Shear Wave Elastography for Assessment of Liver Fibrosis in Chronic Hepatitis: Pilot Work

Abstract

Background and Aim: Shear wave elastography (SWE) is a novel ultrasound technique used for detecting liver fibrosis in patients of chronic hepatitis (CH). Assessment of fibrosis is based on the liver stiffness assessed both in qualitative and quantitative manner. We evaluated CH patients [hepatitis B (CHB), hepatitis C (CHC)] and compared the results with the reference method of liver biopsy. Methods: CH patients scheduled for liver biopsy, underwent SWE on the same day. SWE was performed on Supersonic-Imagine Ultrasound (US) machine with patient lying supine, right arm in maximum abduction. B-Mode US image of right lobe liver was acquired through the right intercostal space. SWE mode was turned on and SWE box was placed in the liver at a depth of 3–5 cm from the liver capsule, avoiding the intrahepatic vessels. After ensuring image stabilization, a color image of different types of stiffness was obtained. Increasing fibrosis was depicted by deep blue color to red. Quantification was then performed by choosing a circle (15–20 mm diameter) preferably in the central area of the SWE box, exhibiting a homogeneous color map display. Six liver stiffness values (maximum, minimum, mean) per patient were taken at different segments of the right lobe. Mean stiffness value was correlated with Metavir histological grading (F0–F4). Results: Ten CH patients (9CHB, 1CHC) were evaluated. On SWE, qualitative and quantitative assessment, different mean values of liver stiffness were recorded (range 4.7 kPa to 18.7 kPa). On correlation with Metavir score, F0, F1, F2, F3 and F4 grade of liver fibrosis was diagnosed in two patients each respectively. Conclusion: SWE is a reliable diagnostic tool for the evaluation of liver fibrosis. Larger studies are required for establishing SWE cut off values for diagnosing different grades of fibrosis in Indian patients of CH.