{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:51:17Z","timestamp":1782489077898,"version":"3.54.5"},"reference-count":12,"publisher":"BMJ","issue":"4","license":[{"start":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T00:00:00Z","timestamp":1775606400000},"content-version":"unspecified","delay-in-days":7,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,3,7]]},"published-print":{"date-parts":[[2026,4]]},"abstract":"<jats:p>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.<\/jats:p>","DOI":"10.1136\/bcr-2025-270652","type":"journal-article","created":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T10:55:23Z","timestamp":1775645723000},"page":"e270652","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Disappearing corticospinal tract on routine MRI: dynamic signal evolution in primary lateral sclerosis"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7479-4489","authenticated-orcid":false,"given":"Christian","family":"Marques Couto","sequence":"first","affiliation":[{"name":"Neurology, Centro Internacional SARAH de Neurorreabilita\u00e7\u00e3o e Neuroci\u00eancias, Rio de Janeiro, Brazil"},{"name":"Neurology, Universidade Federal Fluminense Hospital Universitario Antonio Pedro, Niter\u00f3i, RJ, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Silma Amanda Marques Caetano","family":"Gomes","sequence":"additional","affiliation":[{"name":"Neurology, SARAH Network of Rehabilitation Hospitals, Rio de Janeiro, Rio de Janeiro, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ricardo Silva","family":"Carvalho","sequence":"additional","affiliation":[{"name":"Radiology Department, SARAH Network of Rehabilitation Hospitals, Bras\u00edlia, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Osvaldo JM","family":"Nascimento","sequence":"additional","affiliation":[{"name":"Neurology, Universidade Federal Fluminense Hospital Universitario Antonio Pedro, Niter\u00f3i, RJ, Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,4,8]]},"reference":[{"key":"2026062608154055000_19.4.e270652.1","doi-asserted-by":"publisher","DOI":"10.1136\/jnnp-2019-322541"},{"key":"2026062608154055000_19.4.e270652.2","doi-asserted-by":"crossref","DOI":"10.3389\/fneur.2022.947347","article-title":"Structural magnetic resonance imaging findings and histopathological correlations in motor neuron diseases-A systematic review and meta-analysis","volume":"13","author":"Zejlon","year":"2022","journal-title":"Front Neurol"},{"key":"2026062608154055000_19.4.e270652.3","doi-asserted-by":"publisher","DOI":"10.1111\/ane.12863"},{"key":"2026062608154055000_19.4.e270652.4","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1111\/jon199774208","article-title":"Degeneration of the pyramidal tracts in patients with amyotrophic lateral sclerosis. A premortem and postmortem magnetic resonance imaging study","volume":"7","author":"Abe","year":"1997","journal-title":"J Neuroimaging"},{"key":"2026062608154055000_19.4.e270652.5","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1111\/ncn3.12165","article-title":"Serial changes of corticospinal tract hyperintensity on magnetic resonance imaging from the preclinical stage in amyotrophic lateral sclerosis","volume":"6","author":"Takizawa","year":"2018","journal-title":"Neurology & Clinical Neurosc"},{"key":"2026062608154055000_19.4.e270652.6","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-510X(02)00104-1"},{"key":"2026062608154055000_19.4.e270652.7","doi-asserted-by":"publisher","DOI":"10.3174\/ajnr.A3114"},{"key":"2026062608154055000_19.4.e270652.8","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-510X(01)00503-2"},{"key":"2026062608154055000_19.4.e270652.9","doi-asserted-by":"crossref","first-page":"1281","DOI":"10.1007\/s00330-020-07239-0","article-title":"A susceptibility-weighted imaging qualitative score of the motor cortex may be a useful tool for distinguishing clinical phenotypes in amyotrophic lateral sclerosis","volume":"31","author":"Conte","year":"2021","journal-title":"Eur Radiol"},{"key":"2026062608154055000_19.4.e270652.10","doi-asserted-by":"crossref","first-page":"7677","DOI":"10.1007\/s00330-023-10070-y","article-title":"Amyotrophic lateral sclerosis with upper motor neuron predominance: diagnostic accuracy of qualitative and quantitative susceptibility metrics in the precentral gyrus","volume":"33","author":"Lo Russo","year":"2023","journal-title":"Eur Radiol"},{"key":"2026062608154055000_19.4.e270652.11","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0035241","article-title":"Iron accumulation in deep cortical layers accounts for MRI signal abnormalities in ALS: correlating 7 tesla MRI and pathology","volume":"7","author":"Kwan","year":"2012","journal-title":"PLoS One"},{"key":"2026062608154055000_19.4.e270652.12","doi-asserted-by":"publisher","DOI":"10.1111\/jon.12127"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2025-270652","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:21:32Z","timestamp":1782487292000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2025-270652"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4]]},"references-count":12,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,4,8]]},"published-print":{"date-parts":[[2026,4]]}},"alternative-id":["10.1136\/bcr-2025-270652"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2025-270652","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4]]}}}