ULTRASONIC MEASUREMENT OF FORCED DIAMETER VARIATIONS IN AN ELASTIC TUBE

This paper presents an ultrasonic measurement technique to determine a n elasticity parameter, called the apparent compliance, in a thin-wall ed tube. The apparent compliance is obtained by ultrasound pulse-echo measurement of the diameter variation in response to an externally app lied time-varying pressure function. Specifically, the diameter variat ion is obtained by tracking the time shift of the echoes from the fron t and back walls of the tube using a correlation technique. This techn ique is named the Forced Vibration Method (FVM). This approach to comp liance measurement is distinctly different from compliance measurement s using the blood function as excitation function, but is closely rela ted to the elastic imaging concept. Two experimental models, termed th e rigid wall model and the leg-like model, have been developed. These models allow the amplitude and frequency of the pressure function as w ell as the dimensions and properties of the tube to be varied. Results for the diameter variations vs. location along the tube and frequency of external pressure function are presented for both models. (C) 1994 Academic Press, Inc.