Can triphasic hepatic multislice CT validate the LI-RADS treatment response algorithm after trans-catheter arterial chemoembolization treatment of hepatocellular carcinoma?

Background Our aim is to evaluate LI-RADS-TR algorithm and its ability to assess the viability of TACE-treated HCC. We prospectively evaluated 100 patients with known HCC, treated with TACE and came for follow-up to assess therapy response and to plan the next step in treatment using triphasic CT study. Imaging response was evaluated according to LI-RADS-TR algorithm and compared to modified Response Evaluation Criteria in Solid Tumors (mRECIST) arterial phase hyperenhancement (APHE) criterion. Reference standard for “viable” tumors in treated observations included presence of strong tumor hyperenhancement in arterial phase and washout in the delayed phase which also shows dense accumulation of iodized oil in the target lesion. Results When equivocal observations were considered as LR-TR viable, LR-TR viable resulted in 92.31% sensitivity, 83.33% specificity and 88% accuracy. On the other side when equivocal observations were considered as LR-TR nonviable, it resulted in 84.62% while the specificity increased to 100% with increased accuracy (92%). The mRECIST criteria for viable tumors (presence of APHE) showed sensitivity of 84.62% and specificity of 75%. mRECIST and LR-TR sensitivities were the same when equivocal lesions were considered as nonviable and lower mRECIST than LR-TR when equivocal lesions were considered as viable, while specificities were higher in LR-TR viable being 100% when equivocal lesions were considered as nonviable, 83.33% when equivocal lesions were considered as viable and 75% in mRECIST-viable. Conclusions LR-TR algorithm showed good diagnostic performance compared to mRECIST, with high specificity and sensitivity when equivocal lesions were considered as nonviable, as well as improved accuracy.