LARGE INTRACRANIAL VESSEL OCCLUSIVE VASCULOPATHY AFTER RADIATION-THERAPY IN CHILDREN - CLINICAL-FEATURES AND USEFULNESS OF MAGNETIC-RESONANCE-IMAGING

Purpose: To assess the relationship between large intracranial vessel occlusive vasculopathy (vasculopathy) and radiation therapy, and to cl arify the clinical efficacy of magnetic resonance (MR) imaging in the diagnosis and screening of the vasculopathy. Methods and Materials: We retrospectively evaluated the medical records and serial MR images fo r 32 pediatric patients, in whom radiation therapy had been given to f ields including the circle of Willis and major cerebral arteries. All children had periodically undergone follow-up neurologic assessment an d MR imaging examinations at Kanagawa Children's Medical Center for mo re than one year after radiation therapy (range 1.3-14 years). Patient s who had not remained free of tumor progression up to the time of fin al evaluation were excluded. Results: Vasculopathy developed in 6 of 3 2 patients 2-13 years after radiation therapy, Three of them presented with transient ischemic attacks (TIA) and the other three showed infa rctions without preceding TIA, Steno-occlusive changes of major cerebr al arteries were identified by MR imaging in all six patients, but not obtained in the remaining 26 patients, In the patients with TIA, MR i maging demonstrated steno-occlusive changes at the time of TIA, before irreversible infarction, They have been doing well subsequent to ence phaloduroarteriosynangiosis, In the three patients who presented infar ction without preceding TIA, MR imaging did not demonstrate the vascul ar change before the onset of infarction, and two of them developed ne urologic deficits, The mean exposure dose for the circle of Willis and major cerebral arteries in these six patients was significantly highe r than that in the remaining 26 patients without this sequela (61Gy vs , 50Gy, p < 0.05). The mean age at radiation therapy of the six patien ts was lower, but the difference was not significant. Conclusion: The incidence of vasculopathy after radiation therapy has a considerable c orrelation with radiation dose and age at radiation therapy, MR examin ation is useful for the diagnostic evaluation of vasculopathy, and it is also effective in screening for vasculopathy in patients with TIA, and may be helpful in the prevention of neurologic sequela. (C) 1997 E lsevier Science Inc.