Hybrid elastography Method, probe and device for hybrid elastography

A hybrid elastography method, comprising:

• applying, using a first vibrator comprised in a probe in contact with a viscoelastic medium, a continuous low frequency vibration and generating, using an ultrasonic transducer in contact with the viscoelastic medium, a first series of ultrasonic acquisitions, said first series of ultrasonic acquisitions including groups of ultrasonic acquisitions, the groups of ultrasonic acquisitions being generated with a first repetition rate, each group of ultrasonic acquisitions including at least one acquisition, the continuous low frequency vibration generating an elastic wave within the viscoelastic medium;
• determining, from the first series of ultrasonic acquisitions, at least one property of the elastic wave within the viscoelastic medium, the property of the elastic wave within the viscoelastic medium being used to compute a real time positioning indicator of the probe with respect to the viscoelastic medium to study;
• applying, using a second vibrator comprised in the probe in contact with the viscoelastic medium, a low frequency pulse and generating, using the ultrasonic transducer, a second series of ultrasonic acquisitions, the ultrasonic acquisitions composing the second series being generated with a second repetition rate, the low frequency pulse generating a transient shear wave propagating within the viscoelastic medium,
• wherein an amplitude of the low frequency pulse is determined on the basis of the properties of the elastic wave generated within the viscoelastic medium by the continuous low frequency vibration.

A hybrid elastography method, comprising:

• applying, using a first vibrator comprised in a probe in contact with a viscoelastic medium, a continuous low frequency vibration and generating, using an ultrasonic transducer in contact with the viscoelastic medium, a first series of ultrasonic acquisitions, said first series of ultrasonic acquisitions including groups of ultrasonic acquisitions, the groups of ultrasonic acquisitions being generated with a first repetition rate, each group of ultrasonic acquisitions including at least one acquisition, the continuous low frequency vibration generating an elastic wave within the viscoelastic medium;
• determining, from the first series of ultrasonic acquisitions, at least one property of the elastic wave within the viscoelastic medium, the property of the elastic wave within the viscoelastic medium being used to compute a real time positioning indicator of the probe with respect to the viscoelastic medium to study;
• applying, using a second vibrator comprised in the probe in contact with the viscoelastic medium, a low frequency pulse and generating, using the ultrasonic transducer, a second series of ultrasonic acquisitions, the ultrasonic acquisitions composing the second series being generated with a second repetition rate, the low frequency pulse generating a transient shear wave propagating within the viscoelastic medium,
• wherein the continuous low frequency vibration applied by the first vibrator is stopped before the applying of the low frequency pulse by the second vibrator and the generating of the second series of ultrasonic acquisitions, and
• wherein the stopping of the continuous vibration of the vibrator and the application of the low frequency pulse are separated by a time interval greater than 10 ms.

A hybrid elastography probe comprising:

• a first vibrator configured to apply to a viscoelastic medium a continuous low frequency vibration, the continuous low frequency vibration generating an elastic wave within the viscoelastic medium;
• a second vibrator configured to apply to the viscoelastic medium a low frequency pulse generating a transient shear wave within the viscoelastic medium;
• an ultrasonic transducer configured to emit:
• a first series of ultrasonic acquisitions concomitantly with application of the continuous low frequency vibration by the first vibrator, said first series of ultrasonic acquisitions including groups of ultrasonic acquisitions, the groups of ultrasonic acquisitions being generated with a first repetition rate, each group of ultrasonic acquisitions including at least one acquisition;
• a second series of ultrasonic acquisitions, the ultrasonic acquisitions composing the second series being generated with a second repetition rate;
• said probe further being configured to stop the application of the continuous vibration before the application of the low frequency pulse.