视神经磁共振成像方法研究

Study of Magnetic Resonance Imaging of Optic Nerve

目的 探讨视神经磁共振 (MRI)成像最佳方法及正常视神经MRI征象 .方法 随机选择 4 0例进行头部检查 ,无眼部疾患或视力障碍患者作为正常视神经研究对象 .使用PhilipsACS -NT15 1.5T超导型磁共振成像仪及正交头线圈 .成像序列包括自旋回波T1加权成像 (SET1WI)及超快速自旋回波加或不加脂肪频谱饱和技术成像 (TSE±SPIRT2WI) .扫描方位包括与视神经平行轴位、斜矢状位及与视神经长轴垂直冠状位和标准冠状位 .结果 视神经眶内段、管内段及视束粗细均匀 .SET1WI显示视神经较周围的蛛网膜下腔信号强度稍高 ,T2WI显示视神经呈相对低信号 ,与脑髓质信号相等 ,周围包绕高信号脑脊液 .与视神经长轴平行的轴位及斜矢状位T1WI及T2WI均可显示视神经全貌 ,与视神经长轴垂直冠状位TSE +SPIRT2WI技术显示视神经信号均匀 .结论 MRI可以较好地显示视神经解剖 ,与视神经长轴垂直冠状位TSE +SPIRT2WI可以较好地显示信号特征 .

Objective To evaluate MRI methods of optic nerve and the findings of normal optic nerve on MRI. Methods Normal optic nerves in 40 cases were studied with Philips ACS-NT15 1.5T MR system and head quadrature coil. The sequences included T1-weighted imaging (T1WI) of spin echo and Turbo spin echo T2-weighted imaging (TSE T2WI) with or without SPIR (Spectral Presatuation with Inversion Recovery). The axial sections and the sagittal sections parallel to optic nerve, and the coronal sections perpendicular to optic nerve were obtained. Results Optic nerves with even dimension from orbital end to optic tracts could be showed on MRI. Compared to CSF, optic nerves appeared as hyperintense signal on SE T1WI and hypointense signal on TSE with or without SPIR T2WI. The signal intensity of normal optic nerves was similar to that of the white matter on SE T1WI and TSE T2WI. The homogeneous signal of optic nerves was showed on TSE SPIR T2WI at the coronal sections perpendicular to optic nerve. The anatomy of the whole optic nerves was showed on axial section and sagittal section parallel to optic nerve on SE T1WI and TSE T2WI. Conclusions Optic nerves could be showed on MRI and the signal of it could be showed better on TSE+SPIR T2WI at coronal section perpendicular to optic nerve.