Abstract #1634

An Alternative Technique for Measuring Cerebrovascular Reactivity; Comparing Cued Deep Breathing Hypocapnia with Inspiration of Carbon Dioxide

Molly Gallogly Bright^1,2, Daniel P. Bulte², Peter Jezzard², Jeff H. Duyn¹

¹Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, USA; ²FMRIB Centre, Department of Clinical Neurology, University of Oxford, Oxford, UK

Recently we introduced a novel respiratory technique, cued deep breathing (CDB), which induces robust BOLD signal decreases. The strong, short-lived response to CDB allows for whole-brain spatial and temporal characterization of cerebrovascular reactivity, and CDB is suitable for a broad range of clinical situations. We have directly compared the quantitative effects on end-tidal gas levels and BOLD signal of CDB and a traditional hypercapnia 4% CO2 gas challenge. CDB induced up to 7.00.7 mmHg decreases in end-tidal CO2 and the resulting reactivity maps show good correlation with the CO2 study, indicating CDB offers easy access to similar information.