磁共振增强减影技术在结核性脑膜炎中的运用

目的评价磁共振增强减影方法在结核性脑膜炎中的应用价值。方法对30例结核性脑膜炎患者进行磁共振检查，对增强前后T1加权图像行减影处理。在不同的解剖层面，随机选取120处异常强化柔脑膜在常规增强T1加权和减影图像中分另Ⅱ进行长度及相对信号强度测量，所获数据用统计软件进行分析，评价并比较异常强化柔脑膜在减影图像与常规增强T1WI中的显示。结果磁共振减影图像比常规增强T1Wi显示异常强化柔脑膜更清晰、直观。减影图像显示异常强化柔脑膜多呈连续状，而常规增强T1加权图像大多呈断片状，2种成像方法显示异常强化柔脑膜的长度有显著性差异（P〈0．01）。减影图像中异常强化柔脑膜信号强度相对比值明显高于常规增强T1W1，其差异有极显著性意义（P〈0．01）。结论磁共振增强减影技术是一种能明显提高结脑异常强化柔脑膜显示率的简便方法，可为临床早期诊断结脑提供一个全新的诊断工具。

Application of MR contrast-enhanced subtraction in tuberculous meningitis

Objective To assess the clinical application of MRI contrast-enhanced subtraction in tuberculous meningitis (TBM). Methods Thirty patients with TBM were examined by using MRI with T1-weighted MR sequences before and after intravenous administration of Gd-DTPA, and digital subtraction was performed on selected images. One hundred and twenty abnormally enhanced meninges were randomly selected on both post-contrast T1WI and subtraction images, and the maximum length and the relative signal intensities were measured respectively on subtraction images and conventional contrast-enhanced T1WI in those 120 different anatomic levels. The data were analyzed with statistical software. Imaging findings were compared between subtraction images and conventional contrast-enhanced MRI. Results Subtraction images were better than routine contrast-enhanced MRI in demonstrating the abnormal meninges. The abnormal enhanced meninges showed continuous enhancement patterns on subtraction images, while short segmental enhancement was most frequently observed on routine contrast-enhanced T1WI. The abnormal meningeal enhancement length showed statistical difference between the two different imaging methods (P<0.01). All the meningeal lesions had higher relative signal intensities on subtraction images than on routine contrast-enhanced MRI (P<0.01). Conclusion MR contrast-enhanced subtraction technique is an important and easy postprocessing method which can improve the demonstration of meningeal abnormalities in TBM, and thus it can be recommended as the early diagnostic tool for TBM.