Magnetic resonance for quantitative assessment of liver steatosis: a new potential tool to monitor antiretroviral-drug-related toxicities

Background: There is an increasing need for new diagnostic tools to monitor antiretroviral drug-related toxicities. Magnetic resonance (MR) imaging and MR spectroscopy are non-invasive diagnostic methods used in the detection and quantification of liver fat. The aim of this study was to compare sensitivity and specificity of different MR techniques in the quantitative assessment of liver steatosis, using liver biopsy as the reference standard, in patients with and without HIV infection. Methods: Sequentially evaluated patients with suspected steatosis who were referred for liver biopsy at our tertiary care site were eligible. MR liver fat content (LFC) was estimated by T2-weighted and fat-suppressed T2-weighted spin-echo, dual-phase T1-weighted gradient-echo, multiecho gradient-echo and H-1 spectroscopy. Association between LFC and histological steatosis percentage was calculated by using univariate linear regressions and Pearson's coefficient. Respective receiver operating characteristic (ROC) curves were used to compare specificity and sensitivity of MR methods in diagnosis (cutoff 5%) and in quantitative evaluation (cutoff 33%) of steatosis. Results: A total of 28 patients were identified: 12 refused or had contraindications for liver biopsy and 16 had biopsies plus MR. LFC and histological steatosis percentage were strongly associated (fat-suppressed r= 0.86 [P< 0.001], dual-phase r= 0.88 [P< 0.001], multiecho r= 0.95 [P< 0,001] and spectroscopy r= 0.84 [P= 0.01]). MR techniques had high sensitivity and specificity in diagnosis and quantitative assessment of steatosis (areas under ROC curves ranging from 0.88 to 0.98). Conclusions: This pilot study confirms that MR may be a sensitive non-invasive alternative to biopsy for the quantitative assessment of liver fat and a potential end point to monitor antiretroviral-drug-related toxicities.