Ultrasonograph that determines tissue properties utilizing a reference waveform

An ultrasonic diagnostic apparatus comprising:

• a transmitting section that generates a drive signal to drive a probe in order to transmit an ultrasonic wave toward a subject to be deformed periodically under stress;
• a receiving section for receiving an echo, produced when the ultrasonic wave is reflected from the subject, at the probe to generate a received echo signal;
• a computing section for figuring out a thickness change waveform, representing a variation in distance between two arbitrary measuring points on the subject, based on the received echo signal;
• a reference waveform generating section for outputting a reference waveform;
• and
• a thickness change estimating section for calculating a coefficient to be multiplied by either the thickness change waveform or the reference waveform so as to minimize a matching error between the thickness change waveform and the reference waveform and for calculating the greatest variation in the thickness change waveform based on the coefficient and the amplitude of the reference waveform,
• wherein the reference waveform is generated by calculating the average of thickness change waveforms that have been collected in advance from a plurality of subjects, or is generated based on either a displacement waveform representing a displacement of a measuring point on the subject, a waveform representing a variation in the vascular caliber of the subject, or a waveform representing a variation in the blood pressure of the subject.