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Investigating Tissue Optical Properties and Texture Descriptors of the Retina in Patients with Multiple Sclerosis.

Varga BE, Gao W, Laurik KL, Tátrai E, Simó M, Somfai GM, Cabrera DeBuc D - PLoS ONE (2015)

Bottom Line: Significant difference was found in contrast in the RNFL, GCL+IPL, GCC, inner nuclear layer (INL) and outer plexiform layer when comparing MSON+ to the other groups.A significant difference was found in layer index in the RNFL, GCL+IPL and GCC layers in all comparisons.Our results may help to further improve the diagnostic efficacy of OCT in MS and neurodegeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.

ABSTRACT

Purpose: To assess the differences in texture descriptors and optical properties of retinal tissue layers in patients with multiple sclerosis (MS) and to evaluate their usefulness in the detection of neurodegenerative changes using optical coherence tomography (OCT) image segmentation.

Patients and methods: 38 patients with MS were examined using Stratus OCT. The raw macular OCT data were exported and processed using OCTRIMA software. The enrolled eyes were divided into two groups, based on the presence of optic neuritis (ON) in the history (MSON+ group, n = 36 and MSON- group, n = 31). Data of 29 eyes of 24 healthy subjects (H) were used as controls. A total of seven intraretinal layers were segmented and thickness as well as optical parameters such as contrast, fractal dimension, layer index and total reflectance were measured. Mixed-model ANOVA analysis was used for statistical comparisons.

Results: Significant thinning of the retinal nerve fiber layer (RNFL), ganglion cell/inner plexiform layer complex (GCL+IPL) and ganglion cell complex (GCC, RNFL+GCL+IPL) was observed between study groups in all comparisons. Significant difference was found in contrast in the RNFL, GCL+IPL, GCC, inner nuclear layer (INL) and outer plexiform layer when comparing MSON+ to the other groups. Higher fractal dimension values were observed in GCL+IPL and INL layers when comparing H vs. MSON+ groups. A significant difference was found in layer index in the RNFL, GCL+IPL and GCC layers in all comparisons. A significant difference was observed in total reflectance in the RNFL, GCL+IPL and GCC layers between the three examination groups.

Conclusion: Texture and optical properties of the retinal tissue undergo pronounced changes in MS even without optic neuritis. Our results may help to further improve the diagnostic efficacy of OCT in MS and neurodegeneration.

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Related in: MedlinePlus

Retinal scanning and macular regions used in the study.(A) The fundus image of a healthy eye. The white arrows in the macula show the locations of the OCT scans made. (B) The distribution of macular regions: foveolar region (a) with the diameter of 0.375 mm, foveal region (b) with a diameter of 1.85 mm; parafoveal region (c) with a diameter of 2.85 mm and perifoveal region (d) with a diameter of 5.85 mm.
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pone.0143711.g002: Retinal scanning and macular regions used in the study.(A) The fundus image of a healthy eye. The white arrows in the macula show the locations of the OCT scans made. (B) The distribution of macular regions: foveolar region (a) with the diameter of 0.375 mm, foveal region (b) with a diameter of 1.85 mm; parafoveal region (c) with a diameter of 2.85 mm and perifoveal region (d) with a diameter of 5.85 mm.

Mentions: It is worth to note that before the calculation of parameters related to reflectance values, the lateral coordinates of the blood vessel shadows were obtained by the help of a blood vessel shadowgram technique and were removed in each OCT image. [35] Following this, these shadows were removed in each OCT image before calculating the values for reflectance. Total reflectance values included average values of reflectance with normalization to the RPE reflectance (NRPE). Average values of total reflectance per intraretinal layer were calculated. Total reflectance values were converted to decibels (dB = 10 ×log10 [TR]). Layer index parameter was based on the mean reflectance corrected to the thickness of the region of interest and the 99% of the total reflectance of the scan (see details above and Eq 5). [18] All calculated values were expressed in the foveolar, foveal, parafoveal and perifoveal regions and also as a mean across all macular regions. (Fig 2.) In the foveolar region, the calculations were limited to the outer retinal layers (OPL+IS, OS, RPE). For the analyses an additional composite layer was defined, the GCC consisting of the RNFL and GCL+IPL layers with the purpose to observe the changes of the whole ganglion cell with its proximal and distal denrites.


