Hepatic Steatosis in Morbidly Obese Patients Undergoing Gastric Bypass Surgery: Assessment With Open-System 1H-MR Spectroscopy

OBJECTIVE. The purpose of this study was to assess, with histopathologic control, the use of open-system 1-T 1H MR spectroscopy for the evaluation of hepatic steatosis in morbidly obese patients undergoing gastric bypass surgery. SUBJECTS AND METHODS. Patients underwent 1H MR spectroscopy (MRS) for the assessment of steatosis before and 3 months after surgery. Liver biopsy was performed during surgery. Hepatic steatosis was expressed as the ratio of fat peak area to cumulative water and fat peak areas. Histopathologic percentage of steatosis was graded as none (0–5%), mild (5–33%), moderate (33–66%), or severe (> 66%). The accuracy of 1H-MRS and Spearman correlation coefficient were calculated. Differences between groups were assessed with the Wilcoxon signed rank and Mann-Whitney tests. RESULTS. The study included 38 patients (median age, 45.5 years; median body mass index, 47.7). Before surgery, median steatosis measured with 1H-MRS was 5.8%. The accuracy of 1H-MRS was 89% (32/36), and the 1H-MRS findin...