Usefulness of Arrival Time Parametric Imaging in Evaluating the Degree of Liver Disease Progression in Chronic Hepatitis C Infection

Objective To determine whether the degree of liver disease progression in chronic hepatitis C infection can be evaluated by arrival time parametric imaging using contrast‐enhanced sonography with Sonazoid (perfluorobutane; GE Healthcare, Oslo, Norway). Methods In this study, 60 patients with liver disease in chronic hepatitis C infection were examined and compared with 10 healthy volunteers who served as controls. A recommended dose of the sonographic contrast agent Sonazoid was intravenously infused, and the S5 or S6 region of the liver and right kidney were observed concurrently while movies of the procedure were saved. Arrival time parametric images of liver parenchymal blood flow were created, with red pixels to indicate an arrival time of 0 to 5 seconds and yellow pixels to indicate an arrival time of 5 to 10 seconds. From the obtained images, the ratio of the red area to the entire enhanced area of the liver was calculated using image‐processing software. Each participant was subsequently subjected to liver biopsy for liver fibrosis staging according to Metavir scores, and the determined fibrosis stage was compared with the ratio of red. The serum albumin level, platelet count, and prothrombin time were also compared with the ratio of red for each participant. Results The ratio of red increased significantly as liver fibrosis stage advanced (P < .01 for F1 versus F2; P < .01 for F1 versus F3; P < .01 for F1 versus F4; and P < .01 for F2 versus F4). As the ratio of red increased, significant decreases were observed in the serum albumin level (r = −0.29; P = .027), platelet count (r = −0.46; P = .0003), and prothrombin time (r = −0.46; P = .0002). Conclusions Arrival time parametric imaging using Sonazoid‐enhanced sonography enables noninvasive evaluation of the degree of progression of liver disease in chronic hepatitis C infection and is thus considered clinically useful.