Noninvasive quantitation of human liver steatosis using magnetic resonance and bioassay methods

Abstract

The purpose was to evaluate the ability of three magnetic resonance (MR) techniques to detect liver steatosis and to determine which noninvasive technique (MR, bioassays) or combination of techniques is optimal for the quantification of hepatic fat using histopathology as a reference. Twenty patients with histopathologically proven steatosis and 24 control subjects underwent single-voxel proton MR spectroscopy (MRS; 3 voxels), dual-echo in phase/out of phase MR imaging (DEI) and diffusion-weighted MR imaging (DWI) examinations of the liver. Blood or urine bioassays were also performed for steatosis patients. Both MRS and DEI data allowed to detect steatosis with a high sensitivity (0.95 for MRS; 1 for DEI) and specificity (1 for MRS; 0.875 for DEI) but not DWI. Strong correlations were found between fat fraction (FF) measured by MRS, DEI and histopathology segmentation as well as with low density lipoprotein (LDL) and cholesterol concentrations. A Bland-Altman analysis showed a good agreement between the FF measured by MRS and DEI. Partial correlation analyses failed to improve the correlation with segmentation FF when MRS or DEI data were combined with bioassay results. Therefore, FF from MRS or DEI appear to be the best parameters to both detect steatosis and accurately quantify fat liver noninvasively.

Regional differences in hepatic fat fractions in over- weight children and adolescents observed by 3T 1H-MR spectroscopy

“…Nevertheless, regional differences in HFF up to 12% obtained in the present study are not controversial to the biopsy results [13,25,26] .…”

“…Szczepaniak et al [19] found a CV=11% for 10 subjects. The average CV calculated for spectroscopy volumes in three different positions was 12% for 20 steatosis patients and 24 control subjects [13] . Cowin et al [11] found different CV depending on volume position in the liver for a group of 6 subjects: CV=3% in right lobe, posterior; CV=7% in right lobe, anterior; CV=6% in right lobe, central; CV=13% in left lobe.…”

“…Precision of 10% was reported for determination of hepatic HFF by visual histological examination in steatosis patients [13] .…”

“…Correlation between MRI and histology makes it possible to identify the steatosis grade based on 1H MRS results by linear dependency or by calibration graph [13,14,28] . d'Assignies et al [13] found average HFF= 47.5±19.6 % measured by visual histology and average HFF=18.1±9 % measured by 1H MRS in 20 steatosis patients.…”

“…"Within liver" variability of HFF has been studied in groups of adults ranging from 6 to 77 subjects [11][12][13][14] . The aim of the present study was to examine the variability of the HFF in a large group of overweight and obese children and adolescents.…”