磁共振在胰腺囊性肿瘤鉴别诊断中的价值

The value of magnetic resonance imaging in the differential diagnosis of pancreatic cystic neoplasms

目的：回顾性分析经手术病理证实的胰腺囊性肿瘤磁共振（MRI）形态学特征，以探讨MRI在囊性肿瘤鉴别诊断中的价值。方法：收集2010年4月-2015年4月间在本院行胰腺MRI检查，并经手术病理证实的胰腺囊性肿瘤38例，男25例，女13例．年龄32～64岁，其中浆液性囊腺瘤（SCN）16例，黏液性囊腺瘤（MCN）12例，胰腺实性假乳头状瘤6例，导管内乳头状黏液性肿瘤（IPMN）4例。结果：SCN多呈分叶状，囊小而多且有中心瘢痕，动态增强扫描后间隔明显强化呈高信号；MCN体积较大．平均直径76．0mm，壁结节及不规则增厚间隔明显强化，8例位于胰腺体、尾部。胰腺实性假乳头状瘤6例均为囊实性，囊性成分为主4例，实性成分为主2例，且周边均可见环形低信号的完整包膜。实性成分呈稍低T1稍高T2信号，囊性成分呈低T1高T2信号。动态增强扫描后，病变实性部分轻度强化，门脉期明显强化，延迟期与邻近胰腺实质比较呈高信号，囊性部分无强化呈低信号。IPMN主胰管型为3例，MRI示胰管扩张，直径最粗约5．0mm，胰管内可见乳头状稍长T1稍长T2信号结节影，增强后呈持续强化；分支胰管型1例，位于胰体部，呈多囊状长T1长T2信号，增强后显著强化呈高信号，MRCP示4例病变均与胰管相通，并可出现胰管远端或全程扩张，而SCN及MCN仅有胰管近端扩张。结论：高场MRI通过分辨胰腺囊性病变中囊灶、囊壁及间隔等不同形态学特征可提高诊断的准确率。

Objective： To analyze the morphological characteristics of pancreatic cystic neoplasms that have been patholog- ically proved to discuss the value of MRI in the differential diagnosis of pancreatic cystic neoplasms retrospectively. Methods： Totally 38 cases of pancreatic cystic neoplasms were included in the study from 2010 April to 2015 April, including male 25, female 13, age range 32N64 years. All the cases underwent MRI in our hospital and were pathologically proved. Among them serous cystic neoplasm（SCN） 16 cases, mucinous cystic neoplasms（MCN） 12 cases, solid pseudopapillary neoplasm（SPN） 6 cases and intraductal papillary mucinous neoplasm （IPMN） 4 cases. Results： SCN were usually lobular with many small cysts and central scars. The septum enhanced significantly to be high signal intensity after dynamic-contrast enhancement. MCN were usually large volume, mean diameter 76.0 mm. The mural nodule and irregulary thickened septum enhanced obviously. Eight cases of MCN were located in the body and tail of pancreas. Six cases of SPN were all cystic-solid, 4 cases of cystic domi- nated and 2 cases of solid dominated with intact capsule of ring low signal intensity. The solid portion showed slightly-low T1 and slightly-high T2 signals, while the cystic portion showed low T1and high T2 signals. After contrast dynamic enhancement, the solid portion enhanced gradually to be high signal intensity comparing with the adjacent pancreatic normal tissues. The cystic portion didn＇t enhance to be low signal. Three cases of IPMN were major pancreatic duct with the duct remarkedly di- lated, the maximum diameter was 5.0 mm. The papillary with slightly-low T1 and slightly-high T2 signal can be seen in the duct, enhanced gradually. Only 1 case was branch-type located in the tail of pancreas with many cysts of long TL and long T2 signals, enhanced significantly. In MRCP, 4 cases can be seen to communicate with the pancreatic duct, companyiug the distal or whole pancreatic duct dilation, while the duct only showed proximal dilation in SCN and MCN. Conclusion： High field magnetic resonance can significantly improve the diagnostic accuracy by showing the different morphological characteris- tics of cystic center, cystic capsule and septum in the pancreatic cystic neoplasms.