighted images in the abdomen. Cartesian sampling permits a sampling density that enables 3D shot-to-shot phase navigation and reduction of transient fat artifacts. Theoretical properties of a region-based shot rejection are described. The region-based shot rejection method was evaluated with free-breathing (normal and exaggerated breathing), and respiratory triggering. The proposed sequence was compared in vivo with multishot DW-EPI. RESULTS: The proposed sequence exhibi...