Patent ID: 8052602

Claim:
An ultrasonic diagnostic apparatus for measuring a shape characteristic or a property characteristic of body tissue, comprising: a velocity calculator which calculates a motion velocity of the body tissue and a move displacement calculator which calculates a move displacement of the body tissue; a strain variation calculator which calculates a strain variation of the body tissue based on the motion velocity or the move displacement; a stress variation detector which detects a stress variation applied to the body tissue; a frequency analyzer which conducts frequency analysis on the motion velocity and the move displacement and determines a frequency of a power spectrum difference of the motion velocity and the move displacement between a plurality of different points of interest on the body tissue; a strain induced by stress and elastic wave separator which separates, approximately at the frequency as determined by the frequency analyzer, a strain induced by stress component based on motion of the body tissue caused by stress change of the body tissue motion and an elastic wave component based on an elastic wave propagation characteristic propagating in the body tissue, from the motion velocity, the move displacement, the strain variation, and the stress variation; and an elastic modulus calculator which calculates a compressive elastic modulus based on motion of the body tissue caused by stress change based on the strain variation and the stress variation, and also calculates at least one of shear elastic modulus and shear viscosity modulus based on the elastic wave propagation characteristic.