Echogenicity from disturbed blood flow by an eccentric stenosis under pulsatile flow

Abstract

In order to investigate echogenicity from blood flow disturbance, a severe eccentric stenosis (∼70%) was constructed in a polystyrene tube (9.5-mm inner diameter) of a mock flow loop. A GE LOGIQ 700 Expert system was used to collect longitudinal and cross-sectional B-mode images from porcine whole blood. Harmonic, power, and color Doppler, and B-flow modes were also collected as references. Flow speed and stroke rate were controlled under pulsatile flow. The ‘‘black hole,’’ a hypoechoic zone at the center stream, was observed upstream of the stenosis during systole, while an expanding ‘‘bright ring’’ appeared during diastole in cross-sectional images. These rings looked like eddies due to backflow during diastole in longitudinal images. A bright stream line appeared from the orifice of the stenosis along the higher flow-speed zone during systole. A hyperechoic parabolic profile appeared once during a pulsatile cycle in longitudinal images showing the periodic spatial variation further downstream under some flow conditions. The parabolic profiles seemed to be a bright ring in cross-sectional images. Both longitudinal and cross-sectional images were helpful to understand 3D structures of echogenicity from disturbed blood flow by an eccentric stenosis under pulsatile flow.