Compartment model analysis of intravenous contrast-enhanced dynamic computed tomography in hepatic hemodynamics: A validation study using intra-arterial contrast-enhanced computed tomography.

Abstract

To verify the utility of the 2-in-1-out-compartment model analysis (CMA) of intravenous contrast-enhanced dynamic computed tomography (IV-CT) for evaluating hepatic arterial and portal venous flow using intra-arterial contrast-enhanced CT (IA-CT). We retrospectively evaluated 49 consecutive patients who underwent IV-CT and were radiologically or histologically diagnosed as having hepatic malignant lesion (51 classical hepatocellular carcinomas [HCC], 4 early HCC, 3 cholangiolocellular carcinomas, 1 mixed HCC, 3 cholangiocellular carcinomas). As a gold standard for hepatic arterial and portal blood flows, we defined the normalized enhancement in CT values on CTAP (nCTAP) and CTHA (nCTHA). The hepatic arterial (k1a ) and portal venous inflow velocity (k1p ) constants in hepatic lesions and surrounding liver parenchyma were obtained from the CMA of IV-CT with various outflow velocity constant (k2 ) limits using the nonlinear least square method. The correlation coefficient between the normalized enhancement in IA-CT and CMA of IV-CT was statistically evaluated according to various k2 limits. The highest mean correlation coefficient between k1a and nCTHA (r = 0.65, P < 0.0001) was observed when k2 ≦0.035. The highest mean correlation coefficient between k1p and nCTAP (r = 0.69, P < 0.0001) was observed when k2 ≦0.045. The decrease in correlation coefficient was significant when the upper k2 limit was lower than 0.03 or higher than 0.07 compared to the best mean correlation coefficient (P < 0.05). Hepatic arterial and portal venous flows can be evaluated quantitatively to some extent with appropriate outflow velocity constant limits using the CMA of IV-CT.