磁共振成像在早产儿白色念珠菌感染脑脓肿诊断中的意义

Value of MRI in the diagnosis of cerebral abscess caused by Candida albicans in premature infants

摘要:

目的：探讨磁共振成像在中枢神经系统侵袭性真菌感染（IFI）致脑脓肿中的诊断价值。方法：回顾性分析8例中枢神经系统IFI早产儿临床资料，8例患儿于住院期间和出院后接受了MRI T1WI、T2WI和DWI 3种序列头部检查。结果：8例IFI早产儿均为白色念珠菌感染。其中7例表现为脑脓肿，4例伴有脑膜炎。7例脑脓肿患儿MRI提示侵袭范围广泛，皮层下白质、深部脑室周围及半卵圆中心白质受累。其中4例MRI检查在感染后11 d内完成，表现为弥漫或多发粟粒样结节，DWI呈高信号，而T1WI和T2WI改变不明显，DWI信号3周后近消失；在感染的2~4周T1WI/T2WI信号改变最明显，结节可呈环形，T1WI周边为高信号，中央低信号，T2WI信号与之相反，严重者表现不同程度的融合，在T1WI可见明显强化效应。4周后病灶在T1WI也逐渐变少和变小，转为点或线样的高信号，T2WI明显低信号。2例MRI动态随访表现有髓鞘发育延迟，胼胝体变薄。结论：MRI-DWI和动态的MRI改变可为早产儿白色念珠菌感染脑脓肿的早期诊断及治疗转归评估提供客观依据。

Abstract:

OBJECTIVE: To explore the value of serial magnetic resonance imaging (MRI) in the diagnosis of cerebral abscess caused by Candida albicans in premature infants. METHODS: The clinical data of 8 premature infants with central nervous system invasive fungal infection (IFI) were retrospectively studied. The infants underwent serial cerebral MRI scans (T1WI, T2WI and DWI). RESULTS: Candida albicans was found as pathogen in all of the 8 infants. Seven infants presented with cerebral abscess and 4 infants had concurrent meningitis. Widespread involvements were found on MRI, particular in white matter area of subcortex, centrum semiovale and periventricle. The MR imaging findings in 4 infants within 11 days after IFI showed diffusive and multiple miliary nodes and hyperintense signals on DWI, but obvious changes were not found on T1WI and T2WI. The most striking hyperintense signals on T1WI and hypointense signals on T2WI appeared between 2 and 4 weeks after IFI, and some nodes of rim-like hyperintensity and marked contrast enhancement were also noted on T1WI. Smaller and smaller changes of the miliary foci were seen on T1WI and T2WI 4 weeks later. Delayed myelination and thinner corpus callous were shown in 2 patients at three months. CONCLUSIONS: MRI-DWI and serial MRIs are helpful in the early diagnosis of candida cerebral abscess and the evaluation of treatment outcome in premature infants.