联合应用磁共振弥散张量成像及质子密度加权成像对青光眼患者中枢神经系统视路的初步研究

Combined with diffusion tensor imaging and proton density-weighted magnetic resonance imaging on the visual pathway of central nervous system in patients with glaucoma

目的 使用磁共振成像观察伴双侧视野缺损的青光眼患者眼外中枢神经系统视路的改变。方法 前瞻性研究。35名受检者纳入研究。其中，经眼科检查确诊伴双侧视野缺损的原发性慢性闭角型青光眼患者7例；伴双侧视野缺损的原发性开角型青光眼患者12例；正常对照者16人。采用GE Signa HD 1.5 T超导磁共振扫描仪及头部8通道相控阵头线圈进行扫描；应用弥散张量成像技术测量视路白质纤维束的部分各向异性（FA）及平均扩散系数（DCavg），并行纤维跟踪技术重建白质纤维束；应用冠状位质子密度加权成像技术测量外侧膝状体体积。由两位技术娴熟的神经放射学医生手工描绘感兴趣区，测量双侧视神经、视交叉、双侧视束、双侧视放射的平均FA值、平均DCavg值及双侧外侧膝状体体积。使用SPSS 13.0软件进行统计学分析。结果 不同组间双侧视神经、视交叉、双侧视束、双侧视放射比较，平均FA值差异有统计学意义（F=25.985，20.626，12.262，22.399，21.708，24.994，22.774；P＜0.05），而平均DCavg值差异无统计学意义（F=2.097，2.178，0.530，0.983，0.608，0.866，1.504；P＞0.05）；不同组间外侧膝状体体积比较，差异有统计学意义（F=18.631，17.274；P＜0.05）。结论 青光眼患者存在眼外中枢神经系统视路的变性。

Objective To observe the changes of visual pathway of central nervous system in patients with glaucoma.Methods Thirty-five subjects were enrolled in this prospective study. There were seven patients of chronic primary angle closure glaucoma with bilateral visual field defects, 12 patients of primary open angle glaucoma with bilateral visual field defects, and 16 normal subjects. GE Signa HD 1.5 T magnetic resonance scanners and head eight phased array were used. The mean fractional anisotropy （FA） and the mean average diffusion coefficient （DCavg） of white matter tracts in visual pathway of bilateral optic nerve, optic chiasma, bilateral optic tract,bilateral optic radiation were measured by diffusion tensor imaging, meanwhile the white matter tracts were reconstructed by fiber tracking system. The volumes of lateral geniculate body were measured by coronal proton density weighted magnetic resonance imaging.Results The differences of FA among bilateral optic nerve, optic chiasma, bilateral optic tract,bilateral optic radiation were statistically significant （F=25.985,20.626,12.262,22.399,21.708,24.994,22.774;P〈0.05）. There was no difference of DCavg among bilateral optic nerve, optic chiasma, bilateral optic tract,bilateral optic radiation（F=2.097,2.178,0.530,0.983,0.608, 0.866, 1.504;P〉0.05）. The differences of volume of lateral geniculate body among three groups were statistically significant （F=18.631,17.274;P〈0.05）. Conclusion There is degeneration in visual pathway of central nervous system in patients with glaucoma.