Optimal phases of dynamic CT for detecting hepatocellular carcinoma: evaluation of unenhanced and triple-phase images

Background: To determine the optimal phases of dynamic computed tomography (CT) for detecting hepatocellular carcinoma (HCC). Methods: Fifty-two patients with 85 HCC Modules were examined by means of u nenhanced and triple-phase CT images of the whole liver. The time for obtai ning the arterial-phase images was 25-55 s after intravenous bolus injectio n of contrast material, the time for obtaining the portal venous-phase imag es was 65-100 s, and the time for obtaining late-phase images was 145 s to 4 min. Detectability of the HCC nodules for all phases was statistically co mpared. Results: The detection rates for the arterial- and late-phase images were s ignificantly higher than for the unenhanced and portal venous-phase images (p < 0.01). The combination of arterial- and late-phase images showed the s ame number of HCC nodules in the same number of patients as did the combina tion of unenhanced and triple-phase images. Conclusion: The combination of the arterial- and late-phase imagings was be st for detecting HCC nodules.