Multidetector CT with double arterial phase and high-iodine-concentration contrast agent in the detection of hepatocellular carcinoma.

Purpose: The purpose of this study was to determine whether the double arterial phase with multidetector computed tomography MDCT and high-iodine-concentration contrast material (CM) improves identification of hepatocellular carcinoma (HCC).
Materials and Methods: Fifty patients with 111 HCC foci (61 confirmed histologically, 46 confirmed by percutaneous interventional procedures, four confirmed by CT follow-up of at least 6 months) underwent MDCT with a double arterial phase and a portal venous phase after administration of contrast material with a high iodine concentration (400 mgI/ml, 2 ml/kg, 5 ml/s). Two radiologists independently evaluated the images in three distinct reading sessions (early arterial phase (EAP), late arterial phase (LAP) and double arterial phase) to determine presence, number and degree of suspicion of HCC. The sensitivity and the positive predictive value (PPV) were calculated for every reading session. The following statistical evaluations were used: k statistic and McNemar's test.
Results: Mean sensitivity and PPV in the detection of HCC were, respectively, 83.8% and 93.5% for EAP, 90.5% and 94.8% for LAP, and 94.1% and 95.1% for the double arterial phase. Sensitivity of the double arterial phase was statistically higher when compared with EAP alone but showed no statistically significant difference when compared with LAP. The k values ndicated moderate-to-excellent interobserver agreement in all reading sessions.
Conclusions: Sensitivity and PPV increase progressively when passing from EAP to LAP to double-arterial-phase images obtained with contrast material with a high iodine concentration. However, the difference in sensitivity between LAP and the double arterial phase was not statistically significant.