Non-invasive monitoring of hepatic steatosis via acoustic structure quantification of ultrasonography with MR spectroscopy as the reference standard

PURPOSE: The purpose of this study was to prospectively evaluate whether monitoring hepatic steatosis by ultrasonography with acoustic structure quantification (ASQ) is feasible, using magnetic resonance spectroscopy (MRS) as the reference standard. METHODS: Thirty-six patients with suspected fatty liver disease underwent both untrasonography with ASQ and MRS on the same day. After a mean follow-up period of 11.4±2.5 months, follow-up ultrasonography with ASQ and MRS were performed on 27 patients to evaluate whether hepatic steatosis had improved. The focal disturbance (FD) ratio, as calculated using ASQ, and the hepatic fat fraction (HFF), estimated by MRS, were obtained at both initial and follow-up examinations. Pearson correlation coefficients were calculated to assess the correlations between ordinal values. RESULTS: The FD ratio showed a strong, negative linear correlation with the HFF after logarithmic transformation of both variables from the initial examinations of 36 patients (ρ=-0.888, P<0.001) and the follow-up examinations of 27 patients (ρ=-0.920, P<0.001). There was also a significant, negative linear correlation between the change in the logarithm of the FD ratio and the change in the logarithm of the HFF by MRS over the follow-up period (ρ=-0.645, P<0.001). In 16 patients with an increased FD ratio on follow-up, the HFF on follow-up MRS significantly decreased, and high-density lipoprotein levels significantly increased, whereas low-density lipoprotein levels tended to decrease. CONCLUSION: The FD ratio was significantly correlated with the HFF at both the initial and follow-up examinations, and there was also a significant correlation between changes in the FD ratio and changes in the HFF over the follow-up period.