P2E-4 Transient Ultrasound Radiation Force Elastography. Preliminary Comparison with Surface Palpation Elastography

The use of impulsive acoustic radiation force for transient strain imaging was investigated. A series of experiments were performed in order to evaluate the performances of the technique on gelatin phantoms containing inclusions and to determine a range of applications where radiation force elastography may be useful compared with static elastography. Inside the gelatin phantoms slip boundaries, soft and stiff inclusions were placed. A focused ultrasound transducer was used to apply localised radiation force to a small volume of tissue mimic (100 mm³) for durations of 8 ms. A conventional real-time ultrasound imaging probe was used to obtain radio frequency echo signals. The resulting strains were mapped using ultrasound correlation-based methods. The instantaneous strain immediately following cessation of the radiation force was observed at depth within inhomogeneous gels. The highly localized and transient strain that is produced at depth permits the sensing of variations in tissue elastic properties that are difficult to detect with conventional elastography, due to greater independence from boundary conditions