Comparison of R2 correction methods for accurate fat quantification in fatty liver

Purpose: To compare the performance of fat fraction quantification using single‐R2* and dual‐R2* correction methods in patients with fatty liver, using MR spectroscopy (MRS) as the reference standard. Materials and Methods: From a group of 97 patients, 32 patients with hepatic fat fraction greater than 5%, as measured by MRS, were identified. In these patients, chemical shift encoded fat‐water imaging was performed, covering the entire liver in a single breathhold. Fat fraction was measured from the imaging data by postprocessing using 6 different models: single‐ and dual‐R2* correction, each performed with complex fitting, magnitude fitting, and mixed magnitude/complex fitting to compare the effects of phase error correction. Fat fraction measurements were compared with co‐registered spectroscopy measurements using linear regression. Results: Linear regression demonstrated higher agreement with MRS using single‐R2* correction compared with dual‐R2* correction. Among single‐R2* models, all 3 fittings methods performed similarly well (slope = 1.0 ± 0.06, r2 = 0.89–0.91). Conclusion: Single‐R2* modeling is more accurate than dual‐R2* modeling for hepatic fat quantification in patients, even in those with high hepatic fat concentrations. J. Magn. Reson. Imaging 2013;37:414–422. © 2012 Wiley Periodicals, Inc.