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Volumetric abdominal perfusion measurement using a pseudo‐randomly sampled 3D fast‐spin‐echo (FSE) arterial spin labeling (ASL) sequence and compressed sensing reconstruction
Author(s) -
Taso Manuel,
Zhao Li,
Guidon Arnaud,
Litwiller Daniel V.,
Alsop David C.
Publication year - 2019
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.27761
Subject(s) - compressed sensing , sampling (signal processing) , acceleration , image quality , iterative reconstruction , undersampling , computer science , nuclear medicine , algorithm , physics , artificial intelligence , computer vision , medicine , image (mathematics) , filter (signal processing) , classical mechanics
Purpose To improve image quality and spatial coverage for abdominal perfusion imaging by implementing an arterial spin labeling (ASL) sequence that combines variable‐density 3D fast‐spin‐echo (FSE) with Cartesian trajectory and compressed‐sensing (CS) reconstruction. Methods A volumetric FSE sequence was modified to include background‐suppressed pseudo‐continuous ASL labeling and to support variable‐density (VD) Poisson‐disk sampling for acceleration. We additionally explored the benefits of center oversampling and variable outer k‐space sampling. Fourteen healthy volunteers were scanned on a 3T scanner to test acceleration factors as well as the various sampling schemes described under synchronized‐breathing to limit motion issues. A CS reconstruction was implemented using the BART toolbox to reconstruct perfusion‐weighted ASL volumes, assessing the impact of acceleration, different reconstruction, and sampling strategies on image quality. Results CS acceleration is feasible with ASL, and a strong renal perfusion signal could be observed even at very high acceleration rates (≈15). We have shown that ASL k‐space complex subtraction was desirable before CS reconstruction. Although averaging of multiple highly accelerated images helped to reduce artifacts from physiologic fluctuations, superior image quality was achieved by interleaving of different highly undersampled pseudo‐random spatial sampling patterns and using 4D‐CS reconstruction. Combination of these enhancements produces high‐quality ASL volumes in under 5 min. Conclusions High‐quality isotropic ASL abdominal perfusion volumes can be obtained in healthy volunteers with a VD‐FSE and CS reconstruction. This lays the groundwork for future developments toward whole abdomen free‐breathing non‐contrast perfusion imaging.