ABSTRACT
During the past 50 years, ultrasound has developed into a widely used research and clinical modality with its most widespread and familiar applications in noninvasive two-dimensional and color Doppler imaging.1-4 From its earliest days, ultrasound has found nonimaging medical applications using noninvasive as well as invasive, intraoperative, implantable, and intravascular transducers and sensors to measure dimensions, displacement, velocity, and ow. Here, we will concentrate on the ultrasonic measurement of blood ow and velocity.
