Abstract No. 187: Impact of C-Arm CT on Treatment Planning in Patients Undergoing Chemembolization for Tumors Located in Segments with Watershed Arterial Supply

Abstract

To evaluate the impact of C-arm CT on treatment algorithms in patients undergoing chemoembolization for hepatocellular carcinoma (HCC) in regions that have dual or variable arterial supply (segment IV, segment I, medial portions of segments VII and V, referred to as watershed regions). From March to July 2008, 14 patients (39-78 years old, mean 61.7 years) with HCC in watershed regions underwent chemoembolization. Mean tumor diameter was 2.5 cm (range 1 cm - 5.7 cm). Non-contrast and selective arterially- enhanced C-arm CT acquisitions (8 second rotational scan of ∼200 degrees) with 3D reconstruction were obtained in addition to conventional digital subtraction angiograms (DSA) in all patients. Impact on diagnosis and treatment was categorized as: a) identification of additional lesions not seen on DSA; b) evaluation of completeness of ethiodol uptake in the tumor and need for additional selective catheterization and chemoembolization; c) depiction of multiple arteries supplying the tumor and identification of the dominant vessel; and/or d) facilitation of selective catheterization of complex vascular anatomy. All cases were technically successful. C-arm CT had a significant impact on the treatment plan in 9 of the 14 patients (64.3%). In 4 patients (28.6%), the tumor(s) was not conspicuous on DSA, but was identified on C-arm CT, allowing accurate targeting. C-arm CT identified incomplete target embolization due to dual arterial supply to the tumor in five patients (35.7%) that was not apparent on DSA, leading to additional catheterization and embolization to complete treatment. In one patient (7.1%), C-arm CT was crucial in delineating the segmental arterial vessels supplying the tumor and providing 3D mapping for successful catheterization. C-arm CT has become a crucial tool in the diagnosis and treatment of patients undergoing chemoembolization for HCCs located in watershed regions and exceeds the capabilities of DSA in a majority of the patients.