Introduction
Myelin oligodendrocyte glycoprotein (MOG) IgG antibody associated
disorders (MOGAD) describe a new entity of demyelinating neurological
syndromes defined by the presence of serum IgG autoantibodies against
MOG detected by cell-based assays (1–3). MOGAD occur in both children
and adults and comprise a heterogeneous disease spectrum (4,5). Clinical
presentation can include monophasic or recurrent episodes of optic
neuritis (ON), myelitis, brainstem syndromes, acute disseminated
encephalomyelitis (ADEM), and symptoms of encephalitis such as seizures
(6,7). Overall, MOGAD are rare with an incidence of around 1.1 - 2.4 per
million people (8) and are more frequent in children compared with
adults, as shown in a recent Dutch cohort with an incidence of 3.1 per
million in children (9).
Importantly, a direct pathophysiological effect of the MOG-IgG in the
central nervous system has yet to be elucidated (2). Therefore, it
remains unclear whether MOG-IgG has a direct pathogenic role or whether
it is rather a biomarker, that is a possible reflection of an
immunological response from disrupted myelin in the MOG-IgG associated
demyelinating disease spectrum. However, increasing clinical and
pathological evidence now strongly indicates that MOGAD represent a
distinct disease entity different from other neuroinflammatory and
demyelinating diseases, such as multiple sclerosis (MS) or aquaporin-4
(AQP4) IgG positive neuromyelitis optica spectrum disorder (NMOSD)
(10–15). Moreover, these conditions apparently exhibit differential
responses to immunotherapies, underscoring the necessity for accurate
and timely diagnostic procedures during which neuroimaging play a
paramount role (16–21). Due to the widespread nervous system affection
in MOGAD, magnetic resonance imaging (MRI) and optical coherence
tomography (OCT) are important imaging tools in gaining more knowledge
about the disease and for the monitoring of patients with this rare set
of disorders (22,23). This review article will give an overview of the
clinical, radiological, and advanced imaging aspects which are currently
of high interest in the MOGAD clinical research community.