Improved analysis of brachial artery ultrasound using a novel edge-detection software system

• Published in: Journal of applied physiology (1985) Vol. 91; no. 2; pp. 929 - 937
• Main Authors: Woodman, R. J, Playford, D. A, Watts, G. F, Cheetham, C, Reed, C, Taylor, R. R, Puddey, I. B, Beilin, L. J, Burke, V, Mori, T. A, Green, D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.08.2001; American Physiological Society
• Subjects: Analysis of Variance; Biological and medical sciences; Blood Pressure; Blood vessels; Blood vessels and receptors; Brachial Artery - diagnostic imaging; Brachial Artery - physiology; Calibration; Computer Graphics; Electrocardiography; Endothelium, Vascular - diagnostic imaging; Endothelium, Vascular - physiology; Fundamental and applied biological sciences. Psychology; Humans; Lipids - blood; Lungs; Middle Aged; Nitroglycerin - pharmacology; Observer Variation; Phantoms, Imaging; Reference Values; Reproducibility of Results; Software; Ultrasonic imaging; Ultrasonography; Vasodilation - drug effects; Vasodilation - physiology; Vertebrates: cardiovascular system; Videotape Recording; Sonography; High resolution; Brachial artery; Endothelium; Vertebrata; Mammalia; Blood vessel; Non invasive method; Circulatory system; Vascular wall; Edge detection; Computer aid; Diameter
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2001.91.2.929

Departments of 1  Medicine and 2  Human Movement and Exercise Science, The University of Western Australia, Perth 6001; and Departments of 4  Cardiology and 3  Medical Physics, The West Australian Heart Research Institute Royal Perth Hospital, Perth 6000, Western Australia, Australia Brachial artery ultrasound is commonly employed for noninvasive assessment of endothelial function. However, analysis is observer dependent and susceptible to errors. We describe studies on a computerized edge-detection and wall-tracking software program to allow more accurate and reproducible measurement. In study 1 , three purpose-built Perspex phantom arteries, 3.00, 4.00, and 6.00 mm in diameter, were measured with the software. There was a mean bias of 11 µm ( P  < 0.001 at each level) between known and measured values; the mean resolving power of the software was estimated as 8.3 µm. In study 2 , the mean intraobserver coefficient of variation of repeated measures of flow-mediated dilation (FMD) using the software (6.7%) was significantly lower than that for traditional manual measurements using the intima-lumen interfaces (24.8%, P  < 0.05) and intima-media interfaces (32.5%, P  < 0.05). In study 3 , 24 healthy volunteers underwent repeat testing twice within 1 wk; the coefficients of variation for between-visit reproducibility of FMD and response to glyceryl trinitrate using the software were 14.7 and 17.6%, respectively. Assuming 80% power and an   of 0.05, eight subjects with matched controls would be required, in a parallel designed study, to detect an absolute 2.5% change in FMD. In summary, we have developed a semiautomated computerized vascular ultrasound analysis system that will improve the power of clinical intervention studies to detect small changes in arterial diameter. flow-mediated dilation; glyceryl trinitrate; high-resolution ultrasound; wall tracking