Compartmental Analysis of R2 measurements of Hepatic Lipid & Iron In Vivo using Breath-Hold Multi-Echo 1H Spectroscopy (HISTO)

Puneet Sharma¹, Hiroumi D. Kitajima¹, Xiaodong Zhong², Bobby Kalb³, Diego R. Martin³

Multi-echo T2-corrected MR spectroscopy (HISTO-MRS) is technique known to accurately measure lipid fraction in the liver. The ability for HISTO-MRS to distinguish water and lipid components, in addition to measuring individual T2, allows the concurrent estimation of hepatic iron content. This study presents in vivo data to support the findings from controlled phantoms studies, which demonstrate high positive correlation of R2_water with iron, but relative insensitivity for R2_fat. These observations suggest a water-compartmental dependence on hepatic iron deposition. Conversely, MRI-derived R2* showed sensitivity to hepatic lipid in addition to iron, which can obscure estimations of hepatic iron/lipid in combined disease.