视神经疾病的En Face相干光断层扫描改变

En face optical coherence tomography abnormalities in optic nerve diseases

目的利用En Face相干光断层扫描(OCT)分析视神经炎、Leber遗传性视神经病变、视盘旁血管瘤、视盘小凹、压迫性视神经病变(垂体瘤)和青光眼的影像学改变。方法采用频域OCT(RTVue-100,Optovue)3D Disc、ONH和GCC扫描模式,En Face分析程序分别在视网膜内界膜(ILM)层面、内丛状层(IPL)层面、神经纤维层面(RNFL)、色素上皮(RPE)层面和色素上皮参考层面观察以上视神经疾病的En Face OCT改变。结果视神经炎伴视盘水肿的En Face OCT在ILM层面可见水肿的边界,在RNFL层面可见水肿的神经纤维排列分布,在RPE层面可见被水肿遮挡的实际的视盘形态和血管分布;Leber遗传性视神经病变在ILM和RNFL层面均可见视盘颞侧大片扇形低反射区,提示视盘黄斑神经纤维束的丢失,与颞上和颞下RNFL的高反射区形成鲜明对比,黄斑区节细胞联合体的厚度明显变薄;视盘旁血管瘤在RPE和脉络膜层面(色素上皮参考层面)可见瘤体边界;视盘小凹在从ILM到脉络膜的各个层面均可见小凹的边界和结构的变化;垂体瘤压迫所致的视神经病变可见ILM和RNFL层面视盘颞侧和鼻侧大片扇形低反射区,提示经过视交叉神经纤维的丢失,黄斑区节细胞联合体的厚度明显变薄;青光眼在ILM和RNFL界面可见弓形神经纤维束的丢失呈低反射改变,RPE界面见视盘和大视杯清晰的边界。结论 En Face OCT是眼科影像学的一项突破,为视神经疾病影像学的诊断提供新的途径。它能从视神经、视神经周围及黄斑区的各个解剖层面深入了解视神经病变的结构改变以及视交叉压迫所致的退行性改变对视网膜神经节细胞造成的损害,是辅助诊断和评价视神经病变的有力工具。

Objective To observe imaging abnormalities in optic neuritis, Leber hereditary optic neuropathy （LHON）, peripapillary agioma, compressive optic neuropathy and glaucoma using en face optical coherence tomography （OCT）. Methods Scanning protocols of 3D Disc, ONH and GCC on spectral-domain OCT （RTVue-100, Optovue, Fremont, CA） had been used. En Face OCT analysis protocols processed data of the above optic nerve diseases on the reference levels of inner limiting membrane （ILM）, inner plexiform layer （IPL）, retinal nerve fiber layer （RNFL）, retinal pigment epithelial （RPE） and RPE reference. Results In optic neuritis, the border of the disc edema could be outlined at ILM level. The distribution of the swollen nerve fibers could be observed in RNFL level. The actual disc contour and blood vessels which were obscured by disc edema could be seen at RPE level. In LHON, sectorial defect of hyporeflective area at the levels of ILM and RNFL appeared on the temporal sides of both discs meaning the loss of maculo-papillary bundle. The thicknesses of ganglion cell complex （GCC） in the macula were thinner comparing with normals. The boundary of the agioma could be demarcated at RPE reference level in peri-papillary agioma. In optic pit, the border and structural changes of the pit could be observed at each reference level. In compressive optic neuropathy （pituitary adenoma）, sectorial defect of hypo-reflective area at the level of ILM and RNFL appeared on the temporal and nasal sides of discs suggesting nerve fibers loss at the chiasm due to compression of the pituitary adenoma. The thicknesses of GCC were thinner on both eyes. In glaucoma, retinal nerve fiber bundle loss originating from the superior-temporal sector of the disc showed as a hypo-reflective band at ILM and RNFL levels. The cup border could be clearly outlined at the level of RPE. Conclusions En Face OCT is a break-through of ophthalmic imaging technology. The technology reveals the structure of the optic nerve head and its surroundings layer by layer. It helps to better understand the pathology of optic nerve diseases.