Neuroimaging features in inflammatory myelopathies: A review

Abstract

Spinal cord involvement can be observed in the course of immune-mediated disorders. Although multiple sclerosis (MS) represents the leading cause of inflammatory myelopathy, an increasing number of alternative etiologies must be now considered in the diagnostic work-up of patients presenting with myelitis. These include antibody-mediated disorders and cytotoxic T cell-mediated diseases targeting central nervous system (CNS) antigens, and systemic autoimmune conditions with secondary CNS involvement. Even though clinical features are helpful to orient the diagnostic suspicion (e.g., timing and severity of myelopathy symptoms), the differential diagnosis of inflammatory myelopathies is often challenging due to overlapping features. Moreover, noninflammatory etiologies can sometimes mimic an inflammatory process. In this setting, magnetic resonance imaging (MRI) is becoming a fundamental tool for the characterization of spinal cord damage, revealing a pictorial scenario which is wider than the clinical manifestations. The characterization of spinal cord lesions in terms of longitudinal extension, location on axial plane, involvement of the white matter and/or gray matter, and specific patterns of contrast enhancement, often allows a proper differentiation of these diseases. For instance, besides classical features, such as the presence of longitudinally extensive spinal cord lesions in patients with aquaporin-4-IgG positive neuromyelitis optica spectrum disorder (AQP4+NMOSD), novel radiological signs (e.g., H sign, trident sign) have been recently proposed and successfully applied for the differential diagnosis of inflammatory myelopathies. In this review article, we will discuss the radiological features of spinal cord involvement in autoimmune disorders such as MS, AQP4+NMOSD, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and other recently characterized immune-mediated diseases. The identification of imaging pitfalls and mimics that can lead to misdiagnosis will also be examined. Since spinal cord damage is a major cause of irreversible clinical disability, the recognition of these radiological aspects will help clinicians achieve a correct and prompt diagnosis, treat early with disease-specific treatment and improve patient outcomes.

Non‐demyelinating disorders mimicking and misdiagnosed asNMOSD:a literature review

“…Gadolinium lesion enhancement during acute attacks is seen in >90% of patients with NMOSD and its absence should prompt the consideration of other etiologies [5]. Persistent enhancement over >3 months is also unusual in NMOSD but can be seen in neurosarcoidosis or neoplasms (Figure 2) [25]. Lastly, fever and constitutional symptoms may rarely be seen in patients with NMOSD but should prompt extensive screening for infectious etiologies (including bacteria, mycobacteria, fungi, and viruses).…”

Cervical myelitis: a practical approach to its differential diagnosis on MR imaging

“…1) (▶ Fig. 6-8) [1][2][3][4]16]. The longitudinal extent on sagittal T2WI with variable hyperintense signal changes often spans several vertebral body segments [1][2][3][4]6].…”

“…Postcontrast (pc) T1WI may disclose slight or even no parenchymal contrast enhancement, whereas leptomeningeal enhancement is more frequent [3,17,25,26]. Comparison of lesion evolution across MOGAD, AQP4-NMOSD, and MS shows that clinically leading MS-associated spinal lesions are preferentially located in the cervical region and to a lesser extent in the thoracic region of the spine [3,17]. By contrast, thoracic spinal cord involvement is more common in AQP4 -NMOSD and MOGAD.…”

“…The longitudinal extent on sagittal T2WI with variable hyperintense signal changes often spans several vertebral body segments [1][2][3][4]6]. Involvement of specific spinal cord tracts, the presence of perimedullary T2 flow voids, or evidence of restricted diffusion may narrow down the differential diagnosis [1][2][3][4]6]. Subacute combined degeneration of the spinal cord (SCDSC) depicts the alteration of the dorsal and/or lateral columns that are most commonly due to vitamin B12 deficiency (funicular myelosis) [1-3, 5, 6, 16, 94].…”

MRI to differentiate multiple sclerosis, neuromyelitis optica, and myelin oligodendrocyte glycoprotein antibody disease

“…93 LETM is the most relevant radiological finding in AQP4-ab-positive NMOSD, with it being helpful for distinguishing NMSOD from MS, but not MOGAD. 94 As in MS, the cervical spine is the most common location in NMOSD patients. Sometimes, cervical lesions can extend into the thoracic cord or into the brainstem up to the area postrema (as described in 19% of cervical LETM in AQP4-ab-positive NMOSD patients).…”