title: Evaluating the use of a portable ultrasound machine to quantify intima-media thickness and flow-mediated dilation: agreement between measurements from two ultrasound machines.
abstract: Flow-mediated dilation (FMD) and common carotid intima-media thickness (CIMT) are intermediate endpoints for cardiovascular disease. The purpose of this study was to determine whether a portable ultrasound machine was capable of valid measurements of FMD and CIMT compared with a clinic-based machine under similar conditions. Vascular images were taken on 23 apparently healthy young adults with the portable type and clinic type instruments. The analyses revealed a high level of agreement between the two machines for measurements of mean [corrected] CIMT (mean difference [MD] = -0.025 mm, limits of agreement [LOA] = -0.080, 0.029 mm), maximum [corrected] CIMT (MD = 0.001 mm, LOA = -0.065, 0.065 mm) and FMD measures of brachial diameter (baseline MD = 0.199 mm, LOA = -0.210, 0.608 mm, maximum MD = 0.218 mm, LOA = -0.162, 0.597 mm). Reasonable agreement was found for %FMD measurements (MD = 0.27%, LOA = -4.91, 5.44%). The within-machine coefficient of variation results for mean [corrected] CIMT (5.0%), maximum [corrected] CIMT (4.3%), baseline (6.3%) and maximum (5.4%) brachial diameter and %FMD (30.1%) were comparable with normal within-subject variation. We conclude that the portable ultrasound machine can provide measurements of FMD and CIMT that are highly comparable with measurements obtained from a clinic-based machine under similar clinical conditions.
authors.affiliation: Menzies Research Institute, Hobart, Australia. cmagnuss@utas.edu.au
authors.forename: Costan G
authors.initials: CG
authors.lastname: Magnussen
authors.forename: Jayne
authors.initials: J
authors.lastname: Fryer
authors.forename: Alison
authors.initials: A
authors.lastname: Venn
authors.forename: Mia
authors.initials: M
authors.lastname: Laakkonen
authors.forename: Olli T
authors.initials: OT
authors.lastname: Raitakari
mesh_terms: D000328:Adult; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D001916:Brachial Artery / Q000000981:diagnostic imaging; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D019095:Point-of-Care Systems; D015203:Reproducibility of Results; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography; D014664:Vasodilation