Objective To evaluate application value of apparent diffusion coefficient (ADC) in differentiating brain radiation-injuries and glioma recurrence. Methods Totally 23 patients [18 men and 5 women aged 32 to 67 years (mean; 47 years) ] with previously resected and irradiated glioma were examined by using a 3. 0T MR Scanner, including conventional and diffusion weighted image ( DWI) sequences. All the cases were proved by pathology or clinical follow-up. Postprocessing of ADC maps was performed by using Functool software ( AW 4. 3 , GE Healthcare) , and the regions of interest ( ROIs) were manually drawn on ADC maps in the area corresponding to the contrast-enhancing area on post-contrast axial Tl -weighted images, avoiding the hemorrhage or necrosis. The ADC values were calculated automatically. ADC values were measured 10 times in order to reduce errors, and mean ADC value, maximum ADC value, and minimum ADC value were acquired. Results Both recurrent glioma and irradiated necrosis tended to have hemorrhage, necrosis, and edema. The mean ADC value and maximum ADC value were lower in the recurrent tumor group than in the radiation-injuries group, but no statistical difference was achieved. However, the minimum ADC value was significantly lower in the recurrent tumor group than in the radiation-injuries group (P=0. 016). Conclusion The minimum ADC value can be used as an useful tool in differentiating tumor recurrence from radiation-injuries.%目的 分析表观弥散系数(ADC)值在鉴别脑胶质瘤复发与放射性脑损伤中的作用.方法 采用3.0T磁共振扫描机,对23例脑胶质瘤术后放疗后的患者(随访中出现异常强化灶)行脑部常规MRI检查及弥散加权成像(DWI)检查,23例患者均经二次手术或随访证实为胶质瘤复发或放射性脑损伤.DWI原始数据采用Functool软件进行ADC值测量,感兴趣区(ROIs)放置在病灶中DWI信号均匀处,并参考增强T1WI以避开出血及液化坏死区.所选ROI的ADC值由Functool自动计算出,为了减少误差,在强化病灶内测量10处ADC值,得到平均值、最大值及最小值.结果 胶质瘤复发及放射性脑损伤病灶中均常见出血、坏死、水肿等,导致ADC值具有较大差异.胶质瘤复发组平均ADC值及最大ADC值均小于放射性脑损伤组,但差异无统计学意义,而胶质瘤复发组最小ADC值明显小于放射性脑损伤组(P=0.016).结论 最小ADC值在鉴别胶质瘤复发与放射性脑损伤中有一定的意义.
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