外周神经源性肿瘤的MRI表现

MRI appearances of peripheral neurogenic tumors

目的:探讨外周神经源性肿瘤的MRI征象,提高对该病的诊断水平。方法:回顾性分析23例经手术病理证实的外周神经源性肿瘤的MRI表现,其中神经鞘瘤14例,神经纤维瘤9例。结果:23例肿瘤位于四肢及腰背部肌间隙或肌肉内、颈动脉鞘周围或骶前间隙。23例肿瘤中不均匀混杂信号17例,肿瘤呈等T1长T2信号间夹杂弥漫多发梭状、斑点片状长T1短T2影;靶征2例,表现为边缘呈环形呈长T2信号,中央呈短T2信号,增强扫描中央强化;囊性或囊实性4例,表现为肿瘤内见多发长T1长T2囊变区,囊壁及分隔呈短T2信号,增强扫描可见囊壁及分隔强化。3例肿瘤周围软组织轻度水肿。2例可见肿瘤邻近肌肉萎缩征象。结论:外周神经源性肿瘤发生部位、形态、边界及信号特点、瘤周是否水肿等MRI表现具有一定特点,有利于术前做出准确诊断。

Objective：To investigate the MRI fearures of peripheral neurogenic tumor,in order to improve the diagno- sis accuracy. Methods： MRI findings of 23 peripheral neurogenic tumors, including schwannoma （n= 14） and neurofibroma （n=9） were retrospectively analyzed. All eases were proved by surgery and pathology. Results： All of the 28 tumors located within intermuscular space or muscle of extremities or trunk, carotid sheath or presacral space. Of the 23 tumors, there were mixed heterogeneous signal intensities （n= 17）, hypointensity on T1 WI and hyperintensity on T2 WI, mixed with multiple fusiform, patchy low signal intensity on T1 WI and T2 WI;there was target sign in two cases, showing as peripheral hyperin- tense rim and central low intensity on T2 WI, with central enhancement after contrast administration; cystic or cystic-solid appearance was revealed in four cases,showing multiple hypointense cystic areas on T1WI and hyperintense on T2 WI with hypointense cystic wall and septae which were enhanced after contrast. Slight peri-tumoral edema could be assessed in 3 ca- ses. Muscle atrophy adjacent to the tumor could be revealed in 2 cases. Conclusion：Certain MRI characteristics including lo- cation, shape,margin, signal intensities, peri-tumoral edema are very conducive to establish the pre-surgical diagnosis of neu- rogenic tumor.