Medical ultrasonic diagnostic imaging method and apparatus
First Claim
1. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency focused at a point and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency, an improvement wherein step (a) comprises the steps of:
- (a1) applying said plurality of waveforms to a respective plurality of transducer elements, a first uni-polar waveform of said plurality of waveforms characterized by uniform amplitude and by a first value of a harmonic power ratio, waveforms transmitted from said transducer elements and corresponding to said plurality of waveforms summing as an acoustic waveform substantially at the point, said acoustic waveform characterized by a second value of said harmonic power ratio less than said first value.
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Accused Products
Abstract
An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. The transmitting step includes the step of: applying the plurality of waveforms to a respective plurality of transducer elements, a first waveform of the plurality of waveforms characterized by a first value of a harmonic power ratio, waveforms transmitted from the transducer elements and corresponding to the plurality of waveforms summing as an acoustic waveform substantially at the point, the acoustic waveform characterized by a second value of the harmonic power ratio less than the first value. The imaging method can also include a step for subdividing the transmit aperture into two or more subapertures, each subaperture having at least four adjacent transducer elements. The subapertures are phased differently with respect to one another to selectively reduce either fundamental components or harmonic components of echoes from tissue. These techniques can be used to improve contrast agent harmonic imaging as well as tissue harmonic imaging, depending upon the phase shift selected.
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Citations
73 Claims
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1. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency focused at a point and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency, an improvement wherein step (a) comprises the steps of:
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(a1) applying said plurality of waveforms to a respective plurality of transducer elements, a first uni-polar waveform of said plurality of waveforms characterized by uniform amplitude and by a first value of a harmonic power ratio, waveforms transmitted from said transducer elements and corresponding to said plurality of waveforms summing as an acoustic waveform substantially at the point, said acoustic waveform characterized by a second value of said harmonic power ratio less than said first value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
(a2) transmitting at least said first waveform, and a second and a third waveform of said plurality of waveforms from at least said first, a second and a third transducer element, respectively, said third waveform characterized by a third value of said harmonic power ratio greater than said second value and relative to at least said first and second waveforms as a function of a shape comprising a sum of said first, second and third waveforms and rising gradually to a respective maximum value and falling gradually from said respective maximum value, said acoustic waveform comprising said shape.
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19. The method of claim 1 further comprising the step of (a2) modulating a pulse width of pulses within said first waveform.
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20. The method of claim 1 further comprising the step of shaping the amplitude of said first waveform.
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21. The method of claim 1 further comprising the step or steps of any combination of two or three of steps a2 and a3:
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(a2) modulating a pulse width of at least said first waveform;
(a3) shaping the amplitude of said first waveform.
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22. The method of claim 1 wherein step (a) further comprises:
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starting transmission for at least three waveforms of the plurality of waveforms as a function of at least three different delays in addition to focusing delays; and
wherein the acoustic waveform is associated with reduced energy at the harmonic of the fundamental frequency, a characteristic of said reduction responsive to the three different delays.
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23. The method of claim 1 wherein step (a) further comprises:
transmitting from two groupings of elements the plurality of waveforms, the two groupings selected from groupings consisting of;
unequal groupings, groupings comprising at least two adjacent transducer elements and combinations thereof, the waveforms of the plurality of waveforms associated with a first one of the groupings of elements responsive to different delays than the waveforms of the plurality of waveforms associated with a second one of the groupings of elements, a characteristic of said reduction responsive to the grouping of elements.
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24. The method of claim 23 wherein step (a) further comprises:
transmitting from the first grouping with delays in addition to focusing delays and from the second grouping with focusing delays.
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25. The method of claim 24 wherein step (a) comprises:
transmitting from the first grouping, the first grouping comprising elements non-symmetrical about a center element.
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26. An apparatus for transmitting ultrasonic energy at a fundamental frequency focused substantially at a point for receipt of reflected ultrasonic energy at a harmonic of the fundamental frequency comprising:
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a transducer comprising a plurality of transducer elements;
a beamformer for applying a plurality of waveforms to said plurality of transducer elements respectively, a first uni-polar waveform of said plurality of waveforms characterized by a uniform amplitude and a first value of a harmonic power ratio, waveforms transmitted from said transducer elements and corresponding to said plurality of waveforms summing as an acoustic waveform substantially at the point, said acoustic waveform characterized by a second value of said harmonic power ratio less than said first value.
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27. A method of generating waveforms in the acoustic domain for harmonic imaging comprising the steps of:
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transmitting at a first start time at least a first waveform comprising a first number of cycles;
transmitting at a second start time at least a second waveform comprising said first number of cycles, wherein said second start time corresponds to at least a one cycle delay in addition to a focusing delay from said first start time;
said first and second waveforms acoustically summing to contribute to a third waveform at a point, said third waveform comprising a shape rising gradually to a respective value and falling gradually from said respective value.
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28. A method of generating waveforms in the acoustic domain for harmonic imaging comprising the steps of:
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transmitting at a first start time at least a first waveform comprising a first number of cycles;
transmitting at a second start time at least a second waveform comprising a second number of cycles, wherein said second number of cycles comprises at least two cycles less than said first number and said second start time corresponds to at least a one cycle delay in addition to a focusing delay from said first start time;
said first and second waveforms acoustically summing to contribute to a third waveform at a point, said third waveform comprising a shape rising gradually to a respective value and falling gradually from said respective value.
