title: Simultaneous ultrasound assessment of brachial artery shear stimulus and flow-mediated dilation during reactive hyperemia.
abstract: In flow-mediated dilation (FMD) studies, brachial artery diameter changes due to reactive hyperaemia are typically measured through manual or automatic analysis of high resolution B-mode images while the stimulus of diameter change, i.e., the flow change, is qualitatively estimated by measuring the mean velocity in the vessel and assuming a parabolic velocity profile. This article describes an experimental approach to simultaneously measure the wall shear rate (WSR) and the diameter variations, through multigate spectral Doppler and B-mode image processing, respectively. By using an ultrasound advanced open platform (ULA-OP), experimental results from the brachial arteries of 15 presumed healthy volunteers have been obtained. The mean increments during reflow against baseline were 105% ± 22% for the peak WSR and 8% ± 3% for the FMD. The mean time interval between the WSR peak and the beginning of plateau of diameter waveform was 38 ± 8 s. The results confirm that in young healthy subjects the postischemic vasodilation of brachial artery is largely correlated to the WSR increase.
authors.affiliation: Department of Electronics and Telecommunications, Università degli Studi di Firenze, Firenze, Italy. piero.tortoli@unifi.it
authors.forename: Piero
authors.initials: P
authors.lastname: Tortoli
authors.forename: Carlo
authors.initials: C
authors.lastname: Palombo
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Ghiadoni
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Francalanci
mesh_terms: D000328:Adult; D000465:Algorithms; D001783:Blood Flow Velocity; D001916:Brachial Artery / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D018608:Ultrasonography, Doppler; D014664:Vasodilation / Q000502:physiology