Optic Radiations Microstructural Changes in Glaucoma and Association With Severity: A Study Using 3Tesla-Magnetic Resonance Diffusion Tensor Imaging

Abstract

Citation: Tellouck L, Durieux M, Coupé P, et al. Optic radiations microstructural changes in glaucoma and association with severity: a study using 3Tesla-magnetic resonance diffusion tensor imaging. Invest Ophthalmol Vis Sci. 2016;57:6539-6547. DOI:10.1167/iovs.16-19838 PURPOSE. To compare microstructural changes along the optical radiations and brain structure volumes between glaucoma and control subjects using in vivo magnetic resonance imaging and to analyze their association with severity of the disease. METHODS.A total of 50 open-angle glaucoma subjects and 50 healthy age-and sex-matched controls underwent detailed ophthalmologic examinations (including visual field testing [VF], funduscopy, and spectral-domain optical coherence tomography) as well as diffusion tensor imaging (DTI) using 3.0-Tesla magnetic resonance imaging. Fractional anisotropy (FA), mean diffusivity, radial diffusivity (RD), and axial diffusivity (AD) were quantified semiautomatically along the optical radiations. DTI parameters and volumes of specific brain structures were compared between cases and controls using conditional logistic regression. Association between DTI metrics and the severity of the disease was studied using linear mixed regression analyses. RESULTS.In glaucoma subjects, optic radiations FA was significantly lower (0.57 vs. 0.59; P ¼ 0.02) and RD was significantly higher (52.78 10 -5 mm 2 /s vs. 49.74 10 -5 mm 2 /s; P ¼ 0.03) than in controls. Optic radiations FA was significantly correlated with homolateral functional and structural damage of glaucoma (mean deviation of VF [P ¼ 0.03], retinal nerve fiber layer thickness [P ¼ 0.03], vertical cup to disc ratio [P ¼ 0.0007]). Volume and DTI parameters of other brain structures (including hippocampus) were not significantly different between glaucoma patients and controls.CONCLUSIONS. We evidenced microstructural modifications along visual pathways of glaucoma patients and these alterations were correlated with disease severity. The association of glaucoma with other neurodegenerative alterations would need further exploration and a prospective follow-up of our cohort of subjects. (ClinicalTrials.gov number, NCT01621841).

White Matter Abnormalities and Correlation With Severity in Normal Tension Glaucoma: A Whole Brain Atlas-Based Diffusion Tensor Study

“…[16][17][18] In addition, mean deviation of visual field (MDVF) and retinal nerve fiber layer (RNFL) thickness can be measured by standard automated perimetry and optical coherence tomography Copyright 2018 The Authors iovs.arvojournals.org j ISSN: 1552-5783 (OCT), respectively, with a sensitivity that reflects the degree of glaucoma. 19 Previous studies [20][21][22][23][24][25][26] have demonstrated that DTI parameters of the visual pathway are correlated with MDVF and RNFL thickness via ROI analysis. However, to the best of our knowledge, this is the first study to explore the abnormalities of whole brain WM regions with DTI parameters in NTG patients by using the ABA method, and the correlations between them and MDVF and RNFL thickness.…”

Changes of Visual Pathway and Brain Connectivity in Glaucoma: A Systematic Review

“…Differences of microstructure in white matter structures have been found in the optic nerve, optic tracts, optic chiasm, optic radiations, and occipital lobe. These results were obtained in studies including POAG (Garaci et al, 2009 ; El-Rafei et al, 2011 , 2013 ; Engelhorn et al, 2011 ; Bolacchi et al, 2012 ; Nucci et al, 2012 ; Zhang et al, 2012 ; Zikou et al, 2012 ; Chen Z. et al, 2013 ; Lu et al, 2013 ; Michelson et al, 2013 ; Frezzotti et al, 2014 , 2016 ; Kaushik et al, 2014 ; Omodaka et al, 2014 ; Schoemann et al, 2014 ; Sidek et al, 2014 ; Murai et al, 2015 ; Tellouck et al, 2016 ; Zhou et al, 2017a ; Giorgio et al, 2018 ), NTG (Boucard et al, 2016 ) and PACG (Wang et al, 2013 ) patients.…”

Diagnostic utility of central damage determination in glaucoma by magnetic resonance imaging: An observational study

“…A total of 24 patients with POAG (age, 34.29±10.69 years; males/females, 19/5) and 24 age-and sex-matched non-glaucomatous healthy controls (age, 34.38±11.17 years; males/females, 19/5) were recruited for the present observational study. All of the study subjects underwent comprehensive ophthalmological examinations, including best corrected visual acuity, slit-lamp microscopy and indirect ophthalmoscope examination, intraocular pressure (IOP) measurement, anterior chamber angle examination using gonioscopy, visual field test (Octopus perimeter), central corneal thickness, axial length and retinal nerve fiber layer (RNFL) thickness (Heidelberg spectral domain optical coherence tomography) measurements (5)(6)(7)(8). Subjects were included in the POAG group according to the following selection criteria: i) The subject was ≥18 years of age; ii) a cup-to-disc (C/D) ratio ≥0.6, or an interocular C/D ratio difference of ≥0.2; iii) presence of an RNFL defect; iv) glaucomatous visual field defects corresponding to optic nerve changes and v) normal anterior chamber depth with an open angle.…”

“…Glaucoma is a leading cause of irreversible blindness worldwide (1) and retinal ganglion cell (RGC) degeneration is a major pathogenic characteristic of glaucoma (2,3). Furthermore, a number of magnetic resonance imaging (MRI) studies have reported that glaucomatous damage only affects RGCs in the eyes, but also extends across the central visual pathway, then further affecting the optic tract, lateral geniculate nucleus (LGN) and the optic radiation (4)(5)(6)(7)(8). Using high-resolution 7.0-T MRI, Lee et al (4) identified that the LGN volumes are significantly smaller in primary open-angle glaucoma (POAG) patients compared with those in healthy subjects.…”

“…A similar MRI study by Chen et al (5) confirmed this result and further indicated that the LGN atrophy is consistent with the damage of the optic disc in POAG patients. Besides LGN atrophy, the fractional anisotropy (FA) of POAG patients also exhibited significant alterations, the degree of which was closely correlated with the disease severity, indicating that the atrophy of the visual cortex may be an important diagnostic index for POAG and may be utilized to guide its treatment (6,7). In addition, radiological evidence of neurodegeneration in the optic tract and optic radiation of POAG patients was provided, and this neurodegeneration was associated with the damage of the optic disc and the loss of visual function (8).…”