title: Optical coherence tomography segmentation analysis in relapsing remitting versus progressive multiple sclerosis.
abstract: BACKGROUND
  Optical coherence tomography (OCT) with retinal segmentation analysis is a valuable tool in assessing axonal loss and neuro-degeneration in multiple sclerosis (MS) by in-vivo imaging, delineation and quantification of retinal layers. There is evidence of deep retinal involvement in MS beyond the inner retinal layers. The ultra-structural retinal changes in MS in different MS phenotypes can reflect differences in the pathophysiologic mechanisms. There is limited data on the pattern of deeper retinal layer involvement in progressive MS (PMS) versus relapsing remitting MS (RRMS). We have compared the OCT segmentation analysis in patients with relapsing-remitting MS and progressive MS.
  
  
  METHODS
  Cross-sectional study of 113 MS patients (226 eyes) (29 PMS, 84 RRMS) and 38 healthy controls (72 eyes). Spectral domain OCT (SDOCT) using the macular cube acquisition protocol (Cirrus HDOCT 5000; Carl Zeiss Meditec) and segmentation of the retinal layers for quantifying the thicknesses of the retinal layers. Segmentation of the retinal layers was carried out utilizing Orion software (Voxeleron, USA) for quantifying the thicknesses of individual retinal layers.
  
  
  RESULTS
  The retinal nerve finer layer (RNFL) (p = 0.023), the ganglion-cell/inner plexiform layer (GCIPL) (p = 0.006) and the outer plexiform layer (OPL) (p = 0.033) were significantly thinner in PMS compared to RRMS. There was significant negative correlation between the outer nuclear layer (ONL) and EDSS (r = -0.554, p = 0.02) in PMS patients. In RRMS patients with prior optic neuritis, the GCIPL correlated negatively (r = -0.317; p = 0.046), while the photoreceptor layer (PR) correlated positively with EDSS (r = 0.478; p = 0.003).
  
  
  CONCLUSIONS
  Patients with PMS exhibit more atrophy of both the inner and outer retinal layers than RRMS. The ONL in PMS and the GCIPL and PR in RRMS can serve as potential surrogate of disease burden and progression (EDSS). The specific retinal layer predilection and its correlation with disability may reflect different pathophysiologic mechanisms and various stages of progression in MS.
authors.affiliation: Al-Bahar Ophthalmology Center, Ibn Sina Hospital, Kuwait City, Kuwait.|Neurology Clinic, Dasman Institute, Dasman, Kuwait.
authors.forename: Raed
authors.initials: R
authors.lastname: Behbehani
authors.affiliation: Al-Bahar Ophthalmology Center, Ibn Sina Hospital, Kuwait City, Kuwait.
authors.forename: Abdullah
authors.initials: A
authors.lastname: Abu Al-Hassan
authors.affiliation: Al-Bahar Ophthalmology Center, Ibn Sina Hospital, Kuwait City, Kuwait.
authors.forename: Ali
authors.initials: A
authors.lastname: Al-Salahat
authors.affiliation: National Dasman Diabetes Biobank, Dasman Institute, Dasman, Kuwait.
authors.forename: Devarajan
authors.initials: D
authors.lastname: Sriraman
authors.affiliation: Voxeleron LLC, Pleasanton, CA, United States of America.
authors.forename: J D
authors.initials: JD
authors.lastname: Oakley
authors.affiliation: Neurology Clinic, Dasman Institute, Dasman, Kuwait.|Division of Neurology, Amiri Hospital, Sharq, Kuwait.
authors.forename: Raed
authors.initials: R
authors.lastname: Alroughani
mesh_terms: D000293:Adolescent; D000328:Adult; D001284:Atrophy / Q000000981:diagnostic imaging / Q000503:physiopathology; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000000981:diagnostic imaging* / Q000503:physiopathology; D009902:Optic Neuritis / Q000000981:diagnostic imaging / Q000503:physiopathology; D015203:Reproducibility of Results; D012160:Retina / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D012165:Retinal Ganglion Cells / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult