摘要目的 探讨双侧颞叶脑组织在鼻咽癌放射治疗后不同时期的DTI与1H-MRS变化特点.方法 选择48例鼻咽癌放射治疗后常规MRI表现正常的患者(患者组)及24名健康志愿者(正常组)行DTI及1H-MRS检查,将扫描图像进行后处理和波谱分析,测量双侧颞叶DTI的各向异性分数(FA)值、ADC值及3个本征值λ1、λ2、λ3,以及1H-MRS中双侧颞叶前部白质N-乙酰天冬氨酸(NAA)/胆碱(Cho)、NAA/肌酸(Cr)及Cho/Cr比值,并将鼻咽癌放射治疗后患者按放射治疗后不同时期分为放射治疗后0～6、6～12、>12个月,分别定义为患者组1(16例)、2(6例)、3(26例),计算放射治疗后双侧颞叶脑组织各测量指标数值.所得数据采用单因素方差分析.结果 鼻咽癌放射治疗后6个月内、6～12个月、12个月后以及正常组DTI的FA值分别为0.445±0.017、0.460±0.016、0.461±0.025、0.473±0.023,ADC值分别为(8.51±0.43)×10-4、(8.48±0.34)×10-4、(8.40±0.33)×10-4、(8.68±0.57)×10-4mm2/s,3个本征值中最大本征值λ1分别为(1.251±0.065)×10-3、(1.293±0.051)×10-3、(1.317±0.074)×10-3、(1.350±0.091)×10-3 mm2/s,以上3个指标组间差异均有统计学意义(F值分别为10.873、3.399、9.750,P值均<0.05).λ2、λ3值组间比较差异无统计学意义.1H-MRS的NAA/Cho分别为0.910±0.112、0.972±0.101、1.060±0.095、1.261±0.105,NAA/Cr分别为1.212±0.236、1.208±0.183、1.228±0.236、1.435±0.225,组间差异均有统计学意义(F值分别为52.840、8.176,P值均<0.01).Cho/Cr组间比较差异无统计学意义.结论 DTI结合1H-MRS在鼻咽癌放射治疗后监测评价脑组织的放射损伤程度方面具有一定的指导作用,可为放射性脑损伤的动态早期监测提供科学依据.

abstractsObjective To investigate the changes of brain tissue in bilateral temporal lobes at different stages after nasopharyngeal carcinoma radiotherapy by diffusion tensor imaging(DTI)and 1H-MR spectroscopy(1H-MRS).Methods DTI and 1H-MRS were performed in 48 patients with nasopharyngeal carcinoma.in which conventional MRI revealed normal findings after radiotherapy.Twenty-four healthy controls were enrolled in this study and underwent the galne MR scanning.After the image processing and spectral analysis,apparent diffusion coefficient(ADC),fractional anisotropy(FA) and 3 eigenvalue λ1,λ2,λ3 of DTI and the NAA/Cho,NAA/Cr,Cho/Cr of 1H-MRS were measured in bilateral temporal lobes.Forty-eight NPC patients were divided into 3 groups [ less than 6 months(16 cases),6 to 12 months (6 cases)and more than 12 months(26 cases)after radiotherapy]according to different stages of radiationinduced injury of brain.each group's DTI and 1H-MRS data were measured respectively and one-way ANOVA was applied to analyze each parameter. Results The FA value of each test group(less than 6 months.6 to 12 months and more than 12 months)and the control group were 0.445±0.017,0.460±0.016,0.461±0.025,0.473±0.023 respectively.The ADC values of each group were(8.51±0.43)×10-4.(8.48±0.34)×10-4,(8.40±0.33)×10-4,(8.68±0.57)×10-4mm2/s respectively.And the maximum eigenvalue λ1 of each group were(1.251±0.065)× 10-3,(1.293±0.051)×10-3,(1.317±0.074)×10-3,(1.350±0.091)× 10-3mm2/s.The three indicators were significantly difrerent among groups(F=10.873,3.399,9.750 respectively,P<0.05).λ2,λ3 values showed no significant difference among the groups.The NAA/Cho of 1H-MRS of each groups were0.910±0.112,0.972±0.101,1.060±0.095,1.261±0.105 respectively,and the NAA/Cr were 1.212±0.236,1.208±0.183,1.228±0.236,1.435±0.225 respectively.Both of them had significant differences among groups(F=52.840,8.176 respectively,P<0.01).Cho/Cr showed no significant difference among the groups.Conclusions DTI combining with 1H-MRS play a certain guiding role on monitoring and evaluating of radiation injury of brain tissue in nasopharyngeal carcinoma after radiotherapy.It Can provide a scientific basis for the dynamic monitoring of radiation brain injury.