Abstract 104: Valuation of Small Hepatocellular Carcinoma with Multidetector-Row Helical CT of the Liver: The Value of Dual Phase Arterial Scanning
AUTHORS:
M. Kadota, MD, Y. Yamashita, MD, Y. Nakayama, MD, K. Mitsuzaki, MD, A. Arakawa, MD, M. Takahashi, MD.
ABSTRACT:
PURPOSE: The purpose of this study was to evaluate the value of dual-phase arterial imaging of the liver by means of multidetector-row helical CT in diagnosing small hepatocellular carcinomas in patients with chronic liver disease.
METHOD AND MATERIALS: Ninety-seven consecutive patients with chronic liver disease received multidetector-row helical CT of the liver who had liver cirrhosis and were referred for known or suspected small hepatomas (3 cm or smaller in diameter). Proof of individual neoplasms was based on biopsy results, surgical findings, or findings of other imaging studies. Sixty percent nonionic contrast material, infused at 3 ml/sec, was followed by sequential early-arterial phase, delayed-arterial phase, and equilibrium phase helical scans of the liver. The scan delay of early-arterial phase and delayed-arterial phase helical scan were respectively 25 sec and 35 sec, and these two phases were obtained during single breath-hold. The scan delay for equilibrium phase helical scan was 180 sec. The slice thickness for all phases was 5-mm collimation and pitch was 6:1 (high speed mode) for double arterial phase and 3:1 (high quality mode) for equilibrium phase. Lesion conspicuity during each phase of imaging was evaluated prospectively by three radiologists. After independent reviews, consensus was obtained by consensus. Results were statistically analyzed using the receiver operating characteristic (ROC) method, and sensitivities for lesion detection were also calculated.
RESULTS: In 109 hepatomas, 7 tumors were more conspicuous in the early-arterial phase and 35 tumors in the delayed-arterial phase, while four tumors were more conspicuous in the equilibrium phase. The mean area under ROC curves were 0.87 for combination of double arterial phase, 0.76 for early-arterial phase, 0.81 for delayed-arterial phase and 0.72 for equilibrium phase. The sensitivity of combination of double arterial phases (92.3%) was significantly higher than that of only early-arterial phase (78.2%) or delayed-arterial phase (85.3%) (p< .01).
CONCLUSIONS: Dual-phase arterial imaging by means of multidetector-row helical CT of the liver after injection of contrast material significantly improves detection of small hepatocellular carcinomas when performed in addition to equilibrium phase scanning.
