A NEW WIDE-BAND SPREAD TARGET MAXIMUM-LIKELIHOOD ESTIMATOR FOR BLOOD VELOCITY ESTIMATION .2. EVALUATION OF ESTIMATORS WITH EXPERIMENTAL-DATA

Part I of the work presented the derivation and theoretical evaluation of new wideband maximum likelihood strategies for the estimation of blood velocity using acoustic signals. In Part II, the signal models and performance of the estimation strategies described in Part l are tested with experimental ultrasonic data. The ultrasonic data analyzed in the work verifies the theoretical model and predicted performance. The averaged correlation, verified experimentally, confirms that the corellation envelope can be used to estimate the velocity of scatterers, and that the shape of the correlation function conveys information regarding the velocity profile within the sample volume. For both the wideband point and range spread estimators, the predicted improvement in velocity resolution and the reduction in the height of subsidiary velocity peaks are demonstrated. Through the use of these estimation strategies, information regarding the mean velocity and velocity variation are available for each spatial location within the vessel. This information is presented using a three-dimensional (3-D) spatial velocity profile display, which appears to offer a number of advantages in the rapid identification of pathology.