鼻咽癌放疗后放射性脑损伤的MRI分析

MRI Analysis of Radiation Encephalopathy After Radiotherapy in Nasopharyngeal Carcinoma

【目的】提高鼻咽癌放疗后放射性脑损伤(radiation encephalopathy,REP)的MRI表现的认识。【方法】对56例鼻咽癌放射治疗后放射性脑损伤患者的MRI表现进行分析。【结果】放射性脑损伤50例单纯发生于颞叶,病变累及双侧31例,单侧19例。MRI表现为:①弥漫水肿型18例:呈指状水肿灶,Gd-DTPA增强扫描无强化;②局灶性坏死型25例:表现为稍长T1长T2结节或团块灶。增强扫描可见病灶明显环形强化,呈皱缩状,花边状;③局灶性囊变型7例:增强后T1WI扫描囊壁无或有强化。脑干受损者6例,呈等或长T1长T2小病灶,增强扫描可见点状或不规则环状强化。【结论】MRI能清楚显示鼻咽癌放疗后放射性脑损伤的的范围和程度,其MRI表现有一定的特征性。

[Objective]To improve the cognition of MRI finding of radiation encephalopathy after radiotherapy in nasopharyngeal carcinoma. [Methods]MRI finding of fifty-six patients with radiation encephalopathy after radiotherapy in nasopharyngeal carcinoma was analysed. [Results]The lesion of 50 patients occurred in the temporal lobes.mainly in the bilateral or unilateral temporal lobes , There were three typical MRI features： ①diffuse edema was observed in 18 lesions. MRI showed finger edema, T1 WI plus Gd-DTPA showed no enhancement.②Local necrosis was observed in 25 lesions. MRI showed node or lump with hypo-intensity signal on T1WI and hyper-intensity signal on T1WI ,and lesions with T1WI plus Gd-DTPA showed distinct rings of enhancement in the form of crimple and flower-lace. ③Local cyst was observed in 7 lesions. T1WI plus Gd-DTPA showed enhancement or no enhancement on the cystic wall. Six patients had an encephalopathy in the pons of brain stem. MRI in T1WI of these patients showed low signal intensity or iso-signal intensity whereas T2WI showed high signal intensity, and lesions with T1WI plus Gd-DTPA showed irregular rings of enhancement. [Conclusion]MRI can provide accurate assessment of the location and extent of REP, The MRI findings are characteristic in radiation-induced encephalopathy observed in nasopharyngeal carcinoma patients.