Accuracy of Ultrasonography and Different CT Techniques in Diagnosis and Grading of Hepatic Steatosis in Chronic Hepatitis C Virus Patients

Abstract

Objective: This study aims to assess the diagnostic utility of ultrasonography and which methods of measuring attenuation on computed tomography scans is best for detection and grading of hepatic fat content in patients with chronic hepatitis C virus (HCV) infection. Materials and Methods: This study included 65 patients, withchronic hepatitis C virus infection, who had liver biopsies as a part of pre-requirement for interferon therapy. All patients submitted to ultrasound; non enhanced and enhanced CT. Attenuation measurements were obtained from 3 regions of interest in the liver and three in the spleen on both unenhanced and portal phase contrast-enhanced CT images. Hepatic attenuation measurements were analyzed both with and without normalization with the spleen. Normalization included both differences and ratios between hepatic and splenic attenuation values. Average attenuation values of the liver were compared with pathologic fat content, as were the differences and ratios between hepatic and splenic attenuation values. Results: Ultrasound had a sensitivity of 76% and specificity 73.3% in the diagnosis of hepatic steatosis. Also ultrasound accurately graded 41 out of the 65 (63.1%) patients included in the study. The simple measurement of hepatic attenuation on non enhanced CT (CTL) had the best parameters for diagnosis of hepatic steatosis with sensitivity 83%, specificity 93.3% and positive predictive value (PPV) 97.6%. All series of R2 values for the unenhanced CT scans were higher than those for the contrast-enhanced images. The R2 values for simple liver attenuation measurement without comparison with splenic attenuation were higher than the values in which splenic measurements were considered. Conclusion: Ultrasound and non enhanced CT can be used as screening tools for detection of hepatic steatosis in patients with chronic hepatitis C virus patients. Simple measurement of hepatic attenuation on unenhanced CT is more accurate than differential liver spleen values. Also, unenhanced CT can differentiate between mild-moderate and severe steatosis.