Abstract: Objective To explore the value of diffusion-weighted imaging （DWI） and perfusion weighted imaging （PWI） in the differential diagnosis of atypical encephalitis and low-grade glioma. Methods The clinical and imaging data of 14 patients with atypical encephalitis and 31 patients with low-grade glioma in our hospital from May 2016 to December 2020 were retrospectively analyzed. Diffusion weighted imaging （DWI） and perfusion weighted imaging （PWI） were performed in all patients. Then the solid components of the lesions and the contralateral normal white matter were measured. The relative minimum apparent diffusion coefficient （rADCmin） and relative maximum cerebral blood volume （rCBVmax） were calculated. The differences of rADCmin and rCBVmax between the two groups were analyzed and compared. Results The rADCmin of atypical encephalitis group was higher than that of low-grade glioma group, and rCBVmax was lower than that of low grade glioma group（P<0.05）. The best threshold of rADCmin for differentiating atypical encephalitis from low grade glioma was 1.14, the sensitivity, specificity and area under the curve （AUC） were 96.77%, 90.00% and 0.903 respectively. The best threshold of rCBVmax for differentiating atypical encephalitis from low grade glioma was 2.26, the sensitivity, specificity and AUC were 64.52%, 100% and 0.726 respectively. Conclusion DWI and PWI are of great value in the differential diagnosis of atypical encephalitis and low-grade gliomas. DWI is superior to PWI in the diagnosis of atypical encephalitis.

Key words: encephalitis, low grade glioma, MRI, diffusion weighted imaging, perfusion weighted imaging

摘要： 目的 探讨磁共振扩散加权成像（DWI）和磁共振灌注加权成像（PWI）在非典型脑炎与低级别胶质瘤鉴别诊断中的价值。方法 回顾性分析2016年5月至2020年12月期间于我院就诊的14例非典型脑炎患者和31例低级别胶质瘤患者的临床及影像学资料,所有患者经影像学检查、生化检查及手术病理检查证实。所有患者均接受DWI和PWI检查,对病变实性成分和对侧镜像正常脑白质区进行测量,计算得出相对最小表观扩散系数值（rADCmin）和相对最大脑血容量值（rCBVmax）,比较两组间rADCmin和rCBVmax的差异性。结果 非典型脑炎组的rADCmin高于低级别胶质瘤组、rCBVmax低于低级别胶质瘤组（P<0.05）。rADCmin鉴别非典型脑炎和低级别胶质瘤的最佳阈值是1.14,敏感性、特异性和AUC分别为96.77%、90.00%和0.903;rCBVmax鉴别非典型脑炎和低级别胶质瘤的最佳阈值是2.26,敏感性、特异性和AUC分别为64.52%、100%和0.726。结论 DWI和PWI检查在非典型脑炎与低级别胶质瘤的鉴别诊断中具有重要的价值,DWI的诊断效能优于PWI。

关键词: 脑炎, 低级别胶质瘤, 磁共振成像, 扩散加权成像, 灌注加权成像