视神经和视交叉冠状断层解剖与MRI

目的：研究视神经和视交叉在冠状断面上的解剖特征与MRI表现，为相关疾病的影像诊断和外科手术提供解剖学资料。方法：选取15例成人尸头标本，以冷冻切片法切制成连续冠状断层标本；应用3．0TMRI扫描仪，获取10例志愿者头部的sE序列T1WI和T2WI图像；在上述断层标本和MRI图像上，观察分析冠状断面上视神经的形态、位置和毗邻关系。结果：视神经眶内段居于眶中心偏内上方，断面呈圆形，其周围有视神经鞘包绕，蛛网膜下隙清晰可见，眼动脉位于其上方；视神经管内段居于眶内上方,断面呈水平卵圆形，周围可见视神经鞘，蛛网膜下隙不明显，眼动脉位于其下方；视交叉冠状断面呈“一”字型，分隔上方的视隐窝和后下方的漏斗隐窝，其上方有大脑前动脉A1段，下方为灰结节和垂体柄。结论：冠状断面町以清楚显示视神经、视交叉的形态特点与毗邻关系。

Sectional Anatomy and MRI of the Optic Nerve and Optic Chiasm on the Coronal Plane

Objective：To describe the anatomical features and MR imaging of the optic nerve and optic chiasma on the coronal section in order to provide anatomic data for imaging diagnosis and surgical operation of the diseases in this area. Methods：The location and adjacent structures of the optic nerve and optic chiasma on the coronal plane was investigated on 15 sets of serial coronal sections of the heads of Chinese adult cadavers and 10 sets of serial coronal MR] of normal adults. Results：The intraorbital segment of optic nerve located me- dial superior to the center of orbit and below the ophthalmic artery, which was surrounded by the subarachnoid space and the sheath of the optic nerve. The shape of the intraorbital segment of optic nerve was round on the coronal sections. The intracanalicular segment of optic nerve located superior to the orbit and above the ophthal- mic artery, which was surrounded by the sheath of the optic nerve. The shape of the intracanalieular segment of optic nerve was horizontal oval on the coronal sections. The optic chiasm transversed between the optic and in- fundibular recesses, lying below the segment AI of the anterior cerebral artery and above the tuber cinereum and pituitary stalk. The MRI images matched well with the sectional anatomy of the optic nerve and optic chi- asm. Conclusions：The coronal plane can accurately demonstrate the location and the adjacent relations to sur- rounding tissues of the optic nerve and optic chiasma.