Detection of hepatocellular carcinoma with multi-slices sprial CT by using double-arterial phase and portal venous phase enhanced scanning

Objective: To evaluate the double-arterial phase and portal venous phase scanning in the detection of hepatocellular carcinoma with multi-slice sprial CT (MSCT). Methods: Ninety-four patients with hepatocellular carcinoma were examined by abdominal plain CT and early arterial phase (EAP), late arterial phase (LAP), portal venous phase (PVP). Contrast agent of 100 ml (300 mg I/ml) was administrated intravenously by 3 ml/s, for scanning of EAP at 20 to 22 s, LAP at 34 to 37s, and PVP at 60 s. Chi-square test was carried out to compare the sensitivity among various phases. Results: A total of 318 lesions was detected pathologically, with 86 lesions less than 3 cm in size and 232 lesions more than 3 cm. For the early arterial phase, late arterial and portal venous phase, the sensitivity was 39.5% (34), 67.4% (58), 44.2% (38) respectively for the small tumors, which showed significant differences between phases(χ2=15.38,P<0.01). For the large tumors, the sensitivity was 89.6% (208), 99.6% (231), 99.1% (230), respectively(χ2=39.09,P<0.01). All had positive predictive values of 100%. If the tumors were taken together, the sensitivity was 76.1% (242), 90.9% (289), 84.3% (268), and the positive predictive value was 88.3% (242/274), 86.3% (289/335), 93.7% (268/286) for the early arterial phase, late arterial and portal venous phase respectively. There was significant difference of sensitivity and positive predictive value between phases (χ2=25 62, 9.29, P<0.05). Conclusion: Double-arterial phase could improve the detection of tumors, especially for small hepatocellular carcinoma, and late arterial phase scanning is particularly important. (authors)