The purpose of this research is assess imaging and identification of soft plaque that undergoes large deformations or strain will identify plaque vulnerable to rupture which could lead to 'silent strokes'. Validation of current study results with MRI will foster use of real-time ultrasound (US) strain imaging and strain indices as a screening tool for identifying normal human participants susceptible to increased vascular aging and developing plaque prone to rupture or micro-embolization. Current research will evaluate Lagrangian carotid strain imaging (LCSI) for prediction of vascular health on volunteers. In this study, investigators will evaluate age-related strain variations (due to plaque deposition) in the carotid artery, establishing groundwork that will help identify typical and atypical values for these indices. Investigator's hypothesis is that plaques with higher strain indices (softer plaques) are more prone to rupture than plaques with lower strain indices (stiffer) plaques, thus requiring intervention. Clinical criteria for treatment has focused primarily on the degree of stenosis. Long-term objectives are to provide non-invasive methods for screening participants at risk for vascular aging or plaque rupture in asymptomatic participants, expanding upon current criteria for risk assessments based on focal transient ischemic attack (TIA) or strokes. Variations in vessel strain have been associated with, or are precursors to, plaque deposition, vascular aging, or cerebrovascular diseases. Increased arterial strain and pressure changes have been linked to brain aging using magnetic resonance imaging (MRI) based vascular indices, and memory deficits commonly linked to Alzheimer dementia. Stiffening and thickening of the arterial walls have also been associated with cerebrovascular disease. Investigators hypothesize that strain indices as vascular biomarkers can be utilized for screening possible 'vulnerable participants' validated with MRI, with the potential ability to improve endothelial function and reverse vascular aging. Strain indices may enable differentiating study participants with vascular cognitive impairment (VCI) from other dementias. Cognitive testing is unable to make this differentiation.
Study Type
OBSERVATIONAL
Enrollment
217
Carotid artery ultrasound exam. US imaging will include complete clinical carotid ultrasound examination (B-mode, Doppler and color-flow modes), clinical strain and shear wave imaging study, backscattered and beam-steered radiofrequency (RF) data acquisition using research mode, and reference phantom RF data acquisition.
Head and Neck MRI exam with contrast
Harmonization battery to assess executive function/attention, speeded psychomotor, verbal, and nonverbal memory, language, and visuospatial skills
Use of a TCD system to monitor right and left middle cerebral artery Doppler waveforms in the volunteer for 60 minutes
Pulse wave Doppler will be used to acquire a Doppler waveform in the right common carotid artery and the right femoral artery
Department of Medical Physics, University of Wisconsin
Madison, Wisconsin, United States
Characterization of artery wall stiffness and possible plaque by capturing B-mode, Doppler and color-flow modes of Ultrasound
Participants will receive complete clinical carotid ultrasound examination. B-mode, Doppler and color-flow modes of Ultrasound will be captured. This measure will characterize artery wall stiffness and possible plaque by using Ultrasound.
Time frame: up to 60 minute
Characterization of artery wall stiffness and possible plaque by using radiofrequency ultrasound signals to estimate strain tensors, pulse wave velocity (PWV), and shear wave imaging
Participants will receive complete clinical carotid ultrasound examination. Clinical strain and shear wave imaging will be performed. This measure will characterize artery wall stiffness and possible plaque by using Ultrasound.
Time frame: up to 60 minute
Carotid artery ultrasound examination for Aim-1 participants: backscattered and beam-steered RF data acquisition using research mode
Participants will receive complete clinical carotid ultrasound examination. Backscattered and beam-steered RF data acquisition using research mode, and reference phantom RF data acquisition will be performed. This measure will characterize artery wall stiffness and possible plaque by using Ultrasound.
Time frame: up to 60 minute
Fasting Lipid panel Analysis
For aim-1 participants, a single fasting (10-12 hours) blood sample will be collected for a fasting lipid panel
Time frame: up to 13 hours
Hemoglobin A1C test for diabetes
For aim-1 participants, a single fasting (10-12 hours) blood sample will be collected for a Hemoglobin A1C test
Time frame: up to 13 hours
High-sensitivity C-reactive protein (HS-CRP) test for inflammatory markers for Aim 1 participants
For aim-1 participants, a single fasting (10-12 hours) blood sample will be collected for High-sensitivity C-reactive protein (HS-CRP) test
Time frame: up to 13 hours
Detection of Plaques by MRI- Accuracy of MRI detection method as compared to Ultrasound and blood work
Longitudinal Ultrasound strain and MRI study will be performed on on a sub-group of 40(aim-2) at risk participants determined from the clinical ultrasound scans and bloodwork from Aim 1. This subgroup meet the criteria for being in a higher risk group for atherosclerosis or those with softer lipid-rich plaque (hypoechogenic or lower brightness on ultrasound). Participants will be contacted on the phone to discuss these incidental findings and to request if they would be interested in participating in follow-up MRI, US and strain. MRI results will be compared to previous Ultrasound and blood work results to test the accuracy of MRI method in detecting plaques.
Time frame: up to 60 minute
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