Analysis of choroidal vessel density in patients with multiple sclerosis

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. To quantify the vascular density (VD) of the choroid (CH) and choriocapillaris (CC) in patients with MS, comparing with normal eyes. 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. 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. 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.