14～40周胎儿脑干发育的高场强MRI研究

目的:应用高场强MRI探讨胎儿脑干发育规律.方法:选取85例14～40孕周胎儿标本,均行3.0 T MR扫描,其中20例加行7.0 T MR扫描,并在扫描图像上应用eFilm软件测量脑干下述各径线的数值.① 脑干前后径,采用4条径线表示.A线,大脑脚前缘中点与中脑水管中点间距离;B线,脑桥前缘中点与第四脑室底最短距离;C线,脑桥与延髓移行部的最短距离;D线,延髓与脊髓移行部的最短距离.② 脑干长径,采用3条径线表示.E线,大脑脚长轴距离;F线,脑桥长轴距离;G线,延髓长轴距离.结果:各径线测量值随胎龄增长呈线性增加,依据线的斜率可知脑干内部各结构以不同速度增长.F线增长最快,D线增长最慢.A线和E线几乎保持相同的增长速度,B线和F线也几乎保持同样的增长速度.结论:高场强MRI可以清晰显示胎儿脑干解剖结构,为临床评价正常胎儿脑干发育提供了形态学基础.

High Field MRI Study on the Development of Fetal Brain Stem of 14-40 Weeks Gestational Age

Objective：To investigate the developmental rules of fetal brain stem with high field MRI. Methods：85 fetal specimens of 14 -40 weeks gestational age were scanned by 3. 0 T MRI, and 20 fetal specimens of 14 - 22 weeks gestational age was also scanned by 7.0 T MRI. The diameters of the brain stem were obtained with eFilm software on the above MRIs. The measurements were as follows ： ① The anteroposterior diameters of the brain stem, which included 4 lines ： line A ： the distance between the midpoint of anterior border of the cerebral peduncle and midpoint of the midbrain aqueduct ; line B ： the shortest distance between the midpoint of anterior border of the pons and basement of the fourth ventricle; line C： the shortest distance of the transitional part between the pons and medulla ; line D ： the shortest distance of the transitional pm＇t between the medulla and spinal cord. ② The long diameters of the brain stem, which included 3 lines： line E： length of long diameter of the cerebral peduncle ; line F ： length of long diameter of the pons ; line G： length of long diameter of the medulla. Results：Each diameter linearly increased with gestational age. The slopes of lines suggested that the internal structures of the brain stem grew at different rates. Line F grew fastest, and line D grew slowest. Line A and line E almost had the same growth rate, fine B and fine F also had the same growth rate. Conclusions：High field MRI can clearly show the anatomy of fetal brain stem. The results of this study can provide a morphological reference for the assessment of normal fetal brain stem development in clinical settings.