Garaci Francesco G, Bolacchi Francesca, Cerulli Angelica, Melis Milena, Spanò Arnoldo, Cedrone Claudio, Floris Roberto, Simonetti Giovanni, Nucci Carlo
Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University Hospital Tor Vergata, Viale Oxford 81, 00133 Rome, Italy.
Radiology. 2009 Aug;252(2):496-501. doi: 10.1148/radiol.2522081240. Epub 2009 May 12.
To evaluate, with high-field-strength diffusion-tensor (DT) magnetic resonance (MR) imaging, the axonal architecture of the optic nerves and optic radiations in patients with glaucoma and determine whether DT MR imaging-derived parameters correlate with disease severity.
The study was approved by the institutional review board. All participants provided written informed consent. Sixteen patients with primary open-angle glaucoma were examined. Glaucoma severity was clinically assessed with use of a six-stage system based on static threshold visual field parameters. Ten healthy individuals served as control subjects. DT MR imaging was performed with a 3-T MR unit. Mean diffusivity (MD) and fractional anisotropy (FA) maps were automatically created. Regions of interest were positioned on the MD and FA maps, and mean MD and mean FA values were calculated for each optic nerve and each optic radiation.
The optic radiations and optic nerves of patients with glaucoma, as compared with control subjects, had significantly higher MD and significantly lower FA. The mean MD values for the optic nerves and the glaucoma stages varied consistently (r = 0.8087, P < .0001). A negative correlation between mean FA for the optic nerves and glaucoma stage (r = -0.7464, P < .0001) was observed.
Glaucoma is a complex neurologic disease that affects optic nerves and optic radiations. The finding that DT MR imaging-derived MD and FA in the optic nerves correlate with glaucoma severity suggests that these parameters could serve as complementary indicators of disease severity.
采用高场强扩散张量（DT）磁共振（MR）成像评估青光眼患者视神经和视辐射的轴突结构，并确定DT MR成像得出的参数是否与疾病严重程度相关。
本研究经机构审查委员会批准。所有参与者均提供了书面知情同意书。对16例原发性开角型青光眼患者进行了检查。基于静态阈值视野参数，采用六级系统对青光眼严重程度进行临床评估。10名健康个体作为对照。使用3-T MR设备进行DT MR成像。自动生成平均扩散率（MD）和分数各向异性（FA）图。在MD和FA图上放置感兴趣区域，并计算每条视神经和每个视辐射的平均MD和平均FA值。
与对照组相比，青光眼患者的视辐射和视神经的MD显著更高，FA显著更低。视神经的平均MD值与青光眼分期一致变化（r = 0.8087，P <.0001）。观察到视神经的平均FA与青光眼分期之间呈负相关（r = -0.7464，P <.0001）。
青光眼是一种影响视神经和视辐射的复杂神经疾病。视神经中DT MR成像得出的MD和FA与青光眼严重程度相关这一发现表明，这些参数可作为疾病严重程度的补充指标。
