获得性弓形体脑病的影像学表现

Imaging Manifestations of Acquired Toxoplasmosis Encephalopathy

目的:探讨获得性弓形体脑病的影像学表现,以提高对此病的认识。方法:回顾分析17例临床诊断为获得性弓形体脑病患者的头颅MRI及CT资料,探讨弓形体脑病的影像学表现。结果:17例患者的MRI均为多发性病灶,总病灶数为215个,平均(12.64±10.25)个,其中16例皮髓质交界区有病灶,平均(10.47±8.95)个;病灶也可发生在基底节区,较少发生在小脑、脑干,脑膜可受累。病灶多呈结节状、团块状、斑片状,其中11例可见病灶周围有水肿带,可有占位效应。平扫T1加权像(T1 weighted image,T1 WI)呈边界不清的等低信号影,T2加权像(T2 weighted image,T2 WI)、液体衰减反转恢复(fluid atten-uated inversion recovery,FLAIR)、扩散加权成像(diffusion weighted imaging,DWI)呈高信号为主。15例行MR增强扫描,均有不同程度的环状、结节状及斑片状明显强化,其中7例脑膜呈结节状或线状增厚强化;10例经抗弓形虫治疗后复查MR显示病灶有明显吸收好转。磁共振波谱(magnetic resonance spectroscopy,MRS)可观察病灶的发展及转归的代谢信息变化。CT平扫主要呈等密度结节灶及片状低密度区,增强后呈不同程度的结节状、片状或环状强化。结论:结合临床资料及影像学检查可以诊断获得性弓形体脑病,MRI可作为首选影像学检查方法。

Objective：To investigate the imaging manifestations o{ acquired toxoplasmosis encephalopathy. Methods： Magnetic resonance imaging（MRI） and computed tomography（CT） image findings of 17 patients with acquired toxoplasmosis encephalopathy proved by clinical data were analyzed retrospectively. Results： A total of 215 lesions of 17 patients were indicated on MRI, with an average of （12.64 ± 10.25）. In 16 patients, lesions were found in corticomedullary iunction, with an average of （10.47 ± 8.95）. Lesions were also found in the basal ganglia,less likely in cerebellum and brainstem. Meninges could also be affected. Lesions mainly presented as nodules,masses and patches. Edema belts around the lesions were observed in 11 patients, which might have mass effect. Lesions showed iso-intensity or hypo-intensity with unsharp margins on Tl-weighted images （T1WI） and primary hyper-intensity on T2-weighted images （T2Wl）, fluid attenuated inversion recovery（FLAIR） and diffusion weighted imaging（DW1）. MR enhancement scanning was applied in 15 patients, with varying degree of annular, nodular and patchy enhancements. Seven patients appeared meningeal nodular or linear thickening enhancement. After anti-toxoplasma treat ment, obvious absorptions were found in lesions of 10 patients through the follow-up by MR scanning. Magnetic resonance spectroscopy（MRS） could be used to observe metabolism variation and development of lesions. Lesions on CT plain scan mainly presented as iso density nodules and patchy low density zone, while lesions displayed nodular, flake or ring-like enhancement after enhancement. Conclusions： The combination of clinical data and imaging examination can help to diagnose acquired toxoplasmosis encephalopathy,and MRI should be the first choice of imaging examination, which is an effective in the diagnosis and therapeutic evaluation of lesions.