胰腺神经内分泌肿瘤的影像学表现与病理对照分析 Pancreatic Neuroendocrine Tumors: Correlation between the Imaging Findings and Pathology

目的：探讨胰腺神经内分泌肿瘤的影像学特征，以提高对其诊断水平。方法：回顾性分析24例经病理证实的胰腺神经内分泌肿瘤患者的影像资料,并与病理结果进行对照分析。结果：8例功能性胰腺神经内分泌肿瘤平均大小为2.1 cm × 2.6 cm，平扫7例呈均匀的等或稍低密度，1例呈稍长T1、稍长T2信号，1例胰头肿瘤侵及十二指肠；16例非功能性胰腺神经内分泌肿瘤平均大小为2.5 cm × 4.3 cm，其中9例为实性，5例为囊实性，2例为囊性，实性部分呈等或稍低密度，MRI上呈稍长T1、稍长T2信号，囊性部分呈近似水样密度或信号，6例与十二指肠分界不清，2例出现脾静脉局部变细，1例肿瘤与脾脏分界不清，5例出现腹膜后或胰周淋巴结转移。增强扫描动脉期17例表现为明显强化，7例表现为轻-中度强化，9例可见包膜环形强化；与动脉期强化程度相比，门静脉期及延迟期19例强化程度下降，另有2例呈肝血管瘤样的填充式强化，3例呈渐进性强化。与手术病理诊断对照，术前影像诊断符合率为67% (16/24)。结论：功能性胰腺神经内分泌肿瘤多表现为较小的实性结节，非功能性者多表现为较大的不均质肿块，增强扫描呈明显强化、包膜环形强化为其特征，轻-中度强化及明显囊变者相对少见。 Objective: To investigate imaging features of pancreatic neuroendocrine tumors (PanNETs), so as to improve its clinical diagnosis. Materials and Methods: A retrospective analysis of the imaging data of 24 patients with pathologically confirmed PanNETs is conducted and the results were compared with the pathology. Results: There were 8 functional PanNETs with an average size of 2.1 cm × 2.6 cm, which showed homogeneous density or signal, 1 case of which had invasion of duodenum. There were 16 non-functional PanNETs with an average size of 2.5 cm × 4.3 cm, nine of which were solid lesions, seven of which were cystic lesions. Solid part of the PanNETs showed equal or slightly low density, and slightly longer T1, T2 signal in the MRI. Cystic part of the PanNETs showed water-like density or signal. 6 cases had unclear boundaries with duodenum, 1 case had unclear boundaries with spleen, and two cases appeared to thinner splenic vein. 5 cases had lymph node metastasis in retroperitoneal or peripancreatic. Contrast-enhanced examinations showed that 17 lesions had marked enhancement, 7 lesions had mild-moderate enhancement, and 9 lesions had capsule marked ring-like enhancement. 19 lesions had decreased enhancement in the portal venous phase and delay phase, 3 lesions had progressive enhancement, and 2 lesions had filled enhancement. The preoperative accuracy of diagnosis compared with pathology was  67% (16/24). Conclusion: Functional PanNETs could be manifested as small solid nodules, and non-functional ones could be manifested as large heterogeneous lump. PanNETs were characterized by marked enhancement with capsule marked ring-like enhancement during contrast scanning, mild-moderate enhancement and obviously cystic changes were relatively rare.