Comparison of R(2) * Correction Methods for Accurate Fat Quantification in Fatty Liver

Horng DE, Hernando D, Hines CD, Reeder SB

PURPOSE: To compare the performance of fat fraction quantification using single-R(2) * and dual-R(2) * 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-R(2) * 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-R(2) * correction compared with dual-R(2) * correction. Among single-R(2) * models, all 3 fittings methods performed similarly well (slope = 1.0 ± 0.06, r(2) = 0.89-0.91).

CONCLUSION: Single-R(2) * modeling is more accurate than dual-R(2) * modeling for hepatic fat quantification in patients, even in those with high hepatic fat concentrations. J. Magn. Reson. Imaging 2012;. © 2012 Wiley Periodicals, Inc.