US 5,495,771 A · Elasticity measuring method and elasticity measuring apparatus

Abstract

There are provided an elasticity measuring method of measuring an elastic constant of elasticity of an elastic body, for example, an elastic rubber, an organism or a living body, etc., which is soft and rather incompressible, by means of measuring an internal strain using energy such as ultrasounds, an X-ray, and magnetism, where the elastic constant includes, for example, typically shear modulus, Young's modulus, etc.; and an elasticity measuring apparatus adapted to practice such an elasticity measuring method. According to such method and apparatus, the elastic constant distribution within the subject is detected only through measuring the strain distribution within the subject, without measuring the stress distribution. The elasticity measuring method is of detecting the ratio of elastic value-to-elastic value, which are representative of levels of elasticity involved in a reference point on a predetermined straight line extending inside of a subject and a predetermined observation point on the straight line, respectively, by means of detecting the ratio of strain-to-strain, which are involved in said referencepoint and said observation point, respectively, with respect to a direction toward which the straight line extends.

Claims28

Dependent claims

An elasticity measuring method comprising the steps of:

generating and transmitting ultrasonic waves in a direction along a predetermined straight line extending inside of a subject having a surface;
receiving reflected ultrasonic waves to obtain a received ultrasonic signal;
detecting the ratio of elastic value of the surface-to-elastic value of inside of the subject, which is based on the received ultrasonic signal and which is representative of level of elasticity involved in a reference point on the predetermined straight line extending inside of the subject and a predetermined observation point on the straight line, respectively, by detecting the ratio of strain of the surface-to-strain of the inside of the subject, which is involved in said reference point and said observation point, respectively, with respect to the direction toward which the straight line extends,
wherein it is determined whether an absolute value of the strain on the observation point exceeds a predetermined threshold, and if the absolute value is less than the threshold, a predetermined value by which the ratio of strain of the surface-to-strain of the inside of the subject involved in said reference point and said observation point is replaced is associated with said observation point, instead of said ratio of strain of the surface-to-strain of the inside of the subject.

1 more element

An elasticity measuring method comprising the steps of:

generating and transmitting ultrasonic waves extending inside a subject;
receiving reflected ultrasonic waves to obtain a received ultrasonic signal;
detecting strains, based on the received ultrasonic signal, .epsilon..sub.xx (x,y), .epsilon..sub.xy (x,y), .epsilon..sub.yx (x,y) and .epsilon..sub.yy (x,y) as to points (x, y) on an arbitrary route C in a predetermined two-dimensional plane spreading within a subject from a reference point (A, B) up to a predetermined observation point (X,Y), and their associated differential coefficients .epsilon..sub.xx (x,y), .sub.x ;
.epsilon..sub.xx (x,y), .sub.y ;
.epsilon..sub.xy (x,y),.sub.x ;
.epsilon..sub.xy (x, y), .sub.y ;
.epsilon..sub.yy (x, y), .sub.x ;
.epsilon..sub.yy (x, y), .sub.y ;
and
detecting a curvilinear integral value on the route C from the reference point (A, B) up to the observation point (X,Y), where the curvilinear integral value is given by the following expression ##EQU22## whereby the ratio of elastic value-to-elastic value, which are representative of levels of elasticity involved in the reference point (A, B) and the observation point (X, Y), respectively, is detected.

7 more elements

An elasticity measuring method wherein a reference member, of which elastic value representative of a level of elasticity is known, is disposed on a reference point (A, B) in a predetermined two-dimensional plane spreading with a subject, said method comprising the steps of:

generating and transmitting ultrasonic waves extending inside the subject;
receiving reflected ultrasonic waves to obtain a received ultrasonic signal;
detecting strains, based on the received ultrasonic signal, .epsilon..sub.xx (x,y), .epsilon..sub.xy (x,y), .epsilon..sub.yx (x,y) and .epsilon..sub.yy (x,y) as to points (x, y) on an arbitrary route C in the two-dimensional plane from a reference point (A, B) up to a predetermined observation point (X,Y), and their associated differential coefficients .epsilon..sub.xx (x,y), .sub.x ;
.epsilon..sub.xx (x,y), .sub.y ;
.epsilon..sub.xy (x,y), .sub.x ;
.epsilon..sub.xy (x, y), .sub.y ;
.epsilon..sub.yy (x,y), .sub.x ;
.epsilon..sub.yy (x, y), .sub.y ;
detecting a curvilinear integral value on the route C from the reference point (A, B) up to the observation point (X,Y), the curvilinear integral value being given by the following expression;
and ##EQU23## detecting an elastic value on the observation point (X, Y) on the basis of both the integral value and the elastic value of said reference member.

7 more elements