Analysis of choroidal vessel density in patients with multiple sclerosis

Introduction: Multiple Sclerosis (MS) is a chronic neuro inflammatory disease which leads to progressive disability. Recent evidence suggests that vascular impairment may contribute to MS onset and progression. Optical Coherence Tomography Angiography (OCT-A) has emerged as an important imaging tool which should allow further exploration of the vessel changes in the pathogenesis and prognosis of MS. Purpose: To quantify the vascular density (VD) of the choroid (CH) and choriocapillaris (CC) in patients with MS, comparing with normal eyes. Materials and Methods: 45 eyes of 45 MS patients [31 female; mean age (years ± SD) 41,87 ± 11.04; axial length (AL) (AL ± SD) 23.68 ± 0.90) and 45 aged-matched control subjects (33 female; mean age 39,.6 ± 8,93; AL 23.36 ± 0.75] were enrolled in this prospective study. We obtained OCT-A images based on a full-spectrum amplitude de-correlation angiography (FSADA) algorithm. The OCT-A images of the CH and CC were used for quantitative assessment in three regions of the fovea, namely, Region 1 (0–500 μm) Region 2 (500–1000 μm) and Region 3 (1000−1500 μm). Relationships of VD between MS patients with and without optic neuritis (ON) and controls were investigated by binary vessel maps generated from OCT-A slabs and analyzed using ImageJ software. Results: Compared to controls, in eyes with MS, CH VD was significantly decreased in Region 2 (p = 0.01) and Region 3 (p < 0.01). CCVD was not different between the groups although showing a decreasing tendency in the MS group. Between eyes with and without ON there were a tendency to reduced VD in the ON group in all regions analyzed for both CH and CC layer. All the layers analyzed revealed a positive correlation between CH VD and CC VD and a negative correlation between CC VD and AL. Conclusions: Although studies have assessed retinal VD in MS using OCT-A, the choroidal vasculature in MS remains understudied. Our results cautiously suggest a functional circulatory disturbance of choroidal vasculatures in MS patients, mainly in those who have previous ON history