1H - MRS及DWI对脑星形细胞瘤放疗疗效评估的研究

目的:评价1H - MRS及DWI两种磁共振功能成像对脑星形细胞瘤放疗疗效的应用价值.方法:低级星形细胞瘤(WHO Ⅰ～Ⅱ级)12例、高级(WHOⅢ～Ⅳ级)8例,均在手术后2～4wk内放疗.先行T1 WI、T2WI、DWI及增强扫描,增强后48h行1H -MRS检查.病灶实体区及正常区的Cho、NAA、Cr、ADC相除分别得到rCho、rNAA、rCr、rADC.放疗前(1wk内)、放疗后1mo和3mo分别测量rCho/rCr、rCho/rNAA、rADC.并计算rCho/rCr,rCho/rNAA和rADC放疗后1mo和3mo与放疗前的平均差值分别为1和2.两组病人分别进行.结果:1、低级别组:rCho/rCr、rCho/rNAA、rADC放疗后3mo与放疗前有统计学差异(P ＜0.05)；rCho/rCr、rCho/rNAA放疗后3mo与放疗后1mo有统计学差异(P＜0.05).rCho/rCr、rCho/rNAA、rADC平均差值1及平均差值2有统计学差异(P＜0.05).2、高级别组无一定的规律.结论:对于低级别星形细胞瘤1H -MRS、DWI可了解肿瘤内部代谢情况,早于常规形态学发现肿瘤对放疗的反应,有助于确定进一步的治疗方案.本组高级别星形细胞瘤资料差异较大,没有明显的规律性,有待进一步研究.

EVALUATION OF RADIOTHERAPY FOR ASTROCYTOMA WITH 1 H- MRS AND DWI

Objective: To assess proton magnetic resonance spectroscopy(1H-MRS) and apparent diffusion coefficient(ADC)in evaluation of cerebral astrocytoma radiotherapy response.Methods:Twenty post-operation patients with histologically proven brain astrocytoma included 12 low grade and 8 high grade which were selected in the study.T1WI、T2WI、contrast enhanced MRI,1H-MRS(PRESS,TR/TE=1000/144ms)and DWI(b=0and1000s/mm2)were performed before or one and three months after the treatment,named as phase 1,2 and 3.The metabolite peak area of N-acetylaspartale,choline and creatine compounds were measured in the tumour mass and normal area.The ratios of NAA,Cho,Cr,and ADC in tumour and control areas were defined as rNAA,rCho,rCr,rADC respectively.The values in three phases and in the patients with different tumour grades were compared.Results: There were significant differences in rCho/rCr rCho/rNAA and rADC between phase 1,2 and 3 in the low-grade group.However,there were no obvious patterns in the high-grade group tumour patients.Conclusions: 1H-MRS and ADC may be used as the early indicators for radiotherapy responses in low grade astrocytoma,but not in high grade brain tumour.