摘要目的 探讨胰腺神经内分泌肿瘤(pNENs)的CT和MRI表现特征.方法 采用回顾性描述性研究方法.收集2012年5月至2016年2月华中科技大学同济医学院附属同济医院收治33例pNENs患者的临床病理资料.患者行CT和MRI平扫和增强扫描检查.观察指标:(1)pNENs总体影像学表现及病理学结果.(2)功能性pNENs的影像学表现.(3)无功能性pNENs的影像学表现.主要分析肿瘤直径、部位、边界、密度、囊变、强化、信号、钙化、是否合并胰胆管扩张、有无周围组织侵犯、淋巴结及远处器官转移等信息.结果 (1)pNENs总体影像学表现及病理学结果:33例pNENs患者中,24例行CT检查,3例行MRI检查,6例同时行CT和MRI检查.33例患者肿瘤均为单发,肿瘤直径为0.6～16.0 cm.肿瘤部位:胰头部10例、胰腺钩突部1例、胰体部13例、胰尾部9例.33例患者均经病理学检查诊断为pNENs,20例为功能性pNENs(均为胰岛素瘤),13例为无功能性pNENs.33例pNENs患者中,G1级24例,G2级7例,G3级2例.术前CT、MRI检查与病理学检查诊断符合率为90.9％(30/33),3例误诊患者术前诊断为胰腺癌1例、胰周肿大淋巴结1例、十二指肠间质瘤1例.(2)功能性pNENs的影像学表现:20例功能性pNENs患者,肿瘤直径为0.6 ～3.0 cm,平均肿瘤直径为1.5 cm.肿瘤部位:胰头部4例,胰体部10例,胰尾部6例.20例功能性pNENs患者中,19例肿瘤边界清楚,1例肿瘤边界欠清晰.20例功能性pNENs患者中,18例肿瘤密度均匀,2例肿瘤密度不均伴囊变,肿瘤均不伴有钙化.20例行动态增强扫描患者:19例肿瘤动脉期强化明显,门静脉期及延迟期强化程度稍高或等于正常胰腺组织,1例肿瘤动脉期呈弱强化、门静脉期及延迟期强化程度等于或稍低于正常胰腺组织.3例患者行MRI扫描检查患者:肿瘤均表现为脂肪抑制T1加权成像呈低信号,T2加权成像呈高信号,DWI(b=1 000 s/m2)高信号,肿瘤显示清晰.20例患者中,1例伴有肿瘤远端胰腺组织萎缩、胰管扩张、多发潴留囊肿及肝总动脉旁淋巴结肿大.(3)无功能性pNENs的影像学表现:13例无功能性pNENs患者,肿瘤直径为1.5～16.0 cm,平均肿瘤直径为5.0 cm.肿瘤部位:胰头部6例,胰腺钩突部1例,胰体部3例,胰尾部3例.13例无功能性pNENs患者中,11例肿瘤边界清晰,2例边界不清晰.13例无功能性pNENs患者中,3例肿瘤密度较均匀,10例密度不均,伴有囊变.13例无功能性pNENs患者中,2例肿瘤伴有钙化.13例行动态增强扫描患者:其中12例肿瘤动脉期强化明显,门静脉期及延迟期持续性强化,囊变区强化不明显,部分肿瘤可见明显增粗的供血动脉及引流静脉;1例肿瘤强化较弱,三期强化程度均稍低于正常胰腺组织,边界不清晰.6例患者行MRI扫描检查,4例患者肿瘤脂肪抑制T1加权成像呈低信号,T2加权成像呈稍高或混杂信号,DWI(b=1 000 s/m2)呈高信号;2例患者肿瘤脂肪抑制T1加权成像呈低信号,T2加权成像呈低信号,DWI(b=800 s/m2)呈稍高信号.13例无功能性pNENs患者中,4例出现胆管及胰管扩张.7例无功能性pNENs患者出现局部组织侵犯或远处转移(肝脏转移4例、胰腺周围淋巴结转移1例、肝脏和胰腺周围淋巴结同时转移1例,肝脏转移及脾动静脉侵犯1例),其中G1级1例,G2级4例,G3级2例.5例肿瘤直径＞5.0 cm患者中,4例出现肝脏或淋巴结转移.结论 pNENs的CT和MRI检查表现具有一定特征性.功能性pNENs以良性多见,边界清楚,直径较小,以实性为主,增强时动脉期呈显著强化.无功能性pNENs肿瘤体积较大,瘤内常见囊变坏死,肿瘤强化方式呈多样性.

