Abstract: Objective To explore the application value of diffusion weighted imaging (DWI) combined with computed tomography angiography (CTA) in preoperative evaluation of meningiomas. 
Methods A total of 127 patients with meningioma who underwent surgical treatment at Nanchong Hospital of Beijing Anzhen Hospital, Capital Medical University, (Nanchong Central Hospital) were selected as the research subjects. All patients underwent preoperative DWI and CTA, and tumor imaging features and related parameters were recorded. After surgery, pathological examination of the tumor tissue was performed, and based on the examination results the tumor was divided into low-grade and high-grade meningiomas. The imaging features, apparent diffusion coefficient (ADC) and mean cycle threshold (CT) value of DWI and CTA in patients with different grades of meningioma were compared, and the receiver operating characteristic (ROC) curve was used to analyze the application value of DWI parameter ADC and CTA parameter mean CT value in preoperative evaluation of meningioma. 
Results The results of postoperative histopathological examination showed that there were 97 patients with low-grade meningioma (WHO grade I) in 127 patients, accounting for 76.38%, and 7 patients with high-grade meningiomas (WHO grade Ⅱ-Ⅲ), accounting for 5.51%. DWI and CTA imaging features of meningiomas in different diseases were significantly different. The ADC value of tumor tissue in low-grade meningioma patients ［(0.80±0.08)×10-3mm2/s］ was higher than that in high-grade meningioma patients ［(0.70±0.05)×10-3mm2/s］, and the average CT value in low-grade meningioma patients ［(57.81±5.34) Hu］ was lower than that in high-grade meningioma patients ［(63.12±10.30) Hu］, with a significant difference (P＜0.05). The area under the ROC curve of DWI parameter ADC and CTA parameter mean CT value alone and in combination in preoperative evaluation of meningioma grade was 0.855, 0.702 and 0.864, respectively, which had certain evaluation value. 
Conclusion The combination of DWI and CTA has good application value in preoperative evaluation of meningiomas, which is beneficial for improving the accuracy of differentiation between low-grade and high-grade meningiomas. 

Key words: meningioma, computed tomography angiography, diffusion weighted imaging