Abstract: Objective: To study the CT findings of hepatic lesions without obvious enhancement in arterial phase, and to analyze the characteristics of the hepatic lesions.Methods: The clinical materials of 118 cases of hepatic lesions without obvious enhancement in arterial phase scanned by enhanced CT were collected. The basic CT signs, characteristic CT signs and enhancement patterns were analyzed.Results: Among 118 cases, there were 40 hepatic metastases, 29 liver abscesses, 21 intrahepatic cholangiocelloma, 17 hepatocellular carcinoma, 6 inflammatory pseudotumor of liver and 5 hepatic lymphoma; 54 cases showed single lesion and 64 cases showed multiple lesions; 24 cases were sharp and 94 cases were indistinct; 41 cases located in right hepatic lobe, 26 cases located in left hepatic lobe, 50 cases located in left and right hepatic lobe, and 1 case located in hepatic caudate lobe. The diameters of lesions were 0.2-13.4 cm. 40 cases of hepatic metastases showed mild marginal enhancement, while the incidence rate of bull eye sign was 12.50% (5/40); 29 cases of liver abscess showed ring or honeycomb-like enhancement, while the incidence rates of double ring sign and gas bubbles were 13.79% (4/29) and 13.79% (4/29).Seventeen cases of intrahepatic cholangiocelloma showed slow progressive enhancement,while the incidence rates of intrahepatic bile duct dilatation, hepatic capsular depression and calcification were 57.14% (12/21), 23.81% (5/21) and 9.52%(2/21). Seventeen cases of hepatocellular carcinoma showed various enhancement patterns, while the incidence rates of liver contour change, hepatic artery enlargement and vessel invasion were 41.18% (7/17), 41.18% (7/17) and 35.29%(6/17). Four cases of inflammatory pseudotumor of liver showed septal and nodular enhancement; 5 cases of hepatic lymphoma showed internal minimal homogeneous enhancement, while the incidence rate of ‘vascular floating’ sign was 40.00% (2/5).Conclusion: Spiral CT examination of the hepatic lesions without obvious enhancement in arterial phase should be combined with CT signs and enhancement patterns for synthetic judgment, which is helpful to provide an important basis for the qualitative and differential diagnosis of liver lesions.

Key words: liver, lesions, computed tomography, dynamtic contrast enhancement, differential diagnosis