Pediatric cerebrovascular disease.

Stroke in children is thought to be a rare phenomenon, but in a pediatric hospital, it is much more common than is expected. The development of rapid MRI imaging with diffusion techniques and MR spectroscopy has brought to the attention of both the neuroradiologists and clinicians that pediatric infarction, in both detection and management, are challenges for the future. Since 1995, cerebral diffusion has been performed at The Children's Hospital of Philadelphia in the evaluation of patients with acute cerebral compromise. Diffusion imaging looks at the motion of water molecules both intra- and extracellular, and the manner in which they become restricted in their motion when higher gradient strength is applied during the imaging sequence. Restricted diffusion is seen in cytotoxic edema, an early acute manifestation of ischemia/infarction. Diffusion studies are often positive when routine MRI and CT are as yet negative. Confirmation of the death of tissue is provided on proton spectroscopy by a rise in lactate from anaerobic glycolysis and a loss of N-acetylaspartate from neuronal death. Confirmation of the diffusion image findings, by mapping the apparent co-efficient (ADC), is also valuable. Application of these techniques, together with magnetic resonance angiography and magnetic resonance venography, is the substance of this paper.