Doctoral Defense - Josh Hubert

About the Event

The Department of Biomedical Engineering

Michigan State University

Ph.D. Dissertation Defense

March 31, 2025 at 1:30pm EST

1404 ISTB Building and Zoom

Contact Department or Advisor for Zoom Information

ABSTRACT

EXAMINATION OF CEREBRAL BLOOD FLOW AND CEREBROSPINAL FLUID DYNAMICS
IN HYPERTENSIVE OLDER ADULTS WITH BLOOD PRESSURE MANAGEMENT AND
POTENTIAL RELATIONSHIP WITH CEREBRAL VASCULAR TISSUE DAMAGE

By: Josh Hubert

Advisor: David Zhu

Recent research has implicated vascular dysfunction as a significant contributor to Alzheimer’s Disease onset and progression, with mid-life Hypertension (HT) being an important modifiable risk factor. One possible mechanism underlying this association is increased pulsatility of cerebral blood flow (CBF) in HT leading to small vessel disease, blood-brain barrier disruptions, and changes in cerebrospinal fluid (CSF) waste clearance. However, the effects of blood pressure management on cerebrovascular health and CSF flow are not fully understood. Two non-invasive imaging techniques, Phase-Contrast Magnetic Resonance Imaging (PC MRI) and T2-Weighted Fluid-Attenuated Inversion Recovery (FLAIR), allow us to measure CBF, CSF flow, and biomarkers of small vessel disease called White Matter Hyperintensities (WMH). These tools may provide insights into the effectiveness of blood pressure management on cerebral vascular and tissue health.

CBF and CSF flow parameters were examined in normotensive adults, HT adults, and HTadults after 1 year of blood pressure management using PC MRI. Estimations of pressure gradients in CSF pathways using a computational model were also explored. Adults with HT had higher vessel pulsatility, lower diastolic CBF, and higher spinal CSF pressure gradients that were not significantly affected by blood pressure management. Also, five novel algorithms for WMH segmentation were evaluated against two widely used classical algorithms using 714 FLAIR images from three large datasets, with data acquired across 7 different sites and 10 different scanners. The resulting volumetric WMH measurements from the top performer, PGS, showed significantly positive correlations to blood pressure measurements and age, but further work is needed for longitudinal comparisons.

Persons with disabilities have the right to request and receive reasonable accommodation. Please call the Department of Biomedical Engineering at 884-6976 at least one day
prior to the seminar; requests received after this date will be met when possible.