A window into the future? MRI for evaluation of neuromyelitis optica spectrum disorder throughout the disease course

Abstract

Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, inflammatory disease of the central nervous system marked by relapses often associated with poor recovery and long-term disability. Magnetic resonance imaging (MRI) is recognized as an important tool for timely diagnosis of NMOSD as, in combination with serologic testing, it aids in distinguishing NMOSD from possible mimics. Although the role of MRI for disease monitoring after diagnosis is not as well established, MRI may provide important prognostic information and help differentiate between relapses and pseudorelapses. Increasing evidence of subclinical disease activity and the emergence of newly approved, highly effective immunotherapies for NMOSD adjure us to re-evaluate MRI as a tool to guide optimal treatment selection and escalation throughout the disease course. In this article we review the role of MRI in NMOSD diagnosis, prognostication, disease monitoring, and treatment selection.

MR T2-relaxation time as an indirect measure of brain water content and disease activity in NMOSD

“…The presence of occult brain damage is controversial in patients with NMOSD. Most studies using diffusion-weighted imaging, magnetisation transfer imaging or proton MR spectroscopy, documented no demyelination or selective alterations of the visual pathway or corticospinal tract 21. This was also pathologically proven in the cortex of 19 patients with NMOSD, where no evidence of cortical demyelination was detected 22.…”

Pregnancy-Related Attack in Neuromyelitis Optica Spectrum Disorder With AQP4-IgG: A Single-Center Study and Meta-Analysis

“…Referring to previous research ( 22 ), the definitions used in the current study were as follows: (1) informative pregnancies were defined as all pregnancies occurring after the onset of NMOSD as well as all patients in whom the disease presented during the pregnancy or within 12 months postpartum; (2) PRA was defined as onset or relapse occurring during pregnancy or within 12 months after delivery or abortion; (3) relapses were defined as new or substantially worsened neurological symptoms lasting for at least 24 hours and a new or enhancing lesion on MRI so as to exclude pseudorelapses ( 23 ); (4) pregnancy with IS treatment was defined as a pregnancy in which the patient was on IS treatment (including corticosteroids, azathioprine [AZA], or rituximab) during at least 7 months of the pregnancy; (5) pregnancy without IS treatment was defined as a pregnancy in which the patient did not receive any IS treatment before or during pregnancy; and (6) miscarriage was defined as a spontaneous loss of intrauterine pregnancy during the first 24 weeks.…”

Advanced MRI quantification of neuroinflammatory disorders

“…One of the foremost MS mimics to consider, which was previously considered to be a severe optic-spinal MS variant (Lennon et al, 2004(Lennon et al, , 2005, is the neuromyelitis optica spectrum disorders (NMOSD). This overlap is particularly due to the relapsing clinical nature of NMOSD, which shares considerable overlap with the relapsing-remitting (RRMS) subtype of MS and radiological features, as emphasized in Figure 1a (Geraldes et al, 2018;Solomon et al, 2021). Differentiating NMOSD from MS is of significant importance for patients, particularly considering that the treatment options and prognosis vary (Piehl, 2021;Wallach et al, 2021).…”

“…AQP4 + , aquaporin 4 seropsitivity; FLAIR, fluid attenuated inversion recovery; mm, millimeter; NODDI, neurite orientation density and dispersion imaging; NMOSD, neuromyelitis optica spectrum disorders; PPMS, primary progressive multiple sclerosis; RRMS, relapsing-remitting multiple sclerosis; SPMS, secondary progressive multiple sclerosis brain regions and the spinal cord (Bakshi et al, 2008;Thompson et al, 2018). Whereas characteristic MRI-based pathology in NMOSD will more often occur in the form of (i) periependymal brain lesions, (ii) extensive optic nerve lesions, and (iii) longitudinally extensive transverse myelitis (LETM) of the spinal cord (Solomon et al, 2021). However, conventional MRI lacks specificity to some of the various targets and processes associated with neuroinflammatory disorders.…”

“…Diagnostically characteristic MS lesions will occur in periventricular, cortical/juxtacortical, and infratentorial brain regions and the spinal cord (Bakshi et al, 2008; Thompson et al, 2018). Whereas characteristic MRI‐based pathology in NMOSD will more often occur in the form of (i) periependymal brain lesions, (ii) extensive optic nerve lesions, and (iii) longitudinally extensive transverse myelitis (LETM) of the spinal cord (Solomon et al, 2021). However, conventional MRI lacks specificity to some of the various targets and processes associated with neuroinflammatory disorders.…”