Table 2.

Clinical characteristics at MRI-2 and brain volumes in patients with AQP4 + NMOSD and HCs.

	AQP4 + NMOSD (N = 29)	HCs (N = 29)	P-value
Years from last attack to MRI-2	5.2 [6.3] (0.9–10.3)
Years of relapse prevention treatment	3.3 [4.4] (0.8–7.9)
ΔEDSS (MRI-2 – MRI-1)	0.0 [− 0.5] (− 2.0–3.5)
Years from MRI-1 to MRI-2	3.2 [2.3] (1.0–6.3)	2.9 [1.1] (1.0–3.0)	0.009*
ARR between MRI-1 and MRI-2	0.0 [0.1] (0.0–0.9)
At MRI-1
ICV*10–3 (mL)	1.35 [0.14] (1.22–1.60)	1.37 [0.21] (1.18–1.86)	0.40
NLV (mL)	0.96 [4.08] (0.00–16.30)
NGV*10–3 (mL)	0.42 [0.05] (0.32–0.49)	0.45 [0.04] (0.37–0.52)	0.004*
NWV*10–3 (mL)	0.30 [0.03] (0.26–0.34)	0.29 [0.03] (0.26–0.34)	0.17
NBV*10–3 (mL)	0.73 [0.06] (0.62–0.81)	0.75 [0.04] (0.66–0.85)	0.044*
At MRI-2
ICV*10–3 (mL)	1.35 [0.13] (1.21–1.58)	1.37 [0.21] (1.18–1.86)	0.37
NLV (mL)	1.70 [7.15] (0.00–141.5)
NGV*10–3 (mL)	0.41 [0.06] (0.31–0.49)	0.44 [0.04] (0.37–0.51)	0.008*
NWV*10–3 (mL)	0.30 [0.03] (0.24–0.34)	0.30 [0.03] (0.26–0.34)	0.32
NBV*10–3 (mL)	0.73 [0.08] (0.59–0.80)	0.74 [0.05] (0.66–0.83)	0.069
Annualized atrophy rate
NGV (%)	0.44 [0.15] (− 2.44–4.88)	0.71 [1.24] (− 1.43–3.14)	0.43
NWV (%)	0.37 [1.36] (− 6.23–4.48)	− 0.14 [0.92] (− 1.76–1.03)	0.018*
NBV (%)	0.50 [0.75] (− 0.57–3.04)	0.41 [0.75] (− 0.88–1.72)	0.91

Data are presented as median number (%) or [interquartile range] (range). *P < 0.05.

ΔEDSS = EDSS at MRI-2 minus EDSS at MRI-1. Years of the relapse prevention treatment indicate the continuous relapse prevention treatment period at the same dosage which was given at MRI-2.

AQP4 + NMOSD anti-aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder disease, ARR annual relapse rate, EDSS Kurtzke’s Expanded Disability Status Scale, ICV intracranial volume, NBV normalized brain volume, NGV normalized gray matter volume, NLV normalized lesion volume, NWV normalized white matter volume. Annualized atrophy rate of X is defined as follows; $\frac{\left(\text{X}\text{at}\text{1st}\text{MRI}\text{scan}\times \text{at}\text{2nd}\text{MRI}\text{scan}\right)\times 12}{\left(\text{X}\text{at}\text{1st}\text{MRI}\text{scan}\right)\times \left(\text{Months}\text{between}\text{1st}\text{and}\text{2nd}\text{MRI}\text{scans}\right)}$ , X = NGV, NWV or NBV.