Table 3.

Comparison of features between patients of MS-associated SSM and NMOSD-associated SSM.

	NMOSD-associated SSM (n = 12)	MS-associated SSM (n = 11)	p value
Age of onset, years, Median (range)	58 (43–79)	30 (22–49)	<0.001
Female-to-male ratio	2:1	5:6	0.414
Interval symptom onset to MRI, days, Median (range)	15 (3–28)	18 (7–30)	0.211
EDSS score at nadir of first attack, Median (range)	2 (1–7.5)	2 (1–4)	0.928
Serum AQP4-IgG, no. (%)	12/12 (100%)	0/11 (0%)	<0.001
CSF white cell count (/μl), Median (range)	5.5 (2–30)	4 (0–8)	0.203
CSF protein (mg/dl), Median (range)	34.8 (19.2–51.5)	28.7 (25.5–56.2)	0.180
CSF oligoclonal bands, no. (%)	0 /7 (0%)	7/10 (70%)	0.010
Serological positive of autoimmune antibodies, no. (%)	9/12 (75%)	3/11 (27%)	0.039
Co-existing systemic autoimmune disease, no. (%)	1/12 (8%)	0/11 (0%)	1.000
Multifocal lesions, no. (%)	2/12 (17%)	5/11 (45%)	0.193
Lesions spanned ⩾2 vertebral segments,* no. (%)	10/12 (83%)	3/11 (27%)	0.012
T1WI hypointensity, no. (%)	1/12 (8%)	1/11 (9%)	1.000
Axial imaging$
Centrally located, no. (%)	10/12 (83%)	3/11 (27%)	0.012
Transversally extensive lesions, no. (%)	10/12 (83%)	4/11 (36%)	0.036
Grey matter involved, no. (%)	12/12 (100%)	6/11 (55%)	0.014
Grey matter, lateral columns and dorsal columns involved simultaneously, no. (%)	10/12 (83%)	5/11 (45%)	0.089
Enhancement on T1WI post-gadolinium images, no. (%)	7/12 (58%)	5/11 (45%)	0.684
Bright spotty lesions, no. (%)	4/12 (33%)	0/11 (0%)	0.093

AQP4-IgG, aquaporin-4 immunoglobulin G; CSF, cerebrospinal fluid; EDSS, Expanded Disability Status Scale; MS, multiple sclerosis; NMOSD, neuromyelitis optica spectrum disorder; SSM, short segment myelitis; T1WI, T1-weighted imaging

^*If the patient had more than 1 lesion, we only analysed the image of the longest one.

^$If more than one axial image of the same patient was available, we analysed the axial plane with the largest lesion.