Ultrasonic diagnosis apparatus

Abstract

A plurality of vibrating elements are provided to form an array and successive vibrating elements are selected to emit ultrasonic pulses toward a cavity of a living body. Ultrasonic waves reflected by tissues and blood cells in the blood vessel are received by the vibrating elements and are converted into echo signals. The echo signals are supplied to an orthogonal detector together with a reference signal and are converted into real and imaginary parts of complex signals which are stored in memories as the wave surface data. The wave surface data is read out at suitable timings to obtain an ultrasonic reflection image data such that a focus point is formed in a given space. By processing the reflection image data by a spectrum distribution detector, a spatial frequency is derived. A reflection strength is derived from a DC component of the spatial frequency and a B-mode ultrasonic image is displayed. From an AC component of the spatial frequency a velocity and a direction of a blood stream are derived and are displayed in superimposition with the B-mode ultrasonic image. In this manner, it is possible to detect accurately a blood stream having a very low velocity. Also a blood stream flowing in a direction parallel with a direction in which the vibrating elements are arranged can be measured.