Ultrasonic pulse inversion harmonic separation with reduced motional effects
AssigneeATL Ultrasound, Inc.
InventorsMichalakis Averkiou, Jeffry E. Powers
Life of this patent
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Abstract
Pulse inversion harmonic separation is performed utilizing echoes from three or more pulses of alternating phase or polarity. Temporally different echoes of opposite phase or polarity are combined in pairs, which are in turn combined to form partial sums and a final sum in which fundamental frequency signal components are substantially eliminated. Preferably the signals are normalized to a common reference level. The inventive technique can be performed by a filter structure using weighting coefficients exhibiting a Gaussian variation.
Claims30
A method for separating fundamental and harmonic components of an ultrasonic echo signal comprising the steps of:
- interrogating a sample volume with a sequence of four or more fundamental frequency transmit pulses of two differing phases or polarities;
- receiving a sequence of four or more temporally differing echoes of differing phases or polarities in response to said transmit pulses;
- and
- combining one set of pairs of echoes of differing phase or polarity to form a first partial sum of pairs of echoes;
- combining another set of pairs of echoes of differing phase or polarity to form a second partial sum of pairs of echoes;
- and
- utilizing said partial sums in a weighted combination to form separated harmonic signal components with reduced motional effects.
An ultrasonic diagnostic harmonic imaging system comprising:
- a transmitter which transmits fundamental frequency transmit pulses of two different phases or polarities to a substance in the body which may be moving;
- a receiver which receives temporally discrete echoes of different phases or polarities from said substance in response to said transmit pulses;
- a filter structure having inputs to which four or more of said temporally discrete echoes are applied, weighting coefficients for weighting said echoes, and a summer at which harmonic signals with reduced fundamental components are produced,
- wherein said weighting coefficients for a series of alternate phase or polarity echoes exhibit a sequence which increases from a low value to a high value, and decreases to a low value.
A method for separating harmonic components of an ultrasonic echo signal comprising the steps of:
- transmitting fundamental frequency transmit pulses of two different phases or polarities to a target location in the body which may be moving;
- receiving temporally discrete echoes of different phases or polarities from said target location in response to said transmit pulses;
- separating harmonic components of said echoes with a filter structure having inputs to which four or more of said temporally discrete echoes are applied, weighting coefficients for weighting said echoes, and a summer,
- wherein said weighting coefficients exhibit a sequence which increases from a low value to a high value and decreases to a low value so as to reduce motional effects in said separated components.
An ultrasonic diagnostic harmonic imaging system comprising:
- a transmitter which transmits fundamental frequency transmit pulses of two different phases or polarities to a substance in the body which may be moving;
- a receiver which receives temporally discrete echoes of different phases or polarities from said substance in response to said transmit pulses;
- a filter structure having inputs to which four or more of said temporally discrete echoes are applied, weighting coefficients for weighting said echoes, and a summer at which harmonic signals with reduced fundamental components are produced,
- wherein said weighting coefficients for a series of alternate phase or polarity echoes exhibit a sequence which increases from a low value to a high value.
An ultrasonic diagnostic harmonic imaging system comprising:
- a transmitter which transmits fundamental frequency transmit pulses of two different phases or polarities to a substance in the body which may be moving;
- a receiver which receives temporally discrete echoes of different phases or polarities from said substance in response to said transmit pulses;
- a filter structure having inputs to which four three or more of said temporally discrete echoes are applied, weighting coefficients for weighting said echoes, and a summer at which harmonic signals with reduced fundamental components are produced,
- wherein said weighting coefficients for a series of alternate phase or polarity echoes exhibit a sequence which decreases from a high value to a low value.
Dependencies are inferred from the claim text.