先天性耳聋患儿听觉中枢及传导通路弥散张量成像和频谱研究

The study of diffusion tensor imaging and MR spectroscopy in the auditory center and relevant anatomy of auditory pathway in children with congenital sensorineural hearing-loss

目的利用磁共振弥散张量成像(DTI)及频谱(MRS)探讨先天性耳聋患儿听皮质及听辐射的微观结构及脑代谢物变化。方法 82例先天性耳聋患儿[年龄7个月至14岁,平均(4.34±3.32)岁]及31例听力正常儿童分别进行头部常规MR、DTI及MRS检查,测量双侧颞上回、听辐射区域表观弥散系数(ADC)值、部分各向异性(FA)值,定量分析双侧颞上回代谢物如N-乙酰天冬氨酸(NAA)、胆碱(Cho)、肌酸(Cr)以及NAA/Cr比值的变化。耳聋组及正常对照组按年龄再分成≤3岁(43例)及>3岁(39例)两亚组并进行组间比较。统计学分析采用两独立样本t检验。结果耳聋组与正常组比较,两组间听辐射FA值、颞上回FA值存在统计学差异(t值分别为12.895、3.264,均P<0.05),按年龄分组对比,其中≤3岁组FA值仅听辐射组间差异有统计学意义(t=7.961,P<0.05),而>3岁组,听辐射、颞上回FA值、颞上回NAA/Cr组间差异均存在统计学意义(t值分别为10.328、3.233、2.206,均P<0.05)。结论耳聋患儿DTI及MRS可定量检测出脑部听觉中枢及通路髓鞘发育及神经元细胞代谢的改变。

Objective To study the changes of microstructure and metabolites in auditory cortex and auditory radiation in children with congenital sensorineural hearing-loss（SNHL） by diffusion tensor imaging （DTI） and MR spectroscopy （MRS）. Methods Eighty-two individuals [ range 7 months to 14 years, mean age（4. 34 ± 3. 32 ）years] with congenital SNHL and thirty-one age matched normal hearing subjects received conventional MRI, DTI and MRS examination of the brain. Values of the fractional anisotropy （FA） and apparent diffusion coefficient （ ADC ） in the superior temporal gyrus （ STG ） and auditory radiation were measured bilaterally, and metabo]ites such as N acetyl aspartate （ NAA ）, choline （ Cho）, creatine （Cr） and NAA/Cr in both side of superior temporal gyrus were calculated in all subjects. Meanwhile, the SNHL patients and the healthy controls were divided into two subgroups： Group A （ ≤3 years ） and Group B （ 〉 3 years）. The difference between SNHL patients and the healthy controls groups was compared by Student＇s t test. P 〈 0. 05 was considered significant. Results There was statistically difference in FA of the auditory radiation and STG between 82 SNHL patients and 31 healthy controls（t = 12. 895,3. 264,both P 〈0. 05）. In group A,the reduction in FA values of the auditory radiation was significantly different from the control（ t = 7. 961 ,P 〈0. 05） ,and in group B,compared to healthy controls,there were not only significantly differences in FA values of the auditory radiation and STG,but also in NAA/Cr of STG（ t = 10. 328,3.233,2. 206,all P 〈 0. 05 ）. Conclusion Combined DTI and MRS can provide quantitative detection of the myelination of the auditory center and auditory pathway, and the regional metabolic of the brain.