无胆管扩张的肝内胆管细胞癌的MRI特征及其病理基础

MRI characteristics and pathological correlation regarding the intrahepatic cholangiocarcinoma without cholangiectasis

目的：探讨无胆管扩张的肝内胆管细胞癌的MRI特征及其病理基础。方法回顾性分析经手术病理证实为周围型肝内胆管细胞癌，且病灶为直径≤3 cm的肝内孤立结节，术前行MRI检查的12例患者资料。患者均行腹部MRI平扫及动态增强扫描。观察患者的MRI表现，并与病理结果进行对照。结果 MRI平扫T1WI为低信号8例、混杂性低信号4例；T2WI为高信号8例、混杂性高信号4例。1例病灶动脉期明显强化，门静脉期及延迟期呈等信号；病理诊断为低分化胆管腺癌。10例动脉期呈不均匀强化或环形强化，其中3例动脉期病灶周边呈薄环形强化，门静脉期呈低信号，延迟期呈等信号。周边薄环强化组织对应的病理改变为成活肿瘤细胞，中心延迟强化组织为大量纤维结缔组织。4例动脉期病灶周边呈厚环形强化，3例门静脉期及延迟期呈低信号，1例延迟强化。厚环形强化对应的病理改变为成活肿瘤细胞，中心延迟强化组织为大量纤维结缔组织，少量坏死组织。3例动脉期呈岛状强化或不均匀强化，对应的病理改变为肿瘤组织及少量纤维结缔组织、部分坏死组织。1例3期扫描肿瘤均无强化，对应的病理改变为肿瘤明显囊性扩张、出血、坏死，肿瘤与正常肝组织间见成活肿瘤细胞。结论无胆管扩张的肝内胆管细胞癌MRI表现具有一定特征性，不同MRI表现具有其病理基础。

Objective To studying the MR findings and pathology of peripheral small intrahepatic cholangiocarcinoma and improving the understanding of peripheral small cholangiocarcinoma with no-bile duct dilatation. Methods A retrospective analysis of 12 patients with intrahepatic peripheral cholangiocarcinoma which were confirmed by surgery and pathology, all patients were examined by abdominal MRI without and with contrast. Correlation was made with gross pathology and surgical pathological specimen. Results On T1WI, there were 4 cases of complex low signal intensity and 8 cases of low signal intensity. On T2WI, there were 8 cases of high signal intensity and 4 cases of complex high signal intensity. Enhanced MRI showed： marked nidus enhancement on arterial phase in 1 case, and the pathological diagnosis was poorly differentiated adenocarcinoma. Inhomogeneous enhancement or annular enhancement were seen in 10 cases on arterial phase, 3 of these cases showed thin annular enhancement on arterial phase, low signalintensity on portal venous phase and isointensity on delayed phase. One case showed delayed enhancement. Thick circular enhancement correlated with pathological changes of survival of tumor cells, center areas correlated with fibrous connective tissue, and a small amount of necrotic tissue. Island-like enhancement or inhomogeneous enhancement were seen in 3 cases. Corresponding pathological changes consisted of tumor tissue and a small amount of fibrous connective tissue, as well as somenecrotic tissue. In 1 case, no enhancement was seen on all three phases and pathological changes showed cystic changes, hemorrhage, necrosis, with survival tumor cells seen between cyst and normal liver tissue.＆nbsp;Conclusions MRI scanning of peripheral small cholangiocarcinoma lacked characteristic features, but dynamic contrast-enhanced MR had certain specific findings. Due to different pathology, the fibrous tissue, necrotic tissue and survival tumor tissue components were exhibited different imaging findings.