Abstract

By transmitting ultrasonic waves along a section of an object under examination, brightness modulating reflected ultrasonic waves from respective points in the section to obtain a B-mode tomography image, and displaying Doppler shifted frequencies of the reflected ultrasonic waves from the respective points in the tomography image in colors, a Doppler flow mapping image indicating blood flow two-dimensionally can be obtained. Also, by transmitting ultrasonic waves many times only in the direction of a desired observation point and analyzing the spectrum of Doppler shifted frequencies of reflected ultrasonic waves from the observation point, a blood flow pattern waveform indicating time-varying blood flow velocity can be obtained. In an ultrasonic diagnostic apparatus which transmits ultrasonic waves repeatedly to a subject under examination at regular intervals and detecting Doppler shifts of reflected ultrasonic waves to obtain the Doppler flow mapping image and the blood flow pattern waveform, by transmitting ultrasonic waves alternately in the direction needed to prepare the Doppler flow mapping image and in the direction needed to prepare the blood flow pattern waveform at each time of transmission of ultrasonic waves, the Doppler flow mapping image and the blood flow pattern waveform can be displayed simultaneously while improving detectable low velocity in the Doppler flow mapping image without degrading aliasing velocity in the blood flow pattern waveform.