The elastic constant of tissue in the body estimated from computerized tomography and ultrasonography--theoretical analysis.

This paper describes a method for calculating the elastic constant of tissue. Length measurements obtained from Ultrasonograms (US) are different from the results obtained from Computerized Tomograms (CT) when the velocity of sound is compared to standardized water measurements. The density of tissue PI can be approximated by the equation. p, = 1N</N,;•. where N, and N". are the CTvalues of tissue and air respectively. The elastic constant (bulk modulus) K,. sound velocity Y, and density PI are related through the following equation, Y= (K./ PI)O.,. The elastic constant K, is then calculated by, K, = Kw (L,j L,)2. (I N</ N,;.), where Kw is the bulk modulus of water, and L, and L, are the measured distances from CT and US images respectively.