Is Unenhanced Computed Tomography Reliable in the Assessment of Macrovesicular Steatosis in Living Liver Donors?

Abstract

In this retrospective study, we aimed to determine the diagnostic value of unenhanced computed tomography in the assessment of macrovesicular steatosis in potential living liver transplant donors by using biopsy as a reference standard. This retrospective study was approved by our institutional review board, and all included patients provided written informed consent. Our study group included 181 donor candidates (mean age of 35.9 ± 9.3 y) who underwent unenhanced computed tomography and subsequent needle biopsy (mean period after scan of 12.74 d) in the right hepatic lobe (at least 2 samples per patient). Histologic degree of macrovesicular steatosis was determined. A radiologist with 10 years of experience assessed steatosis ofthe right hepatic lobe by using 2 methods: (1) a 4-point visual grading system that used attenuation comparison between the liver and hepatic vessels and (2) the liver attenuation index, which was calculated with region of interest measurements of hepatic attenuation. We used statistical analyses to compare accuracy in the diagnosis of macrovesicular steatosis. Our study population was divided into 3 groups according to histologic steatosis grade. Group 1 consisted of 157 candidates with 0% to 5% steatosis, group 2 consisted of 11 candidates with 6% to 15% steatosis, and group 3 consisted of 13 candidates with 16% to 100% steatosis. Mean liver attenuation (in Hounsfield units ± standard deviation) was 58.93 ± 5.07 for group 1, 47.8 ± 4.17 for group 2, and 39.11 ± 6.5 for group 3. Significant differences in liver attenuation were observed between groups using one-way analyses of variance (F = 107307; P < .01). For visual grading, correlation coefficient for computed tomography was 0.959. Unenhanced computed tomography to assess liver attenuation represents an objective and noninvasive means for detection of hepatic steatosis. This method can prevent unnecessary biopsies.