Honors Theses

Date of Award

Spring 5-12-2024

Document Type

Undergraduate Thesis

Department

Health, Exercise Science, and Recreation Management

First Advisor

Matthew Jessee

Second Advisor

John Bentley

Third Advisor

Jeremy Loenneke

Relational Format

Dissertation/Thesis

Abstract

Ultrasonographic flow-mediated dilation (FMD) is typically imaged longitudinally (LONG); however, it may be less reproducible compared to cross-sectional (CSA) imaging. We compared reproducibility of artery size between LONG and CSA across two experiments.

For experiment 1, a phantom artery was imaged in both views with no (NP), light (LP), and moderate (MP) pressures. At NP, for both views 2 images were obtained at 0o, 5o, 10o, and 15o probe tilt. This was repeated on 2 separate days. Artery areas (cm2) for each pressure and tilt were compared between views. Experiment 2 data was collected on human subjects using a within-subject design (2 identical visits). Participants lay supine, right arm extended, with an inflatable cuff on the forearm. After a 15-minute rest (arterial occlusion pressure measured at minute 5), the FMD protocol began using either CSA or LONG (randomized). Images were obtained from video recordings of the brachial artery with B mode ultrasound across a 2-minute baseline, 5-minute cuff inflation, and 5-minute post-deflation period. After 30 minutes, this was repeated in the same arm using view 2. Change in artery size from baseline to peak post-deflation was calculated to determine individual FMD responses. RESULTS. Experiment 1: Artery sizes (cm2) in LONG across both days for NP, LP, and MP were 0.243, 0.214, and 0.177, respectively. For CSA, 0.218, 0.198, and 0.182, respectively. Artery sizes in LONG were 0.204, 0.205, 0.191, and 0.162, for 0o, 5o, 10o, and 15o, respectively. For CSA, 0.205, 0.209, 0.212, and 0.239 for 0o, 5o, 10o, and 15o, respectively. Experiment 2: 20 participants (f=10) average age 24.85 (yrs), height 170.41(cm), and weight 69.12(kg). The average FMD response (mm2) from visits 1 and 2 was 1.06 and 1.22 for LONG and 1.21 and 1.62 for CSA. The mean absolute difference in FMD values between visits 1 and 2 for LONG and CSA were 0.54 and 0.77, respectively. A Bayesian dependent t-test between absolute differences across methods yielded anecdotal evidence for the null hypothesis (BF10=0.725).

CONCLUSION. Experiment 1 indicates LONG measurements may be influenced by probe pressure and tilt more than CSA. Experiment 2 data suggests no difference in agreement between views. Further research is needed to determine which view produces more agreeable values across different measurement days before fully implementing the CSA method of measurement.

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Available for download on Thursday, April 29, 2027

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