An interventional study of Carbon Dioxide in Sickle Cell Disease and Cerebral Stroke, sponsored by Washington University School of Medicine. Recruiting at 1 site in United States. Open to participants aged 6 Years to 70 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-20.
Sponsored by Washington University School of Medicine · Not applicable, Interventional, and Basic science
The purpose of the study protocol is to identify imaging biomarkers for brain tissue under high metabolic stress at risk for permanent injury. We will measure oxygen extraction fraction (OEF) and cerebrovascular reactivity (CVR) in participants with and without perturbations in cerebral oxygen delivery over time to determine each parameter's role in clinical and radiologic neurologic outcomes. Measuring OEF can be done with specialized MRI sequences. Measuring CVR requires a vasoactive response, such as carbon dioxide. In order to deliver carbon dioxide evenly and as safely as possible, we will use RespirACT, an MRI-compatible device, to prevent over-breathing carbon dioxide and allow rapid steady-state physiology to minimize total scan time. We will also use a high density diffuse optical tomography (HD-DOT) cap to assess the measurement of OEF and CVR. This study will investigate both regional OEF and CVR simultaneously to understand each marker's unique developmental trajectory and contribution to stroke risk in children. This work will expand insights into mechanisms of stroke in children and assess the feasibility of the HD-DOT cap for obtaining these insights by comparing a cohort of optical CVR and a cohort of MRI CVR.
In addition to the MRI and/or HD-DOT cap with RespirAct, participants may also have their vitals measured, complete cognitive testing, and complete a blood draw with a study visit. Participants may be followed for up to three years and may complete both an MRI scan and an HD-DOT scan within 1 week-12 months of each other. Participants may be invited back to repeat MRI and/or HD-DOT scans 1-2 times over the next three years.
The purpose of the study protocol is to identify imaging biomarkers for brain tissue under high metabolic stress at risk for permanent injury. We will measure OEF and CVR in participants with and without perturbations in cerebral oxygen delivery over time to determine each parameter's role in clinical and radiologic neurologic outcomes. Measuring OEF can be done with specialized MRI sequences. Measuring CVR requires a vasoactive response, such as carbon dioxide. In order to deliver carbon dioxide evenly and as safely as possible, we will use RespirACT, an MRI-compatible device, to prevent over-breathing carbon dioxide and allow rapid steady-state physiology to minimize total scan time. We will also use an HD-DOT cap to assess the measurement of OEF and CVR.
Exclusion Criteria:
Other: Carbon Dioxide
Other: Carbon Dioxide
Participants inhale carbon dioxide, delivered by computer-controlled delivery system, to target specific levels of carbon dioxide while in magnetic resonance imaging scan and/or during HDDOT imaging to measure cerebrovascular reactivity.
HDDOT-Based Cerebrovascular Reactivity
Changes in relative concentration of deoxyhemoglobin with fluctuations of carbon dioxide as compared to gold standard measurement of MRI-based cerebrovascular reactivity.
Time frame: ~15 minutes during the MRI scan and ~60 minutes during the HDDOT imaging.
Cerebral Oxygen Metabolism
MRI-based cerebral based blood flow oxygen extraction fraction will be combined with laboratory data estimating arterial oxygen content to calculate cerebral oxygen metabolism.
Time frame: From administration of carbon dioxide to end of inhalation of carbon dioxide -- 60 minutes during MRI and/or HDDOT imaging.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Washington University School of Medicine