Arterial spin labeling perfusion MRI in pediatric arterial ischemic stroke: Initial experiences

Purpose: To investigate the feasibility and utility of arterial spin labeling (ASL) perfusion MRI for characterizing alterations of cerebral blood flow (CBF) in pediatric patients with arterial ischemic stroke (AIS). Materials and Methods: Ten children with AIS were studied within 4 to 125 hours following symptom onset, using a pulsed ASL (PASL) protocol attached to clinically indicated MR examinations. The interhemisphere perfusion deficit (IHPD) was measured in predetermined vascular territories and infarct regions of restricted diffusion, which were compared with the degree of arterial stenosis and volumes of ischemic infarcts. Results: Interpretable CBF maps were obtained in all 10 patients, showing simple lesion in nine patients (five hypo- perfusion, two hyperperfusion, and two normal perfusion) and complex lesions in one patient. Both acute and follow-up infarct volumes were significantly larger in cases with hypoperfusion than in either hyper- or normal perfusion cases. The IHPD was found to correlate with the degree of stenosis, diffusion lesion, and follow-up T ₂ infarct volumes. Mismatch between perfusion and diffusion lesions was observed. Brain regions presenting delayed arterial transit effects were tentatively associated with positive outcome. Conclusion: This study demonstrates the clinical utility of ASL in the neuroimaging diagnosis of pediatric AIS.