title: Radiation myelopathy in over-irradiated patients: MR imaging findings.
abstract: The objective of this work is to report the MRI findings in patients with radiation myelopathy due to accidental local over-irradiation syndrome. Eight patients (seven males and one female) were suffering from over-irradiation syndrome as a result of treatments from a malfunctioning linear electron accelerator. The mean accidental estimated dose was 136 Gy delivered to the "open-neck" (seven cases) and to the thoracic wall (one case), during a mean of 5.4 sessions (range 1-9 sessions). Paresthesia and weakness in the upper extremities were the earliest symptoms (87.5 %), with evolution to paralysis in all patients. No patient is alive (mean survival time 64 days). In all cases MRI was negative for neurologic lesions in the acute phase ( < 90 days from irradiation; Radiation Therapy Oncology Group scoring system). Late signs of radiation myelitis manifested as high-intensity signals on T2-weighted images in three patients, and as Gd-DTPA enhancement of T1-weighted images in one case. Autopsies performed on four patients who died in acute phase showed morphologic alterations in white matter: edema in 75 %, and necrosis and glial reaction as well as obliterative vasculitis in all cases. In cases of over-irradiation, MRI may be normal in acute phase even if the patients have severe neurologic deficit, as positive MRI findings appear only in delayed radiation myelitis.
authors.affiliation: Radiology Service, Hospital Clínico Universitario, C/San Juan Bosco 15, E-50 009 Zaragoza, Spain.
authors.forename: E R
authors.initials: ER
authors.lastname: Alfonso
authors.forename: M A
authors.initials: MA
authors.lastname: De Gregorio
authors.forename: P
authors.initials: P
authors.lastname: Mateo
authors.forename: R
authors.initials: R
authors.lastname: Escó
authors.forename: N
authors.initials: N
authors.lastname: Bascón
authors.forename: F
authors.initials: F
authors.lastname: Morales
authors.forename: R
authors.initials: R
authors.lastname: Bellosta
authors.forename: P
authors.initials: P
authors.lastname: López
authors.forename: M
authors.initials: M
authors.lastname: Gimeno
authors.forename: M
authors.initials: M
authors.lastname: Roca
authors.forename: J L
authors.initials: JL
authors.lastname: Villavieja
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000532:radiotherapy; D005260:Female; D006801:Humans; D007822:Laryngeal Neoplasms / Q000532:radiotherapy; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009187:Myelitis / Q000175:diagnosis* / Q000209:etiology*; D010315:Particle Accelerators; D011832:Radiation Injuries / Q000175:diagnosis*; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D013116:Spinal Cord / Q000473:pathology