MRI在低恶度脑胶质瘤伽玛刀术后评价中的应用价值

Value for MRI on low-grade glioma in brain after Gamma knife radiosurgery

目的探讨低恶度脑胶质瘤(Ⅰ-Ⅱ级)伽玛刀术后疗效的评价以及MRI在评价中的应用价值。方法52名低恶度脑胶质瘤患者行伽玛刀治疗,术后应用MRI进行随访复查,对获得的140份资料进行分析,根据术后病灶大小变化评价术后各个阶段的疗效,并研究病灶术后强化反应的特征,及长期随访后的转归。同时,与相应的46份CT资料相对比,研究MRI在病灶情况显示中的优势。结果术后分时间段计算的显效率分别为30%,36.4%,50%,68%,69.2%和73.1%。病灶增大与MRI强化及坏死囊变存在关联。32.7%患者伽玛刀治疗后出现放射性水肿。57.7%患者出现术后MRI强化,以花边状强化为特征,也可呈斑片状。80%患者在术后1年内首次出现MRI强化,随后部分病例的MRI强化可缩小或消失。强化出现与病灶增大及灶周水肿加重呈正相关。强化范围增大与病灶的坏死囊变呈正相关。MRI对病灶边界及病灶内强化及灶周水肿的显示较CT优越。结论伽玛刀治疗低级别脑胶质瘤具有一定的疗效。MRI反映的放射治疗后变化有大小变化、MRI强化、坏死囊变、放射性水肿。MRI强化大多为放射反应性强化,与其它各因素间存在密切的关联,其花边状强化具特异性。在病灶情况显示及疗效评价上MR明显优于CT。

Objective To study therapeutic effect for low-grade glioma in brain after Gamma knife radiosurgery and the value for MRI on therapeutic effect evaluation. Methods To analyze 140 cases MRI for 52 low-grade glioma patients after gamma knife radiosurgery by observing tumor size for staged therapeutic effect, radiobiological effect of contrast enhancement and turnover for long-term follow up. Results The staged therapeutic effect rate is 30%, 36.4%, 50%, 68%, 69.2%, 73.1% respectively. The accretion of tumor related to MRI contrast enhancement and necrotic or cystic area. Radiobiological oedema occurs for 32.7%. The MRI contrast enhancement occurs for 57.7% and shows mostly special lace-like ring while others piece-like. It is related to the accretion, oedema aggravation and necrotic or cystic area of tumor. Contrast enhancement occurs for 80% in the first year after the radio- surgery and some disappears later. MRI is saperior to CT in detection. Conclusion The therapeutic effect is predominance. The Radiobiological effect usually shows postoperation MRI contrast enhancement, accretion, oedema, necroticor cystic area of tumor. Contrast enhancement shows mostly special lace-like ring and is related with other factors. MRI is superior to CT in detection and therapeutic effect valuation.