脑曼氏裂头蚴的特征性MRI表现

Feature Findings of Cerebral Sparganosis on MRI

目的:研究脑曼氏裂头蚴的常规MRI特征性表现。材料和方法:收集经手术病理确诊的6例脑内曼氏裂头蚴,回顾性分析其常规MRI表现,包括病灶分布、数目、形态、大小、信号及强化情况。结果:脑曼氏裂头蚴的常规MRI表现为:6例均单发病灶,病灶位置表浅,3例位于顶叶,1例位于额叶,1例位于颞叶,1例位于脑干后部;5例病灶形态不规则,3cm左右大小,T1WI呈不均匀低或略低信号,T2WI呈不均匀高信号,中央略高,周围高信号;5例强化后表现为多个小环状强化,并不规则相套,呈“绳结状”;1例表现为环形边缘强化,壁中等厚度,内外壁较光整,强化病灶周围均可见轻微水肿未见以往文献中描述的白质退变或出血。MRI3例诊断为裂头蚴,3例诊断为寄生虫感染。5例MRI表现“绳节状”强化病例手术中可见活虫,1例MRI表现环状强化病灶者,环内囊腔中仅见少量虫体碎片。结论:“绳结状”强化是脑内曼氏裂头蚴的典型MRI特征,与胶质瘤及其他感染性病灶有一定的鉴别诊断价值。但病灶呈单发囊腔表现时,易与脑脓肿及其他寄生虫感染混淆。

Purpose： To explore the character of cerebral sparganosis on MRI. Materials and Methods： MR imaging of six patients with cerebral sparganosis were reviewed retrospectively. To analysis the distribution, the shape and the intensity of pre- and post- enhancement of the lesions.Results： All cases shown a single lesion. The location of lesions were superficial, three were in parietal lobe, one in frontal lobe, one in temporal lobe and one in posterior part of brain stem. Five lesions were irregular shape and about 3cm in size with moderate hypo- intensity on T1WI and hyper - intensity on T2 WI. A presenting feature of the parasitic granuloma ＂string - knot shape＂ enhancement was demonstrated in five cases. One case showed a cyst - like lesion with peripheral enhancement. There were slight hyper - intensity surrounding the nodular lesions which corresponding to edema. Diagnosis of sparganosis was made on base of characteristic enhancement in MRI for three cases, and three were diagnosed as parasitic infections disease. During surgery, live larvas of sparganum were successfully removed in five cases with ＂string - knot shape＂ enhancement lesions on MRI. In case with cyst - like lesion, only fragment of worm body were obtained. Conclusion： ＂String- knot shape＂ enhancement was a MRI characteristic finding, which was valuable in diagnosis of cerebral sparganosis.