Abstract No. 512 Intraarterial computed tomography–enhancement mapping for response assessment of hepatocellular carcinoma to transarterial chemoembolization: a preliminary analysis

Abstract

To evaluate the feasibility and accuracy of utilizing intra-arterial computed tomography (IACT)–based enhancement mapping (EM) in predicting response of hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE). This single-institution retrospective study included 16 patients (mean age, 66 years, range, 50-77). IACT protocol consisted of two sets of CT scans (non-contrast and intra-arterial contrast-enhanced acquisitions) performed before and after chemoembolic delivery on a hybrid Angio-CT System. After procedure completion, IACT data were processed offline with dedicated EM software (Hepacare, Siemens Healthineers, Germany) which utilizes high-resolution deformable registration and subtraction for residual arterial tumor enhancement assessment. Analysis was done on the full resolution data with an isotropic voxel size of 0.6 mm3. Areas of residual enhancement above the post-chemoembolization background noise level were considered as residual disease. Quantification of these areas within the treated HCC was used to assess individual tumor response according to mRECIST. Study objectives were technical feasibility and accuracy of EM in predicting HCC response by mRECIST on the first routine cross-sectional contrast-enhanced CT or MR imaging (FUI-1) after TACE. EM was successfully performed in 14 (87.5%) patients (2 patients: suboptimal contrast-enhanced IACT due to catheter dislodgment). Mean time from TACE to FUI-1 was 9.5 weeks. Among the 14 patients successfully analyzed with EM, 21 HCCs were treated with TACE (mean diameter, 2.5 cm [range 1-6.3]; mean number of HCCs per patient, 1.5 [range 1-3]). Tumor response prediction based on EM showed complete response in 19 (86%) and partial response in 3 (14%) of HCCs, respectively. Response assessment by FUI-1 fully agreed with EM response assessment for all 21 HCCs treated with TACE. Dedicated EM using the proposed IACT imaging protocol was feasible and highly accurate in predicting response after TACE. Further studies are warranted to validate and investigate the role of this method for intraprocedural immediate response assessment and subsequent decision making.