MRI-based fat quantification of the liver: Is it time for commercially available products?

Abstract

Purpose: (1) To assess the clinical applicability of commercially available solutions for MR-based quantification of the hepatic fat fraction (HFF) and (2) to compare their results with clinically established in-phase/oppose-phase (IP/OP) imaging as proposed by Dixon.

Methods: Twenty-eight patients underwent MRI examinations using multigradient-echo sequences including multi-peak modeling and T₂^∗ correction, IP/OP imaging and multi-echo spectroscopy with successive HFF evaluation. Histopathological examination yielded the fraction of adipose hepatocytes (fAH) and the presence of increased liver iron concentration (LIC). We correlated HFF with fAH, and assessed concordance correlations among the MR-based methods with the presence of increased LIC as a control parameter. We investigated the liver segmentation quality and overall workflow of the postprocessing solutions (Philips LiverHealth and Siemens LiverLab).

Results: IP/OP imaging yielded a very strong correlation (r=0.88) with fAH when excluding three cases with increased LIC. Multigradient echo imaging and multiecho spectroscopy quantifications yielded similar correlations (r=0.87…0.93) as IP/OP imaging but were insensitive to increased LIC. Visceral fat, kidney tissue and major vessels were included regularly in the segmentation. Spectroscopic fat quantification was sensitive to the inclusion of visceral fat.

Conclusions: IP/OP imaging allows HFF quantification when ruling out hepatic siderosis, whereas dedicated multi-echo imaging sequences and spectroscopy show no bias for increased iron concentration. The segmentation quality and workflow of both postprocessing solutions need to be improved. Nevertheless, all solutions are able to bring MRI-based hepatic fat quantification into the clinical application. We therefore recommend commercial hepatic fat quantification tools for institutions specialised to abdominal imaging.

Keywords: Chemical shift imaging; Fatty Liver; Liver fat quantification; Magnetic resonance spectroscopy.