STUDIES OF CEREBRAL BLOOD-FLOW IN CHILDREN WITH ACUTE LYMPHOBLASTIC-LEUKEMIA - CASE-REPORTS OF 6 CHILDREN TREATED WITH METHOTREXATE EXAMINED BY SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY

Purpose: Cranial irradiation has been widely used in order to prevent central nervous system (CNS) relapse of acute lymphoblastic leukemia ( ALL) in childhood. Owing to the risk of late side effects, the Nordic Society for Pediatric Hematology and Oncology (NOPHO) replaced CNS irr adiation with systemic high-dose methotrexate (HDMTX) in 1992. A prosp ective study of the effects of HDMTX and intrathecal MTX on CNS functi on is in progress at our center. Patients and Methods: Six ALL patient s underwent Tc-99m-HMPAO single-photon emission computed tomography (S PECT) examination of regional cerebral blood flow (rCBF): three owing to neurological symptoms during treatment for ALL and the other three as part of the study. Results: All the patients had various degrees of disturbed rCBF, which was more pronounced in the patients with neurol ogical symptoms. One patient had severe symptoms and impaired rCBF aft er three intrathecal injections of MTX but before administration of HD MTX. Conclusions: Impaired cerebral perfusion was found in patients wi th and without neurological symptoms during treatment for ALL. The imp act of these findings is still unknown, from both the long- and the sh ort-term perspective. The possibility that intrathecal MTX alone or in combination with HDMTX may affect rCBF through vascular damage should be further investigated, in terms of both mechanisms and clinical sig nificance.