title: Long-term evaluation of radiation-induced brain damage by serial magnetic resonance imaging.
abstract: The long-term changes during late delayed radiation-induced brain damage were investigated by serial magnetic resonance (MR) imaging of eight patients over a mean follow-up period of 45 months after irradiation. The radiation damage appeared as an enhanced lesion on T1-weighted MR images with gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) at 3 to 30 months after radiotherapy (mean 12.8 months). In all patients, an abnormal high signal intensity area on T2-weighted imaging preceded the enhanced lesion. The volume and number of enhanced lesions continued to increase for 3 to 23 months (mean 10.3 months). The high signal intensity area on T2-weighted imaging simultaneously expanded. The lesions were subsequently stabilized, and in four long-term survivors, the Gd-DTPA-enhanced lesions then decreased in size, the intervals from onset to regression were 12, 13, 17, and 35 months (mean 19.3 months), respectively. However, two patients showed a relapse of the enhanced lesion with latent periods of 8 and 9 months, respectively. Finally, the radiation-damaged brain became atrophic including the high signal intensity area on T2-weighted images. Late delayed radiation-induced brain damage continues to progress for over a year and then regresses, but thereafter a relapse may occur.
authors.affiliation: Department of Neurosurgery, University of Hokkaido School of Medicine, Sapporo.
authors.forename: T
authors.initials: T
authors.lastname: Kato
authors.forename: Y
authors.initials: Y
authors.lastname: Sawamura
authors.forename: M
authors.initials: M
authors.lastname: Tada
authors.forename: H
authors.initials: H
authors.lastname: Abe
authors.forename: H
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000528:radiation effects*; D001925:Brain Damage, Chronic / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013997:Time Factors