Contrast Enhancement Characteristics of Hepatocellular Carcinoma on Two-Phase Dynamic Scan with Spiral CT

PURPOSE: The purpose.of this study was to characterize the enhancing patterns of hepatocellular carcinoma (HCC) on two-phase dynamic incremental liver scan with spiral CT. MATERIALS AND METHODS: Two-phase dynamic incremental liver scan using spiral CT was performed on 230 lesions in 107 patients with HCC. CT scanning was performed with a table speed of 13mm/sec and a section thickness of 10 mm;120 mL of contrast medium was injected intravenously with a automatic injector at the rate of 3mL/sec. CT scans were started 35 sec(early phase) and 3 min(delayed phase) after beginning injection of contrast medium. The tumors were divided into 2 groups according to size(< or = 3cm and > 3cm), the contrast enhancement patterns of HCCs and capsules in the early and delayed phases were analyzed in each group. RESULTS: Most of HCCs appeared as high-attenuating lesions in the early phase(75% in tumors smaller than 3cm and 61% in tumors larger than 3cm), and as low-attenuating lesions in the delayed phase(68% in tumors smaller than 3cm and 90% in tumors larger than 3cm). Forty-eight percent of HCCs smaller than 3cm and 58% of HCCs larger than 3cm were high-attenuating in the early phase and low-attenuating in the delayed phase. Thirty-two percent of capsules were low- or iso-attenuating in the early phase and high-attenuating in the delayed phase. Capsules were demonstrated in 22% in HCCs smaller than 3cm and 67% in HCCs larger than 3 cm(p <. 01). CONCLUSION: Two-phase dynamic scan with spiral CT is useful in the diagnosis of HCC because of a precise display of hemodynamic characteristics of HCCs.