目的研究小肝细胞癌的少见 CT强化表现及原因，以提高小肝细胞癌 的诊断准确性。方法 回顾性分析经手 术及病理证实的20例小肝细胞癌的25个 癌灶的少见CT强化表现，与典型肝细胞 癌强化图像对比，总结其影像学特征。 结果 20例患者共发现25个癌灶。除2例 患者平扫呈等密度影，其它病灶平扫均 呈低密度灶。增强后５例动脉期呈高密 度影，门脉期、平衡期等密度影；２例 动脉期、门脉期呈高密度影，平衡期呈 低密度影；３例动脉期、门脉期呈高密 度影，平衡期仍呈高密度影，边缘见环 形廓清现象；２例增强后动脉期呈等密 度影，门脉期、平衡期呈低密度影，边 界较清楚；２例增强后三期未见明显强 化，即“三低”病灶；３例增强后动脉 期呈轻度强化，强化程度低于肝实质， 边界较清楚并呈轻度不规整，门脉期仍 呈低密度影，病灶内散在更低密度灶， 较前明显，平衡期呈低密度影；３个患 者呈多灶性起源，其中２例患者各３个 病灶，各病灶呈现同步强化；１例患者 ２个病灶，呈不同步强化。结论 小肝细 胞癌的少见强化表现多种多样，但三期 动态CT扫描技术是小肝细胞癌诊断的可 靠影像学诊断方法。

Objective To investigate the rare CT enhancement performances of small hepatocellular carcinoma and the reasons. To improve the diagnostic accuracy of small hepatocellular carcinoma(SHCC). Methods The rare CT enhancement performances of 20 patients with SHCC(25 lesions) confirmed by operation and pathology were retrospectively analyzed and were compared with the enhancement performances of typical SHCC. The imaging characteristics were summarized. Results 25 lesions were found in 20 cases. Except 2 lesions showed isodense focuses, the other 23 lesions showed high density focuses in plain CT scan. On contrast- enhanced CT imges, 5 cases showed high density focuses in arterial phase and isodense in portal vein and equilibrium phase. 2 cases showed high density focuses in arterial and portal venous phase and low density focuses in equilibrium phase. 3 cases showed high density focuses in arterial and portal venous phase and edge annular clearance in equilibrium phase. 2 cases showed isodense focuses in arterial phase and low density focuses in portal venous and equilibrium phase.2 cases showed no enhancement in three phase("three low density" lesions). 3 cases showed mild enhancement in arterial phase(less than the liver) with the clear and slight irregular boundary, and it showed low density focuses in the portal venous phase with scattered lower density focuses and low density focuses in equilibrium period. 3 cases were multiple focal original, of which 2 cases had 3 lesions respectively and the lesions showed synchronous enhancement, and 2 lesions in 1 case showed asynchronous enhancement. Conclusion There are various rare CT enhancement performances of small hepatocellular carcinoma. Three phase dynamic CT scan is a reliable diagnostic method in the diagnosis of small hepatic cell cancer.