Association Between Clinical And Radiological Features And Optical Coherence Tomography (oct) Measures In Multiple Sclerosis (ms)

Abstract

Purpose: : MS causes relentless degeneration of the central nervous system, represented by diffuse axonal (neuronal) loss. This process can be assessed in-vivo by retinal fiber layer thickness (RNFLt) measurement by OCT. This technique is a potential biomarker in MS; however, more studies are needed to support this role. We describe the correlation between OCT measures and clinically and radiologically relevant variables in MS.

Methods: : 66 MS patients and 26 age-sex matched healthy controls were studied. Expanded Disability Status Scale (EDSS) was assessed in all patients. Ophthalmic examination included visual acuity and contrast sensitivity (ETDRS and SLOAN, respectively), color vision (HRR pseudoisochromatic plates), automated visual field, slit lamp and fundus examination. RNFLt in peripapillar cardinal sectors and macular volume (MV) were measured by spectral domain OCT. Ophthalmic and OCT variables were analyzed as mean values of both eyes, except in ON-patients in which both eyes were analyzed independently. Total brain, white and grey matter volumes were obtained from T1MPRAGE sequence on a 3T MRI in 40 patients.

Results: : The median age of patients was 41 years (19 - 61 years), 48 were female (73%), the median MS duration was 6.3 years (7 months - 28.8 years), 27 of them (41%) had past history of acute optic neuritis (ON). RNFLt was statistically lower in patients comparing to controls (p< 0.001); it was also lower in ON patients comparing to non-ON patients (p < 0.01). Negative correlation was observed between the duration of the disease and RNFLt, especially in non-ON cases (global RNFLt: p: 0.03, r: -0.399). EDSS correlated to papillomacular bundle (PMB) thickness only in no-ON patients (p: 0.04, r: -0.385). RNFLt also correlated to ETDRS (p: 0.004, r: 0.4) and especially to HRR (p: <0.001, r: 0.49), which also correlated to the MV (p: 0.01, r: 0.362). SLOAN test did not correlate with OCT findings. Temporal and PMB RNFLt correlated strongly with all volumetric brain measurements except for the lesion burden.

Conclusions: : These results support previous studies favoring RNFLt as a correlate to clinically relevant measures in MS. In line with previous data, HRR may be a strong functional tool to assess RNFLt in MS; however, SLOAN test did not show the same results. Larger and prospective studies are warranted to proof the role of OCT as a solid biomarker in MS.

Keywords: nerve fiber layer • visual impairment: neuro-ophthalmological disease • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)