Hepatic lipid accumulation in healthy subjects:: A comparative study using spectral fat-selective MRI and volume-localized 1H-MR spectroscopy

Fat-selective MRI was applied to assess the amount and spatial distribution of hepatic lipids (HL) in healthy subjects. The results were compared with those obtained by localized H-1-MR spectroscopy (MRS). Ninety subjects (23-63 years old) underwent single-slice fat-selective MRI with spatial-spectral excitation and volume-localized spectroscopy at 1.5 T. HLs were analyzed in ventral and dorsal regions of interest (ROIs) of the liver in fat-selective images. Spectra were evaluated using the integral signal of methylene and methyl signals. The fat-selective images showed smooth and homogeneous distribution of HL over the entire cross section of the liver. There was, however, a marked interindividual variability in the amount of HL. MRS revealed a lipid signal fraction between 0.5% and 39.3%. The fat content in the ROIs in images correlated well with the spectroscopic results (r >= 0.95). Both techniques provide sufficient sensitivity for a reliable and quantitative assessment of liver steatosis in subjects without liver disease. H-1-MRS has a higher sensitivity compared to MRI, especially for small amounts of HL, which may be of interest for metabolic interventions. Fat-selective images provide more spatial information about fat distribution, which makes this technique suitable for clinical imaging of patients with liver disease.