Glymphatic System Dysfunction in Myelin Oligodendrocyte Glycoprotein Immunoglobulin G Antibody–Associated Disorders: Association with Clinical Disability
Akifumi Hagiwara, Yuji Tomizawa, Y. Hoshino, Kazumasa Yokoyama, Koji Kamagata, Towa Sekine, Kaito Takabayashi, Moto Nakaya, Tomoko Maekawa, Toshiaki Akashi, Akihiko Wada, Toshiaki Taoka, Shinji Naganawa, Nobutaka Hattori, Shigeki Aoki
Abstract
<h3>BACKGROUND AND PURPOSE:</h3> Impaired glymphatic function has been suggested to be implicated in the pathophysiology of MS and aquaporin-4 immunoglobulin G-positive neuromyelitis optica spectrum disorder. This study aimed to investigate the interstitial fluid dynamics in the brain in patients with myelin oligodendrocyte glycoprotein antibody disorders (MOGAD), another demyelinating disorder, using a noninvasive imaging technique called the diffusivity along the perivascular space (ALPS) index. <h3>MATERIALS AND METHODS:</h3> A prospective study was conducted on 16 patients with MOGAD in remission and 22 age- and sex-matched healthy control subjects. MR imaging was performed using a 3T scanner, and the ALPS index was calculated using diffusion MR imaging data with a b-value of 1000 s/mm<sup>2</sup>. The ALPS index and gray matter volumes were compared between the 2 groups, and these parameters were correlated with the Expanded Disability Status Scale. <h3>RESULTS:</h3> The mean ALPS index of patients with MOGAD was significantly lower than that of healthy controls (Cohen <i>d</i> = 0.93, false discovery rate–corrected <i>P </i>= .02). The lower mean ALPS index was significantly associated with a worse Expanded Disability Status Scale score (Spearman ρ = −0.51; 95% CI, −0.85 to −0.02; <i>P </i>= .03). However, cortical volume and deep gray matter volume were not significantly different between the 2 groups, and they were not correlated with the Expanded Disability Status Scale. <h3>CONCLUSIONS:</h3> This study suggests that patients with MOGAD may have impaired glymphatic function, as measured by the ALPS index, which is associated with patient disability. Further study is warranted with a larger sample size.