Triple-phase computed tomography during arterial portography with bolus tracking for hepatic tumors

Purpose. The purpose of this study was to assess the usefulness of triple-phase computed tomography during arterial portography ( CTAP) using a bolus-tracking technique. Material and methods. The subjects were 60 patients with hepatic tumors: 20 patients with metastatic liver tumors with a normal liver and 40 with hypervascular hepatocellular carcinoma (HCC) with liver cirrhosis. The region of interest was set in the portal vein, and CTAP was automatically started after the triggering threshold ( 180 HU) was reached. Three scans were performed: early phase ( E), hepatic parenchymal phase ( HP), and late phase ( L). The scan start time of E-CTAP was measured. The detection rates of the HCC nodules were evaluated during each CTAP phase. Results. CTAP was performed by bolus tracking without failure in any of the patients. The mean scan start times in the normal liver group and liver cirrhosis group were 14.3 +/- 1.34 s and 18.5 +/- 2.46 s, respectively, which were significantly different from each other. The detection rates of HCC nodules for E-CTAP, HP-CTAP, and L-CTAP were 29.6%, 100%, and 83.3%, respectively. Conclusion. The bolus-tracking technique enabled us to perform CTAP with optimal timing regardless of the portal blood flow dynamics.