三叉神经桥池段:三维断层解剖与MRI对照研究

目的：通过头颅三维断层标本与ＭＲＩ对照研究三叉神经桥池段，为影像学诊断提供解剖学依据。方法：利用头颅三维连续断层标本３５套、正常成人头颅ＭＲ检查１０３例和增强ＭＲ检查３６例，观察和测量三叉神经桥池段的形态、大小及周围血管关系。结果：三叉神经桥池段由后向前逐渐增粗，形态由圆形和椭圆形变为扁椭圆形；三叉神经根进入区（ＲＥＺ）的内上方有小脑上动脉行走，与ＲＥＺ相接触者在标本和ＭＲＩ上分别占１１．４％和１０．７％，ＲＥＺ下方有小脑下前动脉行走，与ＲＥＺ相接触者在标本和ＭＲＩ上各占７．１％和６．８％；３８％的ＲＥＺ和３５％的节前段（ＰＧＳ）两侧不等高，相差１～４ｍｍ；正常三叉神经桥池段无增强效应。结论：ＭＲＩ能清晰显示三叉神经桥池段，全程显示矢状位与轴位同样满意，冠状位对桥池段的间距、高度、形态和周围血管关系的显示最佳。

Pontine Cistern Segment of Trigeminal Nerve:A Compartive StudyBetween Three-dimensional Cadaver Sections and MR Images

Objective:To provide the anatomic data for imaging diagnosis of pontine cistern segment of trigeminal nerve,by a comparative study between three-dimensional cadaver sections and MR images.Methods:The shape,size and surrounding vessels were observed and measured on 35 sets of serial cross,coronal and sagittal sections of cadaver heads and 103 individuals of unenhanced MR imaging and 36 cases of enhanced MR imaging.Results:The pontine cistern segment of trigeminal nerve becomes wider and flatter as it passes through the REZ to the PEZ.11.4% on sections and 10.7% on MR images showed superomedial vessel contact at the REZ by the superior cerebellar artery and 7.1% on sections and 6.8% on MR images inferior contact at the REZ by the anterior inferior cerebellar artery.On MR images,the trigeminal nerves of both sides were not at the same level (difference of 1 to 4 mm) at 38% of REZs and 35% of PGSs.On enhanced MRI,normal pontine cistern segments were not enhanced.Conclusion:MRI can show the pontine cistern segment in detail.Sagittal MRI can show whole segment satisfactorily as same as the cross.Coronal MRI is optimal slices to show the distance,height,shape,and adjacent vessels of pontine cistern segment.