Analysis of Ultrasonic Blood Rheogram by the Sound Spectrograph

Abstract

The flow patterns were recorded in the basic study by means of the ultrasonic blood rheograph with the sound spectrograph analyzing method which had been developed in our laboratory. The results were summarized as follows : 1) Flow volume can be measured quantitatively only when the cross-sectional area of the flow is measured, and when the ultrasonic incident angle is smaller than 70° and the pulse rate is not so large. 2) Flow pattern was constant regardless of the distance between the flow sensor and the flow or of the shift of the flow sensor out of the center-line of the flow. 3) Effect of the change of the ultrasonic incident angle on the flow pattern can be neglected under the proper normalization. 4) A linear correlation was proved between the mean maximum flow velocity and the true flow volume when the cross-sectional area of the flow is constant at the measuring point. Moreover, the values of the maximum flow velocity of the carotid flow from young normal subjects were standardized at several characteristic points in a cardiac cycle. The maximum velocity waves were analyzed by the Fourier transform and evaluated. These hemodynamical indices, i.e., the mean maximum flow velocity A/L value, the elasticity index EUSR and the resistance index RUSR were presented and standardized by the application to the carotid and vertebral flows.