US 9,168,021 B2Granted

Method and apparatus for measuring heart contractility

AssigneesSuper Sonic Imagine, Centre National de la Recherche Scientifique (CNRS)

InventorsMathieu Pernot, Mickaël Tanter, Mathieu Couade, Mathias Fink

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Abstract

A Method for measuring heart contractility of a patient, in which a mechanical shear wave is propagated through the heart and observation of the propagation leads to determine a shear wave propagation parameter representative of the elasticity of the heart is disclosed. The value of the propagation parameter at the end of a systole is sampled, which leads to a parameter representative of the end systolic elastance.

Claims15

Dependent claims

A Method for measuring heart muscle contractility of a patient, comprising at least the following steps:

a) an excitation step during which an elastic shear wave is generated in the patient's heart muscle by causing at least one focused ultrasound wave to be emitted into the patient's body by an array of transducers;
b) an observation step during which the propagation of the shear wave is observed in an observation field in the patient's heart muscle, this observation step comprising the following substeps:
b1) causing the array of transducers to emit into the patient's heart muscle a succession of unfocused ultrasound compression waves, the timing of said unfocused ultrasound waves being adapted so that at least some of said unfocused ultrasound waves penetrate into the observation field while the shear wave is propagating in the observation field;
and
b2) causing sound signals received from said observation field to be detected in real time by said array of transducers, said sound signals comprising echoes generated by the unfocused ultrasound compression waves interacting with reflecting particles in the patient's heart muscle;
and
c) a processing step including a substep in which at least one movement parameter is determined in the observation field, said movement parameter characterizing movements of said reflecting particles;
and
d) a heart contractility estimating step in which, based on variation in the movement parameter over time, values of said shear wave propagation parameter are determined repeatedly at several different instants, several times per second over a measuring period covering at least one cardiac cycle and at least an end-systolic elasticity parameter is determined at at least one point of the observation field on the basis of said values of said shear wave propagation parameter, said shear wave propagation parameter being representative of the elasticity of the heart muscle, a maximum of said values of said shear wave propagation parameter is determined and said end-systolic elasticity parameter is determined as a function of said maximum, said end-systolic elasticity parameter corresponding to said heart contractility.

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Dependencies are inferred from the claim text.

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Abstract

A Method for measuring heart muscle contractility of a patient, comprising at least the following steps:

a) an excitation step during which an elastic shear wave is generated in the patient's heart muscle by causing at least one focused ultrasound wave to be emitted into the patient's body by an array of transducers;
b) an observation step during which the propagation of the shear wave is observed in an observation field in the patient's heart muscle, this observation step comprising the following substeps:
b1) causing the array of transducers to emit into the patient's heart muscle a succession of unfocused ultrasound compression waves, the timing of said unfocused ultrasound waves being adapted so that at least some of said unfocused ultrasound waves penetrate into the observation field while the shear wave is propagating in the observation field;
and
b2) causing sound signals received from said observation field to be detected in real time by said array of transducers, said sound signals comprising echoes generated by the unfocused ultrasound compression waves interacting with reflecting particles in the patient's heart muscle;
and
c) a processing step including a substep in which at least one movement parameter is determined in the observation field, said movement parameter characterizing movements of said reflecting particles;
and
d) a heart contractility estimating step in which, based on variation in the movement parameter over time, values of said shear wave propagation parameter are determined repeatedly at several different instants, several times per second over a measuring period covering at least one cardiac cycle and at least an end-systolic elasticity parameter is determined at at least one point of the observation field on the basis of said values of said shear wave propagation parameter, said shear wave propagation parameter being representative of the elasticity of the heart muscle, a maximum of said values of said shear wave propagation parameter is determined and said end-systolic elasticity parameter is determined as a function of said maximum, said end-systolic elasticity parameter corresponding to said heart contractility.

6 more elements