Abstract 65: Cerebrovascular Reactivity Imaging Is Well Tolerated In Children With And Without Sickle Cell Disease

Abstract

Background: Cerebrovascular reactivity (CVR) refers to a stimulus-induced change in blood flow, reflecting hemodynamic reserve. Carbon dioxide (CO 2 ) stimulus increases cerebral blood flow (CBF), and exogenous noninvasive CO 2 with concurrent MRI is an established CVR method in adults. However, children with and without sickle cell disease (SCD) have increased resting CBF compared to adults, and few studies have examined CVR in children. Our objective was to determine tolerability of CO 2 CVR MRI in children with and without SCD. Methods: Children undergoing CO 2 CVR MRI had post-scan assessments of their experience and comfort during CVR testing. This included a preference rating ranking 8 experiences, including CVR MRI, in order from most to least enjoyable, a 6-point comfort scale, and a yes/maybe/no question asking if they would do CVR MRI again. The 8 preference items were grouped into quartiles for analysis. The Wilcoxon test was used to compare comfort rating based on SCD status and quartile preference rankings. Spearman’s correlation was used to compare peak end-tidal CO 2 with comfort rating. Results: Nine children with SCD and 22 controls ages 8-21 years old completed CVR MRI, with a median peak end-tidal CO 2 of 50 mmHg [IQR 47, 51]. No child had a serious adverse event. On a 6-point scale, the median comfort rating was 4 (slightly uncomfortable) [IQR 2,4]. There was no difference in comfort based on SCD status (p=0.70) or peak end-tidal CO 2 (p=0.65). Across all participants, CVR fell in the 3rd preference quartile. CVR rated similarly to visiting the dentist (p=0.95), but was better than throwing up (p=0.03). Despite ranking the scan in the 3 rd quartile, the majority reported willingness to repeat CVR MRI, and only one participant (control) said they would not. Conclusion: Noninvasive CO 2 CVR imaging is safe and tolerable in children with and without SCD. After completing the session, most children would be willing to undergo similar testing again.