神經醫學影像論壇邀您來診斷（三）答案

06-13

History:HIV-positive woman with severe headache, nausea, vomiting, and fever.

（HIV陽性婦女伴有嚴重頭痛、噁心、嘔吐和發燒。）

正確答案：弓形蟲病

Toxoplasmosis of the CNS

Toxoplasmosis is the most common opportunistic CNS infection in patient"s with AIDS (about 10% of AIDS patient"s will develop this infection). The routes of transmission include ingestion of the tachyzoites (ingestion of uncooked meats) or oocysts (ingestion of feces-contaminated food), transplacental, transfusions, and organ transplants. More than 50% of the adult population in the US have antibodies to Toxoplasma. Acute toxoplasmosis in an immunocompromised patient usually occurs through the reactivation of a latent infection. The most common areas affected within the brain include the basal ganglia and the cortical medullary junctions. These lesions are usually associated with a moderate amount of edema and mass effect.（弓形蟲病是艾滋病患者最常見的機會性中樞神經系統感染（約有10%的艾滋病患者會感染這種疾病）。傳播途徑包括弓形蟲速殖子（未煮熟的肉類攝入）或卵囊（糞便污染的食物的攝入）、胎盤、輸血、器官移植。美國成年人口中有超過50%的人有弓形蟲抗體。免疫低下患者的急性弓形蟲通常是通過潛伏感染再次發生。大腦內最常見的區域包括基底節區和皮髓交界區。這些病變通常伴有中度水腫和佔位效應。）

Toxoplasmosis lesions tend to occur in the basal ganglia and cortical medullary junctions.Toxoplasmosis on a CT scan typically appears as a single or multiple ring-enhancing lesions with a moderate amount of peripheral edema.

On T1-weighted images, the lesions are hypointense relative to graymatter. On T2-weighted images , the lesions are hyperintense ,or occasionally isointense to hypointense. Surrounding edema is usually seen. Nodular or ring enhancement can be seen in approximately 70% of patients following intravenous injection of gadolinium.（弓形體病往往發生在基底節和皮髓交界區，CT上弓形蟲通常表現為單個或多個環形強化病變，並伴有中等程度的周圍水腫。T1加權像病灶相對於灰質呈低信號。在T2加權像呈高信號或偶爾呈中等偏低信號，通常可見周圍水腫。靜脈注射釓劑後約70%的患者可見結節狀或環狀強化。）