Early Detection of Local RFA Site Recurrence Using Total Liver Volume Perfusion CT: Initial Experience

Rationale and Objectives. The aim of this study was to prospectively evaluate the feasibility of a novel total liver volume perfusion computed tomographic technique in demonstrating treatment-site recurrence of liver metastases after radiofrequency ablation (RFA). Materials and Methods. Eleven patients considered to be at increased risk for local RFA-site tumor recurrence underwent both positron emission tomography (PET) and perfusion computed tomography (CTP): a 12-phase scan of the entire liver acquired before and 11 times after contrast injection. After coregistration, blood flow maps were created using the maximum slope method. Results. In all cases, the CTP-derived blood flow maps fully paralleled the PET images in showing either the absence (nine of 13 lesions) or presence (four of 13 lesions) of local RFA-site recurrence. Marginal lesions with high hepatic arterial perfusion (>50 mL/min/100 g) and low portal venous perfusion (< 10 mL/min/100 g) represented recurring vital tumor tissue (P < .05). Conclusion. Total liver volume CTP seems feasible for the detection and localization of treatment-site recurrence after RFA.