Comparative Analysis of Cerebrovascular Techniques for Studying Cognitive Aging

Cerebrovascular reactivity (CVR) is a dynamic measurement of brain vascular health that may be used to determine age-related increases in cerebrovascular disease risk. CVR may be quantified as the increase in cerebral blood flow (CBF) from rest in response to a vasodilatory challenge, which reflects the ability of cerebral blood vessels to respond to stimuli. Hypercapnia is a vasodilatory stimulus that can be achieved by delivering air supplemented with additional carbon dioxide (CO 2 ) using an end tidal targeting system or achieved by a breath hold which can naturally increase CO 2 . A direct measurement of CBF can be performed using magnetic resonance imaging (MRI). However, this technique requires access to both an MRI and a specialized gas delivery system, which are expensive. An indirect measurement of CBF can be performed using a transcranial Doppler ultrasound (TCD), which is significantly less expensive and requires less equipment. The purpose of this study is to perform a comparative analysis between the breath-hold TCD-CVR technique with a more gold-standard MRI-CVR technique in middle-aged adults. If the breath-hold TCD-CVR technique demonstrates a high reliability and validity with the MRI-CVR technique, then it could serve as a cost-effective and more practical replacement option. American Heart Association Grant 24IAUST1199297 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.