T1 Independent, T2* Corrected Chemical Shift Based Fat-Water Separation With Multi-peak Fat Spectral Modeling Is an Accurate and Precise Measure of Hepatic Steatosis

Purpose: To determine the precision and accuracy of hepatic fat-fraction measured with a chemical shift-based MRI fat-water separation method, using single-voxel MR spectroscopy (MRS) as a reference standard. Materials and Methods: In 42 patients, two repeated measurements were made using a T-1-independent, T-2*-corrected chemical shift-based fat-water separation method with multi-peak spectral modeling of fat, and T-2-corrected single voxel MR spectroscopy. Precision was assessed through calculation of Bland-Altman plots and concordance correlation intervals. Accuracy was assessed through linear regression between MRI and MRS. Sensitivity and specificity of MRI fat-fractions for diagnosis of steatosis using MRS as a reference standard were also calculated. Results: Statistical analysis demonstrated excellent precision of MRI and MRS fat-fractions, indicated by 95% confidence intervals (units of absolute percent) of [-2.66%, 2.64%] for single MRI ROI measurements, [-0.81%, 0.80%] for averaged MRI ROI, and [-2.70%, 2.87%] for single-voxel MRS. Linear regression between MRI and MRS indicated that the MRI method is highly accurate. Sensitivity and specificity for detection of steatosis using averaged MRI ROI were 100% and 94%, respectively. The relationship between hepatic fat-fraction and body mass index was examined. Conclusion: Fat-fraction measured with T-1-independent T-2*-corrected MRI and multi-peak spectral modeling of fat is a highly precise and accurate method of quantifying hepatic steatosis.