{
  "abstract": "Primary lateral sclerosis (PLS) may show corticospinal tract (CST) hyperintensity on fluid-attenuated inversion recovery and motor cortex hypointensity on susceptibility-weighted imaging (SWI); however, its longitudinal evolution remains poorly understood. Here, we describe two cases with definite PLS, who were followed up for 15 and 6 years and assessed using qualitative visual magnetic resonance imaging (MRI) scores. Both patients initially exhibited CST hyperintensity. Despite progressive clinical deterioration due to wheelchair/walker dependence, serial MRI demonstrated complete CST normalisation (score 0/16). Concurrently, SWI revealed progressive motor cortex hypointensity, consistent with iron deposition. These cases illustrate a possible dissociation between conventional and susceptibility-based MRI markers, suggesting dynamic pathophysiological processes and potentially early inflammation followed by gliotic remodelling, although technical factors cannot be excluded. A normal-appearing CST should not exclude advanced PLS, and progressive motor cortex hypointensity may provide a more stable marker. Prospective studies with standardised protocols are required to validate these observations.",
  "authors": [
    {
      "affiliations": [
        "Neurology, Centro Internacional SARAH de Neurorreabilitação e Neurociências, Rio de Janeiro, Brazil",
        "Neurology, Universidade Federal Fluminense Hospital Universitario Antonio Pedro, Niterói, RJ, Brazil"
      ],
      "name": "Christian Marques Couto"
    },
    {
      "affiliations": [
        "Neurology, SARAH Network of Rehabilitation Hospitals, Rio de Janeiro, Rio de Janeiro, Brazil"
      ],
      "name": "Silma Amanda Marques Caetano Gomes"
    },
    {
      "affiliations": [
        "Radiology Department, SARAH Network of Rehabilitation Hospitals, Brasília, Brazil"
      ],
      "name": "Ricardo Silva Carvalho"
    },
    {
      "affiliations": [
        "Neurology, Universidade Federal Fluminense Hospital Universitario Antonio Pedro, Niterói, RJ, Brazil"
      ],
      "name": "Osvaldo JM Nascimento"
    }
  ],
  "title": "Disappearing corticospinal tract on routine MRI: dynamic signal evolution in primary lateral sclerosis",
  "uid": "b0ecde60-09a3-5db7-8544-4b3ce4c051a8"
}