Baseline and early MR apparent diffusion coefficient quantification as a predictor of response of unresectable hepatocellular carcinoma to doxorubicin drug-eluting bead chemoembolization

Purpose To investigate baseline and early apparent diffusion coefficients (ADC) derived from diffusion-weighted imaging (DWI) as a predictor of objective response (OR) and survival in unresectable hepatocellular carcinoma (HCC) treated with doxorubicin drug-eluting bead (DEB) transcatheter arterial chemoembolization. Materials and Methods In a prospective study, 57 patients underwent DEB chemoembolization. Dynamic contrast-enhanced magnetic resonance imaging and DWI were performed at baseline and 1 and 3 months after DEB chemoembolization. OR was evaluated per modified Response Evaluation Criteria In Solid Tumors (mRECIST) and European Association for the Study of the Liver (EASL) guidelines. Baseline ADCs of tumors that showed OR at 1 and 3 months were compared with nonresponding tumor ADCs by two-sample t test and receiver operating characteristic curves. Additionally, ADC changes at 30 days were correlated with OR. Finally, Kaplan-Meier analysis was used to compare survival between patients with lesions demonstrating more restricted baseline diffusion and others. Results At 1 month, 33 patients (60%) showed OR (21 complete responses and 12 partial responses). At baseline, tumors with OR at 1 month showed significantly more restricted diffusion (0.731 × 10^-3 mm²/s) compared with others (1.057 × 10^-3 mm²/s; P =.031). No difference between response rates at 1 and 3 months according to mRECIST and EASL was observed. For an area under the curve of 0.965, the sensitivity and specificity of predicting objective tumor response at 1 month using a baseline HCC ADC of 0.83 × 10^-3 mm²/s were 91% and 96%, respectively. In addition, patients with lesions with a baseline ADC < 0.83 × 10^-3 mm²/s showed prolonged survival compared with others (P <.001). Conclusions In unresectable HCC, a baseline ADC < 0.83 × 10^-3 mm²/s is a predictor of survival and treatment response at 1 and 3 months after DEB chemoembolization with high sensitivity and specificity.