Role of diffusion-weighted imaging in evaluating therapeutic efficacy after transcatheter arterial chemoembolization for hepatocellular carcinoma

Abstract

The decision to repeat transcatheter arterial chemo-embolization (TACE) for hepatocellular carcinoma (HCC) is based on correct evaluation of response to therapy. The purpose of this study was to investigate whether apparent diffusion coefficient (ADC), a quantitative parameter of diffusion-weighted imaging (DWI), can predict early HCC recurrence after TACE. Results obtained using this method were compared with those using iodized-oil computed tomography (CT). DWI was performed on 25 patients with 36 HCCs before and 5-7 days after TACE to calculate the ADC of HCC. Patients were also evaluated with iodized-oil CT immediately after TACE. Contrast-enhanced CT was performed 3 months after TACE to confirm early relapse of HCC lesion. After TACE, the percent change in ADC (%ADC) from before to after therapy was significantly increased in non-relapsed lesions (85.2±12.4%) compared to relapsed lesions (8.0±56.7%, p=0.0004). However, no difference in area under the curve was seen for receiver operating characteristic analysis to predict early relapse after TACE between %ADC from DWI (95% confidence interval, 0.743-1.026) and iodized-oil CT (95% confidence interval, 0.703-1.016). ADC from DWI can evaluate the efficacy of TACE for HCC as effectively as iodized-oil CT, and may help in deciding whether to repeat TACE.