艾滋病合并弓形虫脑炎的核磁共振成像表现特征

目的探讨艾滋病合并弓形虫脑炎的核磁共振成像(MRI)的表现特征,提高对该病的认识,以减少漏诊及误诊。方法对23例艾滋病合并弓形虫脑炎的MRI资料进行系统性回顾分析。结果 23例艾滋病合并弓形虫脑炎患者共有118个病灶,其中4例为单发,19例为多发,累及范围广泛,可累及额叶、顶叶、颞叶、枕叶、基底节丘脑区、小脑、脑干,病灶1.5cm者多出现占位效应。MRI表现:T1WI呈低信号,T2WI呈略高及不均匀高信号,有33(33/118,28.0%)个病灶周边呈等信号,而出现特征性"类靶征",T2WI-FLAIR呈等或略高信号,DWI及ADC呈略高信号;周围出现不同程度水肿反应;增强病灶≤0.8cm者多呈结节状强化,病灶0.8cm者多呈环状或靶样强化。结论艾滋病合并弓形虫脑炎的MRI表现为多发性,易累及大脑半球、基底节区及丘脑,病灶多呈类圆形结节,平扫T2WI可出现特征性"类靶征",增强扫描呈结节状、环状强化或靶样强化,具有一定的MRI表现特征。

Magnetic resonance imaging characteristics of toxoplasmosis encephalopathy in AIDS patients

Objective To explore the magnetic resonance imaging （MRI） characteristics of toxoplasmosis en- cephalopathy in AIDS patients, raise awareness of the disease, and reduce missed and delayed diagnosis. Methods A retrospective review was performed in 23 AIDS patients with toxoplasmosis encephalopathy. Results There were 118 lesions found in 23 patients, including four single and 19 multiple lesions. The lesions was extensive, involving frontal lobe, parietal lobe, temporal lobe, occipital lobe, basal ganglia, thalamus, cerebellum and brain stem. The mass effect would appear when the lesion diameter was more than 1.5 centimeters. For the MRI, all lesions were hypointense on Tl-weighted images, and slightly hyperintense on T2-weighted images （T2WI）. The edges of 33 lesions （28%） were isointense and looked like ＂target sign＂. The lesions were equisignal or slightly hyperintense on T2WI-FLAIR, DWI and ADC if there were edema reactions around the lesions. Post-contrast imaging revealed nod- ular enhancement when the lesion diameter was less than 0.8 centimeters, and ring or target enhancement when the lesion diameter was more than 0.8 centimeters. Conclusions The MRI of toxoplasmosis encephalopathy in AIDS patients showed multiple lesions. Many of the lesions involved the cerebral hemispheres, basal ganglia and thalamus. Many lesions were oval, showing as characteristic ＂target sign＂ on unenhanced T2WI, and as nodular, ring enhancement or target-like enhancement on enhanced scan.