Free-breathing fat and R * quantification in the liver using a stack-of-stars multi-echo acquisition with respiratory-resolved model-based reconstruction.

TitleFree-breathing fat and R * quantification in the liver using a stack-of-stars multi-echo acquisition with respiratory-resolved model-based reconstruction.
Publication TypeJournal Article
Year of Publication2020
AuthorsSchneider M, Benkert T, Solomon E, Nickel D, Fenchel M, Kiefer B, Maier A, Chandarana H, Block KTobias
JournalMagn Reson Med
Volume84
Issue5
Pagination2592-2605
Date Published2020 11
ISSN1522-2594
KeywordsBreath Holding, Humans, Liver, Magnetic Resonance Imaging, Non-alcoholic Fatty Liver Disease, Respiration
Abstract

PURPOSE: To develop a free-breathing hepatic fat and quantification method by extending a previously described stack-of-stars model-based fat-water separation technique with additional modeling of the transverse relaxation rate .

METHODS: The proposed technique combines motion-robust radial sampling using a stack-of-stars bipolar multi-echo 3D GRE acquisition with iterative model-based fat-water separation. Parallel-Imaging and Compressed-Sensing principles are incorporated through modeling of the coil-sensitivity profiles and enforcement of total-variation (TV) sparsity on estimated water, fat, and parameter maps. Water and fat signals are used to estimate the confounder-corrected proton-density fat fraction (PDFF). Two strategies for handling respiratory motion are described: motion-averaged and motion-resolved reconstruction. Both techniques were evaluated in patients (n = 14) undergoing a hepatobiliary research protocol at 3T. PDFF and parameter maps were compared to a breath-holding Cartesian reference approach.

RESULTS: Linear regression analyses demonstrated strong (r > 0.96) and significant (P ≪ .01) correlations between radial and Cartesian PDFF measurements for both the motion-averaged reconstruction (slope: 0.90; intercept: 0.07%) and the motion-resolved reconstruction (slope: 0.90; intercept: 0.11%). The motion-averaged technique overestimated hepatic values (slope: 0.35; intercept: 30.2 1/s) compared to the Cartesian reference. However, performing a respiratory-resolved reconstruction led to better value consistency (slope: 0.77; intercept: 7.5 1/s).

CONCLUSIONS: The proposed techniques are promising alternatives to conventional Cartesian imaging for fat and quantification in patients with limited breath-holding capabilities. For accurate estimation, respiratory-resolved reconstruction should be used.

DOI10.1002/mrm.28280
Alternate JournalMagn Reson Med
PubMed ID32301168
PubMed Central IDPMC7396291
Grant ListP41 EB017183 / EB / NIBIB NIH HHS / United States
R01 EB018308 / EB / NIBIB NIH HHS / United States
Related Institute: 
MRI Research Institute (MRIRI)

Weill Cornell Medicine
Department of Radiology
525 East 68th Street New York, NY 10065