Optical coherence tomography angiography helps distinguish multiple sclerosis from AQP4‐IgG‐seropositive neuromyelitis optica spectrum disorder

INTRODUCTION: The aim was to characterize the optical coherence tomography (OCT) angiography measures in patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) and to evaluate their disease discrimination capacity. METHODS: Patients with MS (n = 83) and AQP4‐IgG‐seropositive NMOSD (n = 91) with or without a history of optic neuritis, together with healthy controls (n = 34), were imaged. The main outcome measures were peripapillary retinal nerve fiber layer (pRNFL) thickness, macular ganglion cell‐inner plexiform layer (GC‐IPL) thickness, macular vessel density (VD), and perfusion density (PD) in the superficial capillary plexus. Diagnostic accuracy was assessed using the area under the receiver operating characteristics curve. RESULTS: Compared with patients with MS, those with NMOSD had a significantly smaller average thickness of the pRNFL and GC‐IPL (80.0 [59.0; 95.8] μm versus 92.0 [80.2; 101] μm, p < .001; 68.0 [56.0; 81.0] μm, versus 74.5 [64.2; 81.0] μm, p < .001) and significantly smaller whole VD and PD areas (15.6 [12.6; 17.0] mm(−1) versus 16.7 [14.8; 17.7] mm(−1), p < .001; 0.38 [0.31; 0.42] mm(−1) versus 0.40 [0.37; 0.43] mm(−1), p < .01). The combination of structural parameters (average thickness of the pRNFL and GC‐IPL) with microvascular parameters (temporal‐inner quadrant of VD, temporal‐inner, nasal‐inferior, and nasal‐outer quadrant of PD) was revealed to have a good diagnostic capability for discriminating between NMOSD and MS. CONCLUSIONS: OCT angiography reveals different structural and microvascular retinal changes in MS and AQP4‐IgG‐seropositive NMOSD. These combined structural and microvascular parameters might be promising biomarkers for disease diagnosis.