To build a functional neuroimaging atlas of cerebrovascular reactivity data in healthy children. 

Cerebrovascular reactivity (CVR) can be measured by changing arterial blood carbon dioxide (CO₂) content and measuring subsequent changes in blood flow. Functional MRI blood oxygen level dependent sequences (BOLD) are used to detect this change. Aberrations in CVR scans can serve as a biomarker of ischemic risk. Data describing the normal range of CVR values in healthy children is needed to allow characterization of observed pathological aberrations in CVR in patient studies. 

Prospective enrollment of healthy children ages 6 to 18. Target N of 40. Two datasets generated within the atlas using two different techniques of administering (CO₂): a breath-hold CVR dataset (endogenous stimulus) and a RespirAct^TM CVR dataset (exogenous). A test of normality is performed on CVR values for each voxel across subjects, with mean and standard deviation calculations. This will allow for generation of a Z-score for each CVR value per voxel in any clinical CVR study. Voxel-wide validation of breath-hold CVR values against the gold standard RespirAct^TM CVR values will be performed using within subject t-test and between group comparisons. Subgroup analysis based on gender and age will also be performed. 

CVR data for 8 healthy right-handed children is presented (4 female, median age 13, range 9 -14 years). All participants tolerated CVR studies with no side effects reported.  Group datasets acquired passed tests of normality with no significant differences in CVR values between the two methods found. 

CVR neuroimaging studies are performed in patients with a risk of recurrent arterial ischemic strokes, such as those with intracranial arteriopathies and sickle cell disease. Our atlas can provide clinicians with information regarding extent and distribution of CVR abnormalities, allow for stroke risk stratification, and aid in determining the optimal time for surgical and other interventions.