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29. A method of generating waveforms in the acoustic domain for harmonic imaging comprising the steps of:
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transmitting at least a first waveform comprising a first amplitude;
transmitting at least a second waveform comprising a second amplitude selected relative to the first amplitude in addition to an apodization amplitude;
said first and second waveforms acoustically summing to contribute to a third waveform at a point, said third waveform comprising a shape rising gradually to a respective value and falling gradually from said respective value and characterized by a number of amplitude levels greater than a number of amplitude levels associated with the first and second waveforms.
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30. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency focused at a point and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency, an improvement wherein step (a) comprises the steps of:
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(a1) starting transmission for at least three waveforms of the plurality of waveforms as a function of at least three different delays in addition to focusing delays;
said at least three waveforms acoustically summing as an acoustic waveform, the acoustic waveform associated with reduced energy at the harmonic of the fundamental frequency, the position of the reduction responsive to the three different delays. - View Dependent Claims (31, 32)
transmitting the waveforms associated with the three different delays from a first portion of an active aperture and transmitting waveforms associated with focusing delays from a second portion of the active aperture.
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33. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency focused at a point and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency, an improvement wherein step (a) comprises the steps of:
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(a1) transmitting from two groupings of elements waveforms associated with respective ones of at least two different delays, the two groupings selected from groupings consisting of;
unequal groupings, grouping comprising at least two adjacent transducer elements and combinations thereof;
said waveforms acoustically summing as an acoustic waveform, the acoustic waveform associated with reduced energy at the harmonic of the fundamental frequency, a characteristic of said reduction responsive to the grouping of elements. - View Dependent Claims (34, 35, 36)
starting transmission for at least three waveforms of the plurality of waveforms as a function of at least three different delays in addition to focusing delays;
said at least three waveforms acoustically summing as the acoustic waveform, the position of the reduction responsive to the three different delays.
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35. The method of claim 33 wherein step (a) comprises:
transmitting from unequal groupings.
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36. The method of claim 33 wherein step (a) comprises:
transmitting from groupings each comprising at least two adjacent transducer elements.
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37. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency focused at a point in a target and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency during an imaging session, the target being free of contrast agent during the entire imaging session, an improvement wherein step (a) comprises the steps of:
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(a1) applying said plurality of waveforms to a respective plurality of transducer elements during the imaging session, a first waveform of said plurality of waveforms characterized by a first value of a harmonic power ratio, waveforms transmitted from said transducer elements and corresponding to said plurality of waveforms summing as an acoustic waveform substantially at the point, said acoustic waveform characterized by a second value of said harmonic power ratio less than said first value. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63)
(a2) transmitting at least said first waveform, and a second and a third waveform of said plurality of waveforms from at least said first, a second and a third transducer element, respectively, said third waveform characterized by a third value of said harmonic power ratio greater than said second value and relative to at least said first and second waveforms as a function of a shape comprising a sum of said first, second and third waveforms and rising gradually to a respective maximum value and falling gradually from said respective maximum value, said acoustic waveform comprising said shape.
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57. The method of claim 37 further comprising the step of (a1) modulating a pulse width of pulses within said first waveform.
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58. The method of claim 37 further comprising the step of shaping the amplitude of said first waveform.
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59. The method of claim 37 further comprising the step or steps of any combination of two or three of steps a2 and a3:
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(a2) modulating a pulse width of at least said first waveform;
(a3) shaping the amplitude of said first waveform.
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60. The method of claim 37 wherein step (a) further comprises:
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starting transmission for at least three waveforms of the plurality of waveforms as a function of at least three different delays in addition to focusing delays;
the acoustic waveform associated with reduced energy at the harmonic of the fundamental frequency, a characteristic of said reduction responsive the three different delays.
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61. The method of claim 37 wherein step (a) further comprises:
transmitting from two groupings of elements the plurality of waveforms, the two groupings selected from groupings consisting of;
unequal groupings, groupings comprising at least two adjacent transducer elements and combinations thereof, the waveforms of the plurality of waveforms associated with one of the groupings of elements responsive to different delays than the waveforms of the plurality of waveforms associated with a second one of the groupings of elements, a characteristic of said reduction responsive to the grouping of elements.
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62. The method of claim 61 wherein step (a) further comprises:
transmitting from the first grouping with delays in addition to focusing delays and from the second grouping with focusing delays.
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63. The method of claim 62 wherein step (a) comprises:
transmitting from the first grouping, the first grouping comprising elements non-symmetrical about a center element.
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64. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency into a target for each of a plurality of scan lines and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency response to step (a), an improvement wherein step (a) comprises the steps of:
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(a1) changing an aperture for transmitting waveforms with different delays in addition to focusing delays as a function of an angle of one of said plurality of scan lines. - View Dependent Claims (65, 66, 67, 68, 69)
(a2) changing another aperture for transmitting waveforms with focusing delays as a function of the aperture of step (a1).
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69. The method of claim 68 wherein step (a) comprises:
placing the aperture of step (a1) off-set from a center of an active aperture.
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70. In a method comprising the steps of (a) transmitting a plurality of waveforms from a transducer at a fundamental frequency into a target for each of a plurality of scan lines and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency response to step (a), an improvement wherein step (a) comprises the steps of:
(a1) changing an aperture for transmitting waveforms with different phases in addition to focusing delays as a function of an angle of one of said plurality of scan lines. - View Dependent Claims (71, 72, 73)
Specification