高b值扩散加权成像在颅内脑膜瘤诊断中的价值

Value of high b-value diffusion weighted imaging in diagnosis of intracranial meningiomas

目的探讨磁共振高b值扩散加权成像(DWI)在颅内脑膜瘤诊断中的价值。方法回顾分析我院36例经临床诊断或组织学证实的脑膜瘤患者(21例良性,15例恶性)的常规磁共振影像,以及在b=1000s/mm2和b=2000s/mm2的扩散加权成像获得两个b值的表观扩散系数(ADC)图。计算肿瘤实体组织、对侧正常组织、瘤旁水肿的信号强度(SI)、ADC值和标准表观扩散系数(NADC)值,对两个b值下的DWI图像与临床诊断或组织学检查结果进行比较分析。结果b=2000s/mm2比b=1000s/mm2的DWI的图像对比度更高,对病变边界显示更清晰、定位更准确;恶性脑膜瘤在两个b值下的平均ADC值明显低于良性脑膜瘤;恶性脑膜瘤两个b值的平均NADC比值也明显低于良性脑膜瘤(P<0.05)。结论高b值扩散加权成像能提高脑膜瘤的良恶性鉴别能力,在脑膜瘤的术前影像学评价中有重要作用,可为治疗方案的选择提供影像学依据。

Objective To explore the value of high B-value diffusion weighted imaging （DWI） in diagnosis of intracranial meningiomas. Methods A retrospective analysis was made on the conventional magnetic resonance imaging of 36 patients with meningiomas clinically diagnosed or histologically confirmed in our hospital （benign n = 21 and malignant n = 15 ） and the apparent diffusion coefficient （ADC） imaging of two b values obtained from diffusion weighted imaging at b = 1,000 s/mm^2 and b= 2,000 s/mm^2. The tumor tissue, normal contralateral tissue, peritumoral edema signal intensity （ SI ）, ADC values and normal apparent diffusion coefficient （NADC） values were calculated and the DWI of two b values and the clinical diagnosis or histological examination results were compared and analyzed. Results The contrast of DWI from b = 2,000 s/mm^2 was higher than that from b = 1, 000 s/mm^2and the lesion boundary can be showed more clearly and the positioning was more accurately; the average ADC values of malignant meningioma obtained from the two b values were significantly lower than those of benign meningioma and the average NADC ratios of malignant meningioma from the two b values were also significantly lower than those of benign meningiomas （ P 〈 0.05 ）. Conclusion The high b-value DWI can improve the ability to discriminate benign and malignant meningiomas; it plays an important role in preoperative imaging evaluation and can provide imaging basis for the selection of treatment method for meningioma.