肝脏神经内分泌癌的CT及MRI特征

CT and MR imaging features of hepatic neuroendocrine carcinoma

目的探讨肝脏神经内分泌癌(HNEC)的CT及MRI特征,以期提高其诊断水平。方法回顾性分析经病理免疫组织化学证实的37例HNEC患者的影像资料,分析其表现特点。结果原发性HNEC常为单发,CT表现肿瘤平扫为低密度或混杂低密度占位,肿瘤合并出血时其内见斑片状稍高密度,增强扫描呈渐进性强化,肿瘤实性部分门脉及平衡期CT值略高于动脉期;磁共振DWI多呈均匀或厚壁样稍高信号,T2WI呈稍高信号,部分病变内见高信号囊变区,T1WI呈稍低信号,部分病变呈稍高信号,增强扫描呈中度均匀强化或边缘强化,部分病变内可见粗大供血动脉,门脉及延迟期呈等或稍低信号,部分病变可见完整或不完整假包膜,肿瘤周围门脉及肝静脉受压移位,但无癌栓形成。转移性HNEC常为多发、体积较大,CT平扫呈稍低或低密度,增强扫描动脉期病变多呈边缘轻中度强化或不均匀强化,门脉及平衡期相对肝实质呈等或稍低密度;磁共振检查DWI多呈环形高信号,T2WI呈稍高信号, T1WI呈稍低信号,大部分病变内见囊变坏死区,增强扫描动脉期不均匀强化或环形强化,门脉及延迟期多数可见偏心靶环征,部分门脉血管内可见癌栓。结论 HNEC可分为原发性和转移性,其影像学表现具有一定的特征性,结合临床资料及免疫组织化学有助于病变的诊断。

Objective To study the computed tomography (CT) and magnetic resonance (MR) imaging features of hepatic neuroendocrine carcinoma (NEC) in order to improve its diagnostic level. Methods The CT and MR imaging materials of 37 patients diagnosed as hepatic NEC by pathology and immunohistochemistry were retrospectively analyzed. Results Primary hepatic NECs were often single.Plain CT usually showed hypo-intense or mixed hypo-intense,and patchy high signals inside were observed when complicated with hemorrhage.In the enhanced scan,carcinomas showed gradually enhanced density.The CT values of solid lesions in portal phase and equilibrium phase were slightly higher than those in arterial phase.Usually primary hepatic NECs showed homogeneous or slightly higher thick-ring signals on MR diffusion-weighted imaging (DWI),slightly hyper-intense on T2-weighted imaging (T2WI) with some hyper-intense cystic zones inside,and slightly hypo-intense on T1-weighted imaging (T1WI) with some slightly hyper-intense lesions.The enhanced MR imaging of lesions showed moderate homogeneous enhancement or marginal enhancement with large arteries visible in some lesions,and iso-intensity or slightly hypo-intensity in portal and delayed phases.Some lesions showed complete or incomplete pseudo-capsule,and surrounding portal vein and hepatic vein were compressed without tumor thrombus.Liver metastatic NECs were often multiple and large.Plain CT scan showed hypo-intense or slightly hypo-intense.Compared with liver parenchyma,the enhanced scan of metastatic NECs usually showed heterogeneous enhancement or mild to moderate marginal enhancement in arterial phase,and iso-intense or slightly hypo-intense signals in portal and equilibrium phases.Meanwhile,liver metastatic NECs showed marginal hyperintensity on MR DWI,slightly hyper-intense on T2WI and slightly hypo-intense on T1WI,with cystic necrosis areas appearing in most of the lesions.The enhanced MR imaging showed heterogeneous or marginal enhancement in arterial phase and "eccentric target ring sign" in most of the portal and delayed phases.Tumor thrombi were visible in some portal veins. Conclusion Hepatic NECs can be divided into primary and metastatic tumors,whose imaging features have certain characteristics.Combined with clinical data and immunochemistry,CT and MR imaging are helpful for the diagnosis of lesions.