Su2030 Hepatocytes Migration Into Both Portal and Hepatic Vein During Radiofrequency Ablation in Porcine Liver

Introduction: Triphasic contrast-enhanced CT (CE-CT) demonstrating tumor hypervascularity on arterial phase (AP) followed by a washout pattern on portal venous phase (PVP) and/ or delayed phase (DP) is the characteristic feature underlying the imaging diagnosis of hepatocellular carcinomas (HCCs). However, this typical vascular feature is not always present, especially in small tumors of 200 ng/ml with a background of chronic liver disease. Mean attenuation in Hounsfield units (HU) were measured by placing regions of interest on tumors and surrounding liver. Hypervascularity of tumor were quantitatively defined by either AP(T-L) ,representing the conventional criteria that considers the attenuation difference between tumor (T) and surrounding liver (L) in AP, or T(AP-UE) ,representing the proposed criteria that compares the attenuation difference of tumor in AP to that of UE-CT. The cut-off criterion for tumor hypervascularity was quantitatively evaluated at 5 and 10HU. Result: T(AP-UE) identifiedmore tumor hypervascularity as compared to AP(T-L) at cut-off of 5HU (96% vs. 65%, p 2 to <4 cm (97/97% vs. 87/74%, p<0.001) and ≥ 4 cm (96/89% vs. 48/36%, p<0.001) when a cut-off of 5/10HU were used. Conclusion: UE-CT in combination with CE-CT can increase sensitivity of hypervascularity detection in HCC than CE-CT alone. A quantitative approach for the characterization of hypervascularity is feasible and may enhance detection and decrease operator-dependent variability. The use of UE-CT may enhance CECT detection of HCCs as per American Association for Study of Liver Disease (AASLD) / European Association for the Study of Liver (EASL) / Asian Pacific Association for the Study of the Liver (APASL) imaging criteria.