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

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.