Brachial artery: measurement of flow-mediated dilatation with cross-sectional US--technical validation.

Ultrasonographic examination of flow phantoms and the brachial artery of a healthy volunteer undergoing reactive hyperemia was performed. Images were analyzed with a user-guided automated boundary detection (UGABD) algorithm to extract boundaries and measure cross-sectional area. UGABD correctly detected pulsatile vasomotion and measured area within 5% of the true value. A comparison of UGABD versus manual tracing yielded linear correlation of 0.81-0.91. Peak vasodilatation measured in response to reactive hyperemia was 150 times greater in pixel count than that measured with longitudinal imaging. Cross-sectional imaging is more sensitive than longitudinal imaging for measuring flow-mediated dilatation of the brachial artery.