title: Increased metabolic activity in the spinal cord of patients with long-standing Lhermitte's sign.
abstract: OBJECTIVE
  To investigate the pathophysiology of the radiation-induced, chronic Lhermitte's sign (LS) on the basis of long-standing case histories with partial functional recovery.
  
  
  METHODS
  As radiotherapy in two nasopharyngeal cancer patients, a biologically effective dose (BED) of 103.8 Gy(2) (case 1) and 94.8 Gy(2) (case 2) was delivered to the cervical spinal cord. Neurologic signs relating to the irradiated spinal cord segments developed after 2 months (case 1) and 5 years (case 2), with radiation-induced damage equivalent to grade 3 (case 1) and grade 2 (case 2) toxicity (Common Toxicity Criteria, Version 2.0). The clinical status improved to grade 2 (case 1) and grade 1 (case 2). Positron emission tomography (PET) and fibroblast clonogen assay were applied 25 and 7 years postirradiation, respectively, to characterize this rare clinical picture.
  
  
  RESULTS
  PET demonstrated increased [(18)F]fluorodeoxyglucose (FDG) accumulation and [(15)O]butanol perfusion, but negligible [(11)C]methionine uptake in the irradiated spinal cord segments in both patients. In clonogenic assays, fibroblasts from case 1 displayed much higher radiation sensitivity than in healthy controls, while in case 2 the fibroblasts sensitivity was normal.
  
  
  CONCLUSIONS
  These data suggests a close direct relationship between regional perfusion and metabolism of the spinal cord, similarly as in the brain. The postirradiation recovery may be related to energy-demanding conduction, explaining the increased metabolism and perfusion. The increased radiosensitivity and higher spinal cord BED may have contributed to the more severe sequelae in case 1.
authors.affiliation: Department of Oncotherapy, Semmelweis University, Budapest, Hungary. esik@oncol.hu
authors.forename: Olga
authors.initials: O
authors.lastname: Esik
authors.forename: Tibor
authors.initials: T
authors.lastname: Csere
authors.forename: Klára
authors.initials: K
authors.lastname: Stefanits
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Szakáll
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lengyel
authors.forename: Géza
authors.initials: G
authors.lastname: Sáfrány
authors.forename: Katalin
authors.initials: K
authors.lastname: Vönöczky
authors.forename: Erzsébet
authors.initials: E
authors.lastname: Lengyel
authors.forename: Judit
authors.initials: J
authors.lastname: Olajos
authors.forename: Gábor
authors.initials: G
authors.lastname: Bajzik
authors.forename: Lajos
authors.initials: L
authors.lastname: Trón
mesh_terms: D000328:Adult; D005260:Female; D005347:Fibroblasts / Q000528:radiation effects; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006689:Hodgkin Disease / Q000532:radiotherapy*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008715:Methionine / Q000378:metabolism; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*; D011836:Radiation Tolerance; D019275:Radiopharmaceuticals; D011878:Radiotherapy / Q000009:adverse effects*; D011879:Radiotherapy Dosage; D013116:Spinal Cord / Q000378:metabolism* / Q000528:radiation effects*; D013118:Spinal Cord Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology*; D013997:Time Factors; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D008715:Methionine