Abstract: Techniques for performing an acoustic rheology measurement of a sample are provided. A first set of acoustic pulses is provided by a focused ultrasound transducer to induce surface oscillations of the sample. A second set of acoustic pulses is provided by a detection transducer to interrogate the sample and detect the echo pulses reflected by the sample surface as a function of time. The detection ultrasound transducer system converts the echo signals to an electrical signal associated with the detected echo pulses, and a processor determines a dynamic displacement of the interface of the sample as a function of time. The processor also determines the spectrum, resonant surface oscillation frequency, and damping coefficient. Viscoelastic properties of the material are determined from these measurements, with applications for the characterization of the blood clotting process, the identification of a blood clot, gelation process, tumor, or fibrosis based on the viscoelastic properties.

Abstract: A new acoustic technique, tensile acoustic rheometry (TAR) for performing rheology measurement of a soft viscoelastic material sample is provided. In TAR, an excitation acoustic pulse is applied using a focused ultrasound transducer to a sample material to induce oscillatory motion of the sample. To track this induced motion, high repetition frequency ultrasound pulse-echo technique is used using a co-linear, con-focal ultrasound transducer that detects the backscattered echo signal from a surface or an interface of the sample. The detection ultrasound transducer system converts the echo signals to an electrical signal, and a processor determines a displacement of the interface of the sample as a function of time. The processor also determines the spectrogram, or the frequency spectrum of the dynamic surface movement of the sample material as a function of the time. Viscoelastic properties of the material are then determined from the displacement and the spectrogram measurements.

Abstract: A new acoustic technique, tensile acoustic rheometry (TAR) for performing rheology measurement of a soft viscoelastic material sample is provided. In TAR, an excitation acoustic pulse is applied using a focused ultrasound transducer to a sample material to induce oscillatory motion of the sample. To track this induced motion, high repetition frequency ultrasound pulse-echo technique is used using a co-linear, con-focal ultrasound transducer that detects the backscattered echo signal from a surface or an interface of the sample. The detection ultrasound transducer system converts the echo signals to an electrical signal, and a processor determines a displacement of the interface of the sample as a function of time. The processor also determines the spectrogram, or the frequency spectrum of the dynamic surface movement of the sample material as a function of the time. Viscoelastic properties of the material are then determined from the displacement and the spectrogram measurements.

Abstract: Techniques for performing an acoustic rheology measurement of a sample are provided. A first set of acoustic pulses is provided by a focused ultrasound transducer to induce surface oscillations of the sample. A second set of acoustic pulses is provided by a detection transducer to interrogate the sample and detect the echo pulses reflected by the sample surface as a function of time. The detection ultrasound transducer system converts the echo signals to an electrical signal associated with the detected echo pulses, and a processor determines a dynamic displacement of the interface of the sample as a function of time. The processor also determines the spectrum, resonant surface oscillation frequency, and damping coefficient. Viscoelastic properties of the material are determined from these measurements, with applications for the characterization of the blood clotting process, the identification of a blood clot, gelation process, tumor, or fibrosis based on the viscoelastic properties.