To describe and identify the overlapping and distinguishing neuroimaging features among MS, NMOSD, and MOGAD syndromes.

In the era of the enlarging spectrum of MS and other antibody-associated demyelinating syndromes, there remain some cases with overlapping neuroimaging features that cause diagnostic and therapeutic challenges. In this context, the main diagnostic marker is the serological status of the patients. To fill this diagnostic gap, further research is warranted for better distinguishing neuroimaging markers in the lack of antibody testing.

A total of 204 MS patients fulfilling the McDonald 2017 criteria, 36 AQP4-IgG+ and 21 double-seronegative NMOSD patients fulfilling the 2015 diagnostic criteria for NMOSD, and 15 MOGAD patients fulfilling the 2023 MOGAD Panel proposed criteria were included. Demographic features and neuroimaging findings of the four groups were retrospectively evaluated.

Female ratios were 69.6% in the MS, 94.4% in the AQP4+NMOSD, 76.2% in the seronegative NMOSD, and 33.3% in the MOGAD groups. Temporal periventricular lesions were significantly higher in the MOGAD group than in the AQP4-IgG+ and seronegative NMOSD groups (p=0.02 for both). Cerebellar peduncle lesions were significantly higher in the MOGAD group compared with the AQP4-IgG+ NMOSD group (p=0.07). Longitudinally-extensive spinal cord lesions were significantly higher in AQP4-IgG+ and seronegative NMOSD groups than in the MOGAD group (p=0.01 and p=0.001, respectively). There was no statistically significant difference between the proportion of longitudinally-extensive optic neuritis lesions between the NMOSD and MOGAD groups. Spinal atrophy was significantly lower in the MOGAD group compared with the AQP4-IgG+ and seronegative NMOSD groups (p=0.03 and p=0.04, respectively).

Although the diagnostic criteria for MS and NMOSD are available and were also recently proposed for MOGAD, the neuroimaging features of these disorders may be strikingly similar. To overcome this diagnostic uncertainty, overlapping and distinguishing neuroimaging features of CNS disorders should be investigated more thoroughly.