Patent ID: 7569016

Claim:
An ultrasonic diagnostic apparatus, comprising: transmission means for transmitting at least one ultrasonic signal from a surface of a skin of a subject toward a blood vessel of the subject; reception means for receiving an ultrasonic echo reflected by the blood vessel and converting the ultrasonic echo into an electric signal to obtain the ultrasonic echo signal in a depth direction from the surface of the skin; movement detection means for analyzing a phase of the ultrasonic echo signal in a direction traversing the blood vessel to calculate a movement amount of a blood vessel wall composing the blood vessel; analysis means for analyzing a state of the blood vessel based on a difference of a track of movement of the blood vessel wall whose movement amount was calculated with respect to time; boundary position detection means for detecting a boundary position between a blood flow region and the blood vessel wall of the blood vessel based on a result of the analysis by the analysis means; and stability judgment means for comparing the boundary position detected by the boundary position detection means with a detection result in a previous heartbeat cycle, thereby judging stability of a measurement state.