不典型肝脓肿的影像学表现及鉴别诊断

摘要

Atypical hepatic abscess pathological process is complex,the signs of which overlap with other liver disease, resulting in the difficult diagnosis and differential diagnosis of atypical cases. In the period of inflammation,lesions do not present necrosis and liquefaction,and the performance is solid sign.In the early abscess formation stage,it begins to form the multiple scattered small abscess cavities which then gather and merge,and dynamic enhanced scan shows "honey sign""cluster sign" or "petal sign".In the abscess formation stage,complete necrosis and liquefaction of the lesion is obser ved,and abscess wall is mature,and enhanced scan shows typical"ring target sign";some lesions show"small bubbles"or"gas level".In the fibrous granulomatous stage,the lesions show small "petal sign",single or double-ring sign.Transient hepatic abnormal enhancement(THAE sign)is an important sign of atypical hepatic abscess,which can be expressed as"continuous strengthening sign" and "reduction sign"in enhanced scan venous phase and delayed phase.Biliary system infection and/or intestinal gas retrograded into the biliary tract,the expanded and gas accumulation of intrahepatic bile duct of the lesion edge,are also important manifestations of intrahepatic bile abscess.Therefore,atypical liver abscess imaging signs are complex in the different stages of the pathology,which need to be differentiated from hepatocellular carcinoma,cholangio-carcinoma,liver metastases,inflammatory pseudotumor and other liver diseases.In the actual diagnosis,close combination with clinical and related laboratory tests is particularly important for the comprehensive analysis and identification.%不典型肝脓肿病理过程复杂,影像上与其他肝脏疾病征象间存在重叠,致使不典型病例的诊断及鉴别诊断困难.在化脓性炎症期,病灶未发生液化坏死,表现为实性征象.脓肿形成初期,病灶开始液化坏死形成多个散在的微小脓腔,随后聚集、融合,增强扫描呈"蜂窝征""簇形征"或"花瓣征".脓肿形成期,病灶坏死液化彻底,脓肿壁成熟,增强扫描呈典型"环靶征",部分病灶内可见"小气泡"或"气液平".纤维肉芽肿期病灶呈较小的"花瓣征"、单环或双环征.增强扫描动脉期,肝实质一过性异常强化现象(THAE征)出现率较高,是不典型肝脓肿的重要征象;静脉期和延迟期,可表现为"持续强化征"和"病灶缩小征".胆管系统感染和(或)肠道内气体逆行进入胆管内,脓肿边缘肝内胆管扩张、积气,亦是肝内胆管脓肿的重要征象.因此,不典型肝脓肿随着病程进展其影像学征象复杂,在不同病理阶段需与肝细胞癌、胆管细胞癌、肝转移癌和炎性假瘤等其他肝脏疾病相鉴别.在实际诊断中,密切结合临床症状以及相关实验室检查对其进行综合分析、鉴别诊断显得尤为重要.