Acute injury to the immature brain with hypoxia with or without hypoperfusion.

This article reviews the imaging features and evolution of immature brain injury caused by hypoxia with or without hypoperfusion in the neonate and young child. Clinical presentations and available literature on mechanisms and clinical outcomes are discussed. In many of these cases, diffusion-weighted imaging does not show the full extent of the injury but detects a pattern of injury that is important in guiding clinical care. Awareness of the delayed cell death mechanisms is essential to understand diffusion-weighted imaging sensitivity and evolution and to provide the most accurate clinical interpretation, especially in cases of hypoxia with or without hypoperfusion.