目的 探讨放射性脑损伤的影像 特征。方法 回顾分析我院环形强化放射 性脑损伤病例31例，按环开闭情况、环的 张力和形态演变、ASL-CBF灌注、DWI信号 分析。结果 ①4例呈闭环有张力；23例 呈闭环无张力；4例呈开环。②低灌注26 例；等灌注1例；边缘高灌注4例；③随时 间延长：环缩小的17例，增大的11例，不 变的3例；环形态不变的9例，变化的22 例；④DWI信号：11例高信号位于环内， 17例环形高信号，3例呈片状高信号。结 论 放射性脑损伤CBF多呈低灌注；脑外病 变放疗导致的放射性脑损伤DWI高信号位 于强化环内、强化环可逐渐增大但形态保 持不变。

Objective To discuss the imaging features of radiation-induced brain injury. Methods A retrospective analysis of 31 cases of radiation-induced brain injury in our hospital has been carried out. The MRI features were analyzed according to the open and closed ring, the tension and morphology changes of the ring,ASL-CBF perfusion and the DWI signal analysis. Results ①4 cases showed closed ring with tension. 23 cases with closed loop ring with no tension, 4 cases with open ring. ②26 cases presented low perfusion, perfusion in 1 case and edge part high perfusion in 4 cases. ③Rings of 17 cases reduced with time while 11 enlarged and 3 cases had no change. Besides,9 cases had no morphological changes while 22 cases had. ④DWI signal:high signal of 11 cases is located in the inner ring, 17 cases showed high signal and 3 cases were like patchy high signal. Conclusion The CBF present low perfusion in MRI mostly; The brain damage caused by brain external lesions showed the DWI high signal is located in the inner enhancement ring, it can increased with time, but the shape didn't change.