Cerebral blood flow and glucose metabolism in long-term survivors of childhood acute lymphoblastic leukaemia

Central nervous system treatment for childhood acute lymphoblastic leukaemi a (ALL) has been reported to cause changes in cerebral blood flow and gluco se metabolism. Little is known about the association of these functional ch anges with neuropsychological defects and structural changes. The aim of th e present study was to assess the relationship between changes in regional cerebral blood flow and glucose utilisation in long-term survivors of ALL, and the association of these functional abnormalities with neurocognitive a nd structural defects. 8 survivors of childhood ALL were studied with singl e photon emission tomography (SPECT) using Tc99m-ethyl cysteinate dimer (EC D) as tracer and with positron emission tomography (PET) using F-18-fluorod eoxyglucose (FDG) as tracer. 8 healthy controls also underwent FDG-PET. All subjects also underwent magnetic resonance imaging and neuropsychological assessment 5 years after cessation of the therapy. Focal cerebral blood flo w abnormalities were found in ECD-SPECT in 5 of the 8 survivors. Glucose ut ilisation appeared normal in the corresponding regions. However, glucose ut ilisation was decreased in thalamus and cerebellum in the survivors of ALL as compared with healthy controls. 3 patients had severe and 5 patients mil d neurocognitive difficulties. The changes in cerebral blood flow and I;DG uptake did not correspond neuroanatomically with the neurocognitive defects . Focal defects in cerebral blood flow in long-term survivors of ALL are no t associated with changes in local cerebral glucose utilisation. Neurocogni tive difficulties are not consistently associated with either changes in ce rebral blood flew or with decreased glucose utilisation. Therefore, based o n the present set of studies FDG-PET and ECD-SPECT cannot yet be recommende d for the evaluation of long-term neurocognitive defects associated with tr eatment of ALL. (C) 1999 Elsevier Science Ltd. All rights reserved.