Investigating Tissue Optical Properties and Texture Descriptors of the Retina in Patients with Multiple Sclerosis.

Varga BE, Gao W, Laurik KL, Tátrai E, Simó M, Somfai GM, Cabrera DeBuc D - PLoS ONE (2015)

Retinal scanning and macular regions used in the study.(A) The fundus image of a healthy eye. The white arrows in the macula show the locations of the OCT scans made. (B) The distribution of macular regions: foveolar region (a) with the diameter of 0.375 mm, foveal region (b) with a diameter of 1.85 mm; parafoveal region (c) with a diameter of 2.85 mm and perifoveal region (d) with a diameter of 5.85 mm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4664388&req=5

pone.0143711.g002: Retinal scanning and macular regions used in the study.(A) The fundus image of a healthy eye. The white arrows in the macula show the locations of the OCT scans made. (B) The distribution of macular regions: foveolar region (a) with the diameter of 0.375 mm, foveal region (b) with a diameter of 1.85 mm; parafoveal region (c) with a diameter of 2.85 mm and perifoveal region (d) with a diameter of 5.85 mm.
Mentions: It is worth to note that before the calculation of parameters related to reflectance values, the lateral coordinates of the blood vessel shadows were obtained by the help of a blood vessel shadowgram technique and were removed in each OCT image. [35] Following this, these shadows were removed in each OCT image before calculating the values for reflectance. Total reflectance values included average values of reflectance with normalization to the RPE reflectance (NRPE). Average values of total reflectance per intraretinal layer were calculated. Total reflectance values were converted to decibels (dB = 10 ×log10 [TR]). Layer index parameter was based on the mean reflectance corrected to the thickness of the region of interest and the 99% of the total reflectance of the scan (see details above and Eq 5). [18] All calculated values were expressed in the foveolar, foveal, parafoveal and perifoveal regions and also as a mean across all macular regions. (Fig 2.) In the foveolar region, the calculations were limited to the outer retinal layers (OPL+IS, OS, RPE). For the analyses an additional composite layer was defined, the GCC consisting of the RNFL and GCL+IPL layers with the purpose to observe the changes of the whole ganglion cell with its proximal and distal denrites.

Bottom Line: Significant difference was found in contrast in the RNFL, GCL+IPL, GCC, inner nuclear layer (INL) and outer plexiform layer when comparing MSON+ to the other groups.A significant difference was found in layer index in the RNFL, GCL+IPL and GCC layers in all comparisons.Our results may help to further improve the diagnostic efficacy of OCT in MS and neurodegeneration.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.

ABSTRACT

Purpose: To assess the differences in texture descriptors and optical properties of retinal tissue layers in patients with multiple sclerosis (MS) and to evaluate their usefulness in the detection of neurodegenerative changes using optical coherence tomography (OCT) image segmentation.

Patients and methods: 38 patients with MS were examined using Stratus OCT. The raw macular OCT data were exported and processed using OCTRIMA software. The enrolled eyes were divided into two groups, based on the presence of optic neuritis (ON) in the history (MSON+ group, n = 36 and MSON- group, n = 31). Data of 29 eyes of 24 healthy subjects (H) were used as controls. A total of seven intraretinal layers were segmented and thickness as well as optical parameters such as contrast, fractal dimension, layer index and total reflectance were measured. Mixed-model ANOVA analysis was used for statistical comparisons.

Results: Significant thinning of the retinal nerve fiber layer (RNFL), ganglion cell/inner plexiform layer complex (GCL+IPL) and ganglion cell complex (GCC, RNFL+GCL+IPL) was observed between study groups in all comparisons. Significant difference was found in contrast in the RNFL, GCL+IPL, GCC, inner nuclear layer (INL) and outer plexiform layer when comparing MSON+ to the other groups. Higher fractal dimension values were observed in GCL+IPL and INL layers when comparing H vs. MSON+ groups. A significant difference was found in layer index in the RNFL, GCL+IPL and GCC layers in all comparisons. A significant difference was observed in total reflectance in the RNFL, GCL+IPL and GCC layers between the three examination groups.

Conclusion: Texture and optical properties of the retinal tissue undergo pronounced changes in MS even without optic neuritis. Our results may help to further improve the diagnostic efficacy of OCT in MS and neurodegeneration.

Show MeSH
Related in: MedlinePlus