BACKGROUND: The various combination of multiphase enhancement multislice spiral CT(MSCT) makes the diagnosis of a small hepatocellular carcinoma(s HCC) on the background of liver cirrhosis possible. This study was to explore whether the combination of MSCT enhancement scan and alpha-fetoprotein(AFP) level could increase the diagnostic efficiency for s HCC.METHODS: This study included 35 s HCC patients and 52 cirrhotic patients without image evidence of HCC as a control group. The diagnoses were made by three radiologists employing a 5-point rating scale, with postoperative pathologic results as the gold standard. Receiver operating characteristic(ROC) curve analysis was performed to evaluate the diagnostic value of the three MSCT combination modes(arterial phase+portal-venous phase, arterial phase+delayed phase,arterial phase+portal-venous phase+delayed phase) and AFP levels for s HCC on the background of liver cirrhosis. RESULTS: The area under ROC curve(AUC), sensitivity,and specificity of the combination of arterial phase+portalvenous phase+delayed phase were 0.93, 93%, and 82%, respectively. The average AUC of the arterial phase+portalvenous phase+delayed phase combination was significantly greater than that of the arterial phase+portal-venous phase(AUC=0.84, P=0.01) and arterial phase+delayed phase(AUC=0.85, P=0.03). Arterial phase+portal-venous phase had a smaller AUC(0.84) than arterial phase+delayed phase(0.85), but the difference was insignificant(P=0.15). After combining MSCT enhancement scan with AFP, the AUC, sensitivity, and specificity were 0.95, 94%, and 83%, respectively, indicating a greatly increased diagnostic efficiency for s HCC.CONCLUSIONS: The combination of AFP and 3 phases MSCT enhancement scan could increase the diagnostic efficiency for s HCC on the background of liver cirrhosis. The application of ROC curve analysis has provided a new method and reference in HCC diagnosis. BACKGROUND: The various combination of multiphase enhancement multislice spiral CT (MSCT) makes the diagnosis of a small hepatocellular carcinoma (s HCC) on the background of liver cirrhosis possible. This study was to explore whether the combination of MSCT enhancement scan and alpha-fetoprotein (AFP) level could increase the diagnostic efficiency for HCC.METHODS: This study included 35 s HCC patients and 52 cirrhotic patients without image evidence of HCC as a control group. The diagnoses were made by three radiologists employing a 5-point rating scale , with postoperative pathologic results as the gold standard. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic value of the three MSCT combination modes (arterial phase + portal-venous phase, arterial phase + delayed phase, arterial phase + portal -venous phase + delayed phase) and AFP levels for HCC on the background of liver cirrhosis. RESULTS: The area under ROC curve (AUC), sensitivity, and specific ity of the combination of arterial phase + portalvenous phase + delayed phase were 0.93, 93%, and 82%, respectively. The average AUC of the arterial phase + portalvenous phase + delayed phase combination was significantly greater than that of the arterial phase + portal Arterial phase + portal-venous phase had a smaller AUC (0.84) than arterial phase + delayed phase (0.85, P = 0.01) and arterial phase + delayed phase ), but the difference was insignificant (P = 0.15). After combining MSCT enhancement scan with AFP, the AUC, sensitivity, and specificity were 0.95, 94%, and 83%, respectively, indicating a highly enhanced diagnostic efficiency for s HCC. CONCLUSIONS: The combination of AFP and 3 phases MSCT enhancement scan could increase the diagnostic efficiency for HCC on the background of liver cirrhosis. The application of ROC curve analysis has provided a new method and reference in HCC diagnosis.