Perfusion imaging in the pediatric patient.

The prevalence of cerebrovascular disease in children is much higher than most clinicians and neuroradiologists suspect, when all primary and secondary causes are considered. Most signal alterations found on MR imaging in childhood central nervous system pathologic conditions result from causes other than a decrease in tissue perfusion. In addition to conventional MR imaging, the ability to assess changes in tissue water by diffusion imaging and tissue perfusion by perfusion-weighted imaging can prove useful to asses cerebral hemodynamics in various pathologic disorders. Exogenous contrast bolus dynamic perfusion-weighted imaging is especially useful in children to differentiate between ischemic injury and other conditions that may alter T2 relaxation, such as demyelination and edema. Perfusion imaging has proved to be a robust and valuable tool to assess the hemodynamic component in childhood CNS disease related to neoplasms and complications from their therapy, cerebrovascular occlusive disease, childhood CNS arteriopathies and trauma.