Method of displaying an elastic image

A method of displaying an elastic image, comprising:

• a) performing transmission/reception of an ultrasound signal along a plurality of scan lines set on a target object to obtain first ultrasound data, the target object including a plurality of tissues;
• b) performing transmission/reception of an ultrasound signal along a plurality of scan lines set on the target object while applying stress to the target object to obtain second ultrasound data;
• c) calculating, with a processor, displacements of the tissues at the respective scan lines based on the first and second ultrasound data;
• d) calculating, with a processor, strains at the respective scan lines based on the calculated displacements and average strains of the strains for the respective scan lines;
• e) forming an elastic image based on the calculated strains and a graph indicating the average strains at the respective scan lines;
• and
• f) displaying the elastic image together with the graph.