Sebastian Lopez Chiriboga’s research while affiliated with University of Sassari and other places

White matter tracts within the central nervous system are organized into ascending and descending pathways that transmit sensory input and motor output, respectively. Tractopathy, or damage to these tracts, can impair sensory or motor functions. Motor neuron diseases are pathologic processes affecting the upper or lower motor neurons. Amyotrophic lateral sclerosis (ALS) is the most common form of acquired motor neuron disease. Traditionally, ALS has affected upper and lower motor neurons of the extremities, torso, and head and neck. There are several ALS variants, some of which affect only the upper motor neurons (eg, primary lateral sclerosis), lower motor neurons (eg, progressive muscular atrophy), or motor neurons of the head and neck (eg, progressive bulbar palsy). Characteristic imaging features of ALS include abnormal T2 hyperintensity within the brain along the corticospinal tract, as well as cortical susceptibility signal intensity along the precentral gyrus, termed the "motor band" sign. Spinal muscular atrophy is a less common primary motor neuron disease and appears on images as atrophy of the anterior horn of the spinal cord, as well as proximal muscle atrophy. In addition to pure motor neuron diseases, there are numerous toxic and metabolic conditions, genetic disorders, infectious diseases, and immune-mediated disorders that can secondarily affect the corticospinal tracts (corticospinal tractopathies), producing symptoms of upper motor neuron injury. These tractopathies are visible at MRI as T2-hyperintense lesions along varying segments of the corticospinal tract. A comprehensive diagnostic approach that integrates clinical symptoms with radiologic and laboratory findings is crucial to distinguish among these varied conditions. ©RSNA, 2024 Supplemental material is available for this article.

Purpose of review: This article provides an update on the clinical diagnosis and management of immune-mediated myelopathies, including the relevance of imaging, ancillary testing with an emphasis on autoantibody biomarkers, recognition of myelitis mimics, and therapeutic approach. Recent findings: The imaging characterization of immune-mediated myelopathies and the discovery of neural autoantibodies have been crucial in improving our ability to accurately diagnose myelitis. The identification of autoantibodies directed against specific central nervous system targets has led to major improvements in our understanding of the mechanisms underlying inflammation in myelitis. It has also allowed distinction of these myelopathy etiologies from noninflammatory etiologies of myelopathy and from multiple sclerosis and provided insight into their risk of recurrence, treatment response, and long-term clinical outcomes. Prompt recognition and appropriate testing in the setting of acute and subacute myelopathies is critical as timely administration of immunotherapy can help improve symptoms and prevent permanent neurologic disability. A patient should not be classified as having "idiopathic transverse myelitis" without a comprehensive evaluation for a more specific etiology. Achieving the correct diagnosis and learning to recognize noninflammatory myelitis mimics is crucial as they have therapeutic and prognostic implications. Summary: Identifying the clinical and radiographic features of immune-mediated myelitis and recognizing mimics and pitfalls will help clinicians treat confirmed autoimmune myelitis appropriately.