Transarterial Chemoembolization of HCC with Radiopaque Microspheres: Evaluation with Computed Tomography and the Complementary Role of Contrast-Enhanced Ultrasonography.

Purpose: To assess the diagnostic performance of computed tomography (CT), and of the combination of CT with contrast-enhanced ultrasonography (CT + CEUS), for the early evaluation of local response of hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE) with radiopaque drug-eluting microspheres (RO-DEMs).

Materials And Methods: 30 HCC patients (55 target tumors) were treated with TACE with RO-DEMs (diameter: 70-150 μm) preloaded with 75 mg doxorubicin/2 ml of microspheres. Unenhanced and contrast-enhanced CT, followed by CEUS, were performed 1-3 days post-RO-DEMs-TACE. Contrast-enhanced magnetic resonance (MR) performed 1 month later served as the reference standard. Local tumor response was evaluated with modified Response Evaluation Criteria in Solid Tumors (mRECIST).

Results: MR diagnosed 9 tumors with complete response and 46 with residual disease. Compared to MR, CT had 9 false negative and 1 false positive diagnosis for residual tumor. Potential causes for these misdiagnoses were the hyperdensities and associated artifacts (caused by the accumulation of RO-DEMs in the target tumors) and the small size of residual tumor. CT + CEUS had 3 false negative and no false positive diagnosis for residual tumor. The sensitivity, specificity and diagnostic accuracy of CT for detection of residual tumor were, respectively: 80.4%, 88.9% and 81.8%, and for CT + CEUS: 93.5%, 100% and 94.5%, respectively. Agreement (kappa coefficient) in application of mRECIST between MR and CT was lower than between MR and CT + CEUS (0.508 vs. 0.757).

Conclusion: CT evaluation of TACE with RO-DEMs is associated with limitations which can be partially overcome by combining CT with CEUS.