abstractsObjective To investigate the features of computed tomography (CT) and magnetic resonance imaging (MRI) on pancreatic neuroendocrine tumors (pNENs).Methods The retrospective and descriptive study was adopted.The clinicopathological data of 33 patients with pNENs who were admitted to the Tongji Hospital of Tongji Medical School of Huazhong University of Science and Technology between May 2012 and February 2016 were collected.All the patients underwent plain and enhanced scans of CT and MRI.Observation indicators:(1) overall imaging findings and pathological results of pNENs,(2) imaging findings of functional pNENs,(3) imaging findings of non-functional pNENs.Main analysis indicators included tumor diameter,location,boundary,density,cystic degeneration,enhancement,signal,calcification,with or without pancreaticobiliary duct dilation,with or without surrounding tissues invasion,lymph node and distant organ metastases.Results (1) Overall imaging findings and pathological results of pNENs:of 33 patinets with pNENs,24 underwent CT examination,3 underwent MRI examination and 6 underwent CT and MRI examinations.Tumors of 33 patients were solitary with a diameter of 0.6-16.0 cm.Ten,1,13 and 9 tumors were respectively located at the head of pancreas,uncinate process of pancreas,body of pancreas and tail of pancreas.Thirty-three patients were diagnosed as pNENs by pathological examination,including 20 with functional pNENs (insulinoma) and 13 with non-functional pNENs,and G1,G2 and G3 were respectively detected in 24,7 and 2 patients.The coincidence rate between preoperative CT or MRI examination and pathological examination was 90.9％ (30/33).One,1 and 1 patients were misdiagnosed as pancreatic cancer,enlargement of peripancreatic lymph nodes and duodenal gastrointestinal stromal tumor,respectively.(2) Imaging findings of functional pNENs:tumor diameter of 20 patients with functional pNENs was 0.6-3.0 cm with an average diameter of 1.5 cm.Fòur,10 and 6 tumors were respectively located at the head of pancreas,body of pancreas and tail of pancreas.Of 20 patients with functional pNENs,tumors of 19 patients showed clear boundary and 1 showed unclear boundary,and tumors of 18 patients had uniform density and 2 had uneven density with cystic degeneration,without the occurrence of calcification.Of 20 patients undergoing dynamic enhanced scans,tumors of 19 patients demonstrated obvious enhancement in arterial phase and slightly obvious enhancement or were equal to normal pancreatic tissues in portal vein phase and lag phase,and tumor of 1 patient demonstrated slight enhancement in arterial phase and was equal to or less than normal pancreatic tissues in portal vein phase and lag phase.Tumors in 3 patients undergoing MRI scans were manifested as hypointensity on T1-weighted imaging (T1WI),hyperintensity on T2WI and hyperintensity on DWI (b =1 000 s/m2),with clear imaging.Of 20 patients,1 was accompanied with atrophy of pancreatic tissues at distal tumor,pancreatic duct dilatation,multiple retention cyst and enlargement of lymph nodes around the hepatic artery.(3) Imaging findings of non-functional pNENs:tumor diameter of 13 patients with non-functional pNENs was 1.5-16.0 cm with an average diameter of 5.0 cm.Six,1,3 and 3 tumors were respectively located at the head of pancreas,uncinate process of pancreas,body of pancreas and tail of pancreas.Of 13 patients with non-functional pNENs,tumors of 11 patients showed clear boundary and 2 showed unclear boundary,tumors of 3 patients had uniform density and 10 had uneven density with cystic degeneration,and tumors of 2 patients had calcification.Of 13 patients undergoing dynamic enhanced scans,tumors of 12 patients demonstrated obvious enhancement in arterial phase,continuous enhancement in portal vein phase and lag phase and less obvious enhancement at cystic degeneration area,with marked enlargement of supplying arteries and draining veins in partial tumors.Tumor of 1 patient demonstrated slight enhancement,and its enhancement was slightly less than normal pancreatic tissues in arterial phase,portal vein phase and lag phase,with unclear boundary.Results of MRI scans in 6 patients showed that tumors of 4 patients were manifested as hypointensity on T1WI,slight hyperintensity or mixed signal on T2WI and hyperintensity on DWI (b =1 000 s/m2),and tumors of 2 patients were manifested as hypointensity on T1WI,hypointensity on T2WI and hyperintensity on DWI (b =800 s/m2).Of 13 patients with non-functional pNENs,4 had pancreaticobiliary duct dilation and 7 had local tissues invasion or distant organ metastasis (4 with liver metastasis,1 with peripanereatic lymph node metastasis,1 with liver and peripancreatic lymph node metastases and 1 with liver metastasis combined with splenic venous and arterial invasion),including 1 in G1,4 in G2 and 2 in G3.Of 5 patients with tumor diameter ＞ 5.0 cm,4 were complicated with liver or lymph node metastases.Conclusions CT and MRI features of pNENs have a certain characteristics.For functional pNENs,benign and solid tumor is common,with clear boundary and smaller diameter.For non-functional pNENs,tumor size is bigger and cystic necrosis occurs within the tumor,with various enhancements.