脑泡状棘球蚴病CT和MRI表现及诊断

目的 总结脑泡状棘球蚴病的影像特征,探讨CT和MRI的诊断价值.方法 回顾性分析经手术病理和临床随访证实的17例脑泡状棘球蚴病患者的CT和MRI表现,观察病灶的数目、部位、形态、边界、大小、密度及灶周水肿.结果 单发病灶6例,多发病灶11例.病灶数目共51个,位于额顶叶占66.6%(34/51),位脑皮层区占73.1%(37/51);病灶0.5～5.0 cm直径大小,CT平扫呈结节状或团块状高或稍高密度占86.3%(44/51),边缘粗糙,增强后大多呈环状强化,小病灶可呈结节样强化;MRI的T1WI平扫病灶大多呈稍高信号,T2WI及液体衰减反转恢复序列(FLAIR)呈"黑洞"或"煤饼"样均匀或不均匀低信号,增强后病灶强化表现与CT相仿,但强化的灰阶对比度高于CT;病灶占位效应明显,灶周均有水肿表现,常呈现"烘托效应";肝脑肺"三联征"占70.6%(12/17);CT综合MRI并以灰阶高低统一描述,则有"两等和(或)两高两低"征象.结论 脑泡状棘球蚴病CT和MRI表现具有特征性,CT和MRI联合应用和综合评价对该病具很高的诊断价值,流行病学及相关免疫学检查仍不可忽视.

CT and MRI features and diagnosis of alveolar echinococcosis of the brain

Objective To summarize the CT and MRI imaging characteristics of alveolar echinococcosis of the brain and evaluate these techniques in its diagnosis. Methods A retrospective analysis of spiral CT imaging findings was performed in 17 cases of alveolar echinococcosis of the brain, in which the diagnosis was confirmed by operative pathologic evaluation and clinical follow up. In each case,the number, site, shape, margin, size, density and surrounding edema were evaluated for each lesion.Results CT demonstrated a single lesion in 6 cases, and multiple lesions in 11 cases. There were 66. 6%(34/51 ) of the lesions located in the frontal and parietal lobes, and 73. 1% (37/51 ) located in the cerebral cortex area. The size of lesions ranged from 0. 5 to 5.0 cm, and 86. 3% (44/51) showed nodular or mass lesion with high density or slight high density and indistinct "fuzzy" edges. Larger lesions showed ring shape with thick mural enhancement after contrast enhancement while smaller ones showed nodular shape. The majority of lesions showed slightly high signal intensity on T1 WI. T2 WI and FLAIR showed homogeneous or homogeneous low signal intensity with the shape of a"black hole" or "briquette". MRI and CT image findings were similar for these lesions after contrast enhancement, but MRI showed better contrast than CT after enhancement. The space occupying effect of these lesions with surrounding edema was remarkable, and "set off by contrast effect" features were observed on CT. Simultaneous demonstration of echinococcal lesions in the liver, brain and lung ( the "triple sign" ) was found in 70. 6% ( 12/17 ) of cases. When CT and MR images were combined, the gray scale of contrast gradient for echinococcal brain lesions showed" two equal grade and/or two higher two lower" features. Conclusions CT and MRI findings in cases of alveolar echinococcosis of the brain are relatively characteristic. Comprehensive evaluation with both CT and MRI scans can be a valuable tool for the diagnosis. However, epidemiologic assessment and immunologic examination cannot be ignored.