Brain Blood Flow: Age and Gender

University of Wisconsin, Madison46 enrolled

Overview

Baseline cerebral blood flow through the middle cerebral artery (MCA) and cerebral vasodilator response of the MCA to inhaled carbon dioxide (CO2) will be measured in young women, young men, older women, and older men using Magnetic Resonance (MR) imaging and transcranial Doppler ultrasound (TCD). Data collection techniques will be compared.

The investigators have recently shown that cerebral blood flow responses to chemical stimuli are reduced in healthy older adults. The investigators also have preliminary data suggesting that sex differences in cerebrovascular regulation exist. The overall goal of this application is to extend on the investigators previous studies by employing advanced neuroimaging techniques to enhance the investigators understanding of neurovascular coupling in healthy aging. This study will collect clinically significant data with implications for the future risk of cognitive decline and Alzheimer's disease. The research aims are: 1. To determine the effect of age and sex on baseline cerebral blood flow through the middle cerebral artery (MCA). 2. To determine the effect of age and sex on cerebral vasodilator responses. 3. To determine if the cerebrovascular responses measured by transcranial Doppler ultrasound (TCD) are associated with the cerebrovascular responses measured by Magnetic Resonance (MR) imaging.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Healthy Aging

Interventions

MRIDEVICE

Participants will undergo a MRI scan while two stepwise CO2 elevations are applied to the participant by adding fractional concentration of inspired CO2 (FICO2) at 4% and 6% each time. The end tidal CO2 (PetCO2) will be elevated and maintained constant for a few minutes at each target level. Breath-by-breath changes in respiratory rate and PetCO2 will be measured.

TCDDEVICE

Participants will undergo a TCD scan while two stepwise CO2 elevations are applied to the participant by adding fractional concentration of inspired CO2 (FICO2) at 4% and 6% each time. The end tidal CO2 (PetCO2) will be elevated and maintained constant for a few minutes at each target level. Breath-by-breath changes in respiratory and PetCO2 will be measured.

Eligibility

Sex: ALLMin age: 20 YearsMax age: 64 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Between 20-34 or 50-69 years * Body mass index \<34 kg/m2 Exclusion Criteria: * Current smoker * History or evidence of: hepatic disease, renal disease, hematological disease, peripheral vascular disease, stroke/neurovascular disease, diabetes, hypertension * Part of a vulnerable population (e.g. pregnant women, prisoner, individuals lacking capacity to consent, etc.) * Older females only: subject is not post-menopausal

Locations (1)

University of Wisconsin-Madison

Madison, Wisconsin, United States

Outcomes

Primary Outcomes

Middle Cerebral Artery Blood Flow Measurement

Utilize the TCD and MR imaging to measure middle cerebral artery blood flow in the brain while the participant is at rest.

Time frame: 75 minutes

Middle Cerebral Artery Blood Flow Reactivity to Hypercapnia

Utilize the TCD and MR imaging to measure middle cerebral artery blood flow reactivity to hypercapnic gas.

Time frame: 75 minutes

Data from ClinicalTrials.gov

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