Validation of an automated method for assessing brachial artery endothelial dysfunction.
BACKGROUND
Endothelial dysfunction is an early finding in diverse vascular diseases and can be measured noninvasively using brachial ultrasound. There is great interest in the potential use of this parameter for assessing interventions or cardiovascular prognosis. Automated image analysis of the ultrasound images would facilitate implementation of such measurements in high throughput clinics and/or large clinical trials.


OBJECTIVE
To compare a new method designed to assess brachial artery diameter and percentage diameter changes through automated, beat-by-beat image processing (Brachial Tools, Medical Imaging Applications, USA), with a nonautomated method (Prosound System, Jet Propulsion Laboratory, USA).


METHODS
Brachial ultrasound tapes from 12 patients undergoing endothelial function assessment using forearm cuff-occlusion, measurement of flow-mediated dilation and responses to nitroglycerin were analyzed by both methods.


RESULTS
The correlation between the two systems was excellent for both the measurement of absolute diameters (r=0.995, P<0.001) and percentage diameter changes (r=0.973, P<0.001). The automated method demonstrated no bias compared with the frame-by-frame method and excellent precision (0.07 mm and 1.62 percentage diameter change).


CONCLUSIONS
The automated method provides valid data while substantially diminishing analysis time.
Mancini
G B John
GB
Cardiac Imaging Research Laboratory, Jack Bell Research Centre, Atherosclerosis Reversal Clinic, St Paul's Hospital, University of British Columbia, Vancouver. mancini@interchange.ubc.ca
Yeoh
Eunice
E
Abbott
David
D
Chan
Sammy
S
D000328:Adult; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D005996:Nitroglycerin / Q000494:pharmacology; D013223:Statistics as Topic; D014463:Ultrasonography; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D005996:Nitroglycerin