Su1288 Real-Time Tissue Elastography: Non-Invasive Evaluation for Liver Fibrosis in Chronic Liver Disease Due to HCV

Background/Aim: Real-time tissue elastography (RTE) is a new non-invasive method for measurement of tissue elasticity that can be integrated with a conventional ultrasound system. The purpose of this study was to evaluate the diagnostic efficacy of RTE for severe hepatic fibrosis in patients with hepatitis C virus (HCV) by comparing with findings of histological fibrosis obtained by biopsy or hepatic resection. Materials/Methods: Sixty-two patients with HCV, and 2 with normal liver and liver tumors (metastasis and angiomyolipoma) were evaluated by RTE, as well as liver biopsy or hepatectomy. Seventeen healthy volunteers without fatty liver, viral hepatitis, and/or alcohol abuse underwent RTE as the normal control group. RTE was performed through the right intercostals space to observe right lobe using an EUP-L52 linear probe (3-7 MHz) and US scanner (Preirus, Hitachi Aloka Medical, Ltd, Tokyo) equipped with image analysis software, and probe was slightly held to detect the strain by heart beat. Color data inside the ROI were converted to relative strain values and features of the RTE image, then liver fibrosis index (LF index) was calculated using 9 factors of relative strain value and RTE image features (Fujimoto K. Kanzo 2010, Shiina T. Jpn J Appl Phys 2012). Azan stained liver specimens were scanned using a VS-100 (OLYMPUS corporation, Tokyo) and evaluated for hepatic fibrosis by METAVIR score. The percentage of fibrosis area in the specimen (%FA) was calculated with binary imaging using WinRoof (MITANI CO.Ltd, Tokyo), an integrated software system for image measurement, with a personal computer. Severe fibrosis was defined as F3 and F4. Previously proposed noninvasive prediction methods [FIB-4 (Vallet-Pichard A. Hepatol 2007) and APRI(Wai CT. Hepatol 2003)] were used for calculation, and the results compared with LF index. A receiver operating characteristic curve (ROC) was also calculated for each non-invasive method of estimation of hepatic fibrosis. RESULTS: Values for area under the ROC for LF index, APRI, and FIB-4 were 0.89, 0.80, and 0.85, respectively. Based on the ROC finding, the cut-off value for prediction of severe fibrosis using LF index was determined to be greater than 2.8. Accuracy rate, sensitivity, and specificity of prediction for severe fibrosis were 87.7%, 81.2%, and 93.0%, respectively, whereas those for APRI were 63.0%, 36.8%, and 86.0%, respectively, and for FIB-4 were 76.5%, 65.8%, and 86.0%, respectively. LF index showed not only good accuracy for predicting severe fibrosis, but also a good relationship to %FA (r=0.319, P=0.01) as compared with FIB-4 (r=0.235, P=0.06). Although a significant relationship was also observed for APRI (r=0.322, P=0.01), the accuracy rate was worse than with LF index. CONCLUSION: RTE is a new sensitive and effective method for predicting severe fibrosis (F3 and F4) in patient with HCV.