TIME-DOMAIN ULTRASONIC CONTRAST BLOOD FLOWMETRY

Time-domain ultrasonic blood flow estimation methods have recently rec eived considerable attention because of their advantages over conventi onal Doppler methods. Among them are that they may yield better spatia l resolution and that methods based on frame-to-frame speckle tracking do not require a knowledge of the angle between directions of blood f low and the ultrasound beam. These methods, however, suffer from an in trinsic problem of poor signal-to-noise ratio, since the echoes scatte red back by blood are much weaker than those of the surrounding struct ures. In addition, the maximal velocity that can be estimated by frame -to-frame tracking via conventional ultrasonic scanners is limited by the frame rate of the scanner. In this article, we will present experi mental results to show that these problems may be alleviated by using a high frame rate scanner in conjunction with the injection of an ultr asonic contrast agent. In this study the contrast agent used was Albun ex(R).