Assessment of Intra-Hepatocellular Lipid Content using Magnetic Resonance Spectroscopy

Excessive accumulation of intra-hepatocellular lipid (IHCL) can lead to one of the most common forms of chronic liver diseases in adults, the non-alcoholic fatty liver disease (NAFLD) that comprises of a range of liver disorders including hepatic steatosis, an advanced stage of which can result in liver cirrhosis. Many diseases are known to be associated with the retention of IHCL including, but not limited to, obesity and type II diabetes. It is, thus, essential to quantify IHCL for early diagnosis and monitoring for an effective treatment. This study presents a non-invasive, robust and reproducible approach to quantify IHCL content using the single-voxel 1H magnetic resonance spectroscopy (MRS) at 3 Tesla (3T). For validation, peanut oil phantoms of known fat fractions (8%, 14%, 18%, 25%, 30%, 40%, 45%, 55%) were constructed and tested. For in vivo scans, the study included fifteen obese volunteers. Spectroscopy was performed at three different voxel locations and fat fractions were evaluated after T2 correction was done using five echo times (24, 30, 35, 40, 50 milliseconds). The results with the peanut oil phantoms were in close agreement with the known fat fraction values (<10% error on the fat fraction value). The in-vivo study used T2 correction for accuracy and provided valuable insight on nonuniformity in IHCL content in liver right lobe by taking three voxel locations into account. Altogether, the study demonstrated a reliable and accurate way to quantify liver fat content through spectroscopy at 3T.