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Sequential phases of RGC axonal and somatic injury in EAE mice examined using DTI and OCT
摘要： Background: Clinical imaging modalities including optical coherence tomography (OCT) and di?usion tensor imaging (DTI) are vital in Multiple Sclerosis (MS), but their relationships during the di?erent phases of Retinal ganglion cell (RGC) degeneration are not clear. We hypothesize that initial injury in optic nerve causes axonal degeneration leading to RGC loss in retina, which can be characterized by a combination of DTI and OCT. Our objective was to examine the correlation between noninvasive and histological data to chronicle the degeneration pro?le of RGCs in the retina and optic nerve in a mouse model of MS. Materials and methods: Experimental Autoimmune Encephalomyelitis (EAE) was induced in 11 C57Bl/6 mice, with 8 mice reserved as controls. OCT and DTI was conducted 2–8 weeks after induction of EAE. The thickness of the retinal ganglion cell complex (GCC) was measured using OCT and compared to DTI indices measured in optic nerves. End-stage histology was used to quantify axon/myelin loss in the optic nerve and retinal thinning/RGC loss in the retina. Results: Signi?cant changes in DTI-derived Axial Di?usivity (AD, ?17.2%) and Trace Di?usivity (TR, ?18.3%) began after 2 weeks of EAE. Later signi?cant reductions in Fractional Anisotropy (FA) and AD, with increases in Radial Di?usion (RD) were apparent after 4 and 8 weeks. OCT-derived measures of GCC thickness were reduced after 4 weeks, and reached signi?cant reduction after 8 weeks. Among EAE mice, DTI (FA, AD and RD measures) and OCT measures were all signi?cantly correlated after 4 and 8 weeks. Among histology measures, RGC density (?23%), RGC size (?27%), and the number of SMI31+ axons (?54%) were reduced signi?cantly. DTI measures of FA and AD along with GCC thinning were the best independent predictors of axon loss. Conclusions: DTI and OCT measures are tightly correlated during the chronic phase of axonal degeneration (4–8 weeks) in EAE mice. After 8 weeks of EAE, both OCT and DTI measures are strong predictors of axon loss in the Optic Nerve.
关键词： longitudinal study,Optical coherence tomography (OCT),Retinal ganglion cell (RGC),Experimental Autoimmune Encephalomyelitis (EAE),Di?usion tensor imaging (DTI)
更新于2025-09-10 09:29:36
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Evaluation of Structure-Function Relationships in Longitudinal Changes of Glaucoma using the Spectralis OCT Follow-Up Mode
摘要： The detection of glaucoma progression is an essential part of glaucoma management. Subjectivity of standard automated perimetry (SAP) prevents the accurate evaluation of progression, thus the detection of structural changes by optical coherence tomography (OCT) is attracting attention. Despite its objectivity, there is controversy about the appropriateness of the use of OCT, because many previous studies have indicated OCT results may not reflect the deterioration of visual field. A reason for this dissociation may be the test-retest variability of OCT, a major cause of which is misplacement of the measurement location. Recent advantages of spectral-domain OCT (SD-OCT), especially Spectralis OCT with an eye-tracking system (follow-up mode) enable measurement at approximately the same location as previous examinations. In addition to utilizing Spectralis follow-up mode, we introduced structure-function relationship map and nonlinear relationship between SAP and OCT results in considering structure-function relationship in longitudinal changes. The introduction of these two ideas in our study population improved the correlation between the SAP and OCT (R = 0.589 at most). The results of this study support the practical use of OCT in glaucoma progression but also stress the importance of focus on the corresponding focal changes and the consideration of disease severity.
关键词： longitudinal study,standard automated perimetry,optical coherence tomography,structure-function relationship,glaucoma progression
更新于2025-09-10 09:29:36