Diffusion- andT2-Weighted Increases in Magnetic Resonance Images of Immature Brain during Hypoxia–Ischemia: Transient Reversal Posthypoxia

摘要: Abstract Hypoxic–ischemic changes in brain are detected earlier with diffusion-weighted (DW) than withT2-weighted magnetic resonance (MR) imaging techniques adults, whereas the response immature is not known. We investigated MR prior to, during, and/or after 2 h of hypoxia–ischemia (right carotid artery occlusion + 2 hypoxia) 7-day-old rats anesthetized isoflurane. In general, within first 45 min there were no DW orT2-weighted images. By second hour marked areas increased intensity inboththeT2and images, cortex and striatum being affected to thalamus hippocampus. The area exceeded that ofT2hyperintensities. was a transient recovery hyperintensities on bothT2and Between 24 72 hyperintense images decreased, onT2-weighted increased. distribution pathological damage assessed histologically correlated hyperintensity contrast adult brain, early hypoxic–ischemic injury as an increase both diffusion-and T2-weighted indicating unique alteration water dynamics this neonatal model hypoxia–ischemia. These alterations can rapidly but transiently reverse upon start normoxia reperfusion, suggestive secondary energy failure or delayed neuronal death.