Gavin Hamilton1, Alexandra N Schlein1, Adrija Mamidipalli1, Michael S Middleton1, Rohit Loomba2, and Claude B Sirlin1
1Department of Radiology, University of California, San Diego, San Diego, CA, United States, 2Department of Medicine, University of California, San Diego, San Diego, CA, United States
To estimate hepatic proton density fat fraction (PDFF), MRI
techniques acquire multi-echo, gradient-echo images, assuming the R2* of fat
and water to be identical. Liver MRS spectra were fitted with constraints
derived from those used in MRI to examine this assumption. We compared fat R2*eff
(the effective fat R2* that would be measured by MRI) with water R2* and found
that water R2* and fat R2*eff were correlated. There was no significant
difference between water R2* and fat R2*eff, supporting the
assumption that when measuring PDFF using MRI, fat and water R2* can be treated
as identical.
