Patent US5188112A successfully refreshed from Google Patents.
US5188112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic Doppler imaging systems with improved flow sensitivity
Assignee: U Systems Inc
•
Filing: 1990-11-16
•
Granted: 1993-02-23
•
Expires: 2010-11-16
Abstract
Abstract An ultrasonic blood flow measuring and imaging system comprises a transmit-receive transducer for transmitting ultrasonic waves toward and into the human body and for receiving reflected echo signals which are then processed for use in a Doppler blood flow imaging and display system. Multiple ultrasonic pulse beams are transmitted into the body at each of a number of angles in an area under diagnosis. For each angle, a plurality of reflected echo signals are received during successive predetermined time intervals. Each received echo signal has a stationary component reflected from essentially stationary tissue and a Doppler component reflected from areas where movement is sensed, such as blood flow. The reflected echo signals are processed in an MTI filter subtracting a stationary component from the received echo signals to thereby extract a Doppler signal representative of a Doppler component of the received echo signals. The Doppler component is then processed in an MTI filter equalizer having a frequency response which is the inverse of the MTI filter, for producing an output having an essentially flat frequency response over the range of frequencies being measured. The output is used to produce color flow imaging of the blood flow in the area under diagnosis.
Inventors
- 👤 Michael R. Sturgill
- 👤 Bradley K. Herres, deceased
- 👤 Paul M. Jaeger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:08
CPC Classifications
G; G01; G01S; G01S15/00; G01S15/88; G01S15/89; G01S15/8906; G01S15/8979; G01S15/8981; A; A61; A61B; A61B8/00; A61B8/48; A61B8/488
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
193 words
An ultrasonic Doppler flow measuring and imaging system comprising: (a) ultrasonic wave transmitting and receiving means for sequentially transmitting a series of at least three ultrasonic waves toward and into a living body at a selected angle over a predetermined time interval and for receiving a corresponding series of reflected echo signals, wherein each reflected echo signal in the series has a stationary component representative of reflection from essentially stationary tissue and a Doppler component representative of reflection from a moving part of the body; (b) means for processing the series of reflected echo signals, the signal processing means including (i) means for subtracting one of the reflected echo signals from each of the other reflected echo signals to cancel the stationary component from the reflected echo signals, leaving Doppler signals representative of the Doppler component of the reflected echo signals, and (ii) means for thereafter amplifying the Doppler signals to produce a succession of output signals representative of the Doppler components of the reflected echo signals; and (c) means for processing the output signals to generate therefrom Doppler flow image data signals for use in imaging the moving part of the body.
Claim 2
Dependent Claim
193 words
An ultrasonic Doppler flow measuring and imaging system comprising: (a) ultrasonic wave transmitting and receiving means for sequentially transmitting a series of at least three ultrasonic waves toward and into a living body at a selected angle over a predetermined time interval and for receiving a corresponding series of reflected echo signals, wherein each reflected echo signal in the series has a stationary component representative of reflection from essentially stationary tissue and a Doppler component representative of reflection from a moving part of the body; (b) means for processing the series of reflected echo signals, the signal processing means including (i) means for subtracting one of the reflected echo signals from each of the other reflected echo signals to cancel the stationary component from the reflected echo signals, leaving Doppler signals representative of the Doppler component of the reflected echo signals, and (ii) means for thereafter amplifying the Doppler signals to produce a succession of output signals representative of the Doppler components of the reflected echo signals; and (c) means for processing the output signals to generate therefrom Doppler flow image data signals for use in imaging the moving part of the body.
Claim 3
Dependent Claim
20 words
Apparatus according to claim 1 in which the measuring and imaging system comprises an ultrasonic Doppler blood flow measuring system.
Claim 4
Dependent Claim
65 words
Apparatus according to claim 1 in which the echo signal processing means includes means for sampling the one reflected echo signal and the other reflected echo signals a plurality of times during the time, and the subtracting means comprises means for storing the samples of the one signal and subtracting the stored samples from the samples of the other signals as the latter are returned.
Claim 5
Dependent Claim
23 words
Apparatus according to claim 1 in which the echo signal processing means produces one fewer output signal than the series of ultrasonic pulses.
Claim 6
Dependent Claim
86 words
Apparatus according to claim 4 in which the echo signal processing means includes an analog-to-digital converter (ADC) to which the reflected echo signals are applied such that the ADC samples both the one signal and the other signal, an MTI filter connected to the ADC to filter the other signals, a digital register connected to the ADC to store the one signal, and a digital-to-analog converter (DAC) connected to the register to convert the stored one signal to analog form for subtraction from the other signals.
Claim 7
Dependent Claim
24 words
Apparatus according to claim 5 in which the output signal processing means includes a velocity estimator and display system connected to the MTI filter.
Claim 8
Dependent Claim
207 words
An ultrasonic Doppler flow measuring and imaging system comprising: (a) ultrasonic wave transmitting and receiving means for sequentially transmitting a series of ultrasonic pulses toward and into a living body at a selected angle over a predetermined time interval and for receiving a corresponding series of reflected echo signals, wherein each received echo signal has a stationary component representative of reflection from essentially stationary tissue and a Doppler component representative of reflection from a moving part of the body; (b) means for processing the echo signals received during successive predetermined time intervals, the signal processing means including (i) an MTI filter for subtracting a stationary component from the received echo signals to thereby extract from the echo signals a Doppler signal representative of a Doppler component of the received echo signals, and (ii) equalization means having a frequency response which is substantially the inverse of the MTI filter and which is responsive to the output of the MTI filter for processing said output to produce an essentially flat frequency response over the range of frequencies being measured; and (c) means for processing the output signals from the equalizer means to generate therefrom Doppler flow image data signals for use in imaging the moving part of the body.
Claim 9
Dependent Claim
207 words
An ultrasonic Doppler flow measuring and imaging system comprising: (a) ultrasonic wave transmitting and receiving means for sequentially transmitting a series of ultrasonic pulses toward and into a living body at a selected angle over a predetermined time interval and for receiving a corresponding series of reflected echo signals, wherein each received echo signal has a stationary component representative of reflection from essentially stationary tissue and a Doppler component representative of reflection from a moving part of the body; (b) means for processing the echo signals received during successive predetermined time intervals, the signal processing means including (i) an MTI filter for subtracting a stationary component from the received echo signals to thereby extract from the echo signals a Doppler signal representative of a Doppler component of the received echo signals, and (ii) equalization means having a frequency response which is substantially the inverse of the MTI filter and which is responsive to the output of the MTI filter for processing said output to produce an essentially flat frequency response over the range of frequencies being measured; and (c) means for processing the output signals from the equalizer means to generate therefrom Doppler flow image data signals for use in imaging the moving part of the body.
Claim 10
Dependent Claim
20 words
Apparatus according to claim 7 in which the measuring and imaging system comprises an ultrasonic Doppler blood flow measuring system.
Claim 11
Dependent Claim
49 words
Apparatus according to claim 7 in which the echo signal processing means includes means for sampling multiple reflected echo signals during each time interval and means for subtracting therefrom a stationary bias signal component based on fewer sampled echo signals than are present in the series of echo signals.
Claim 12
Dependent Claim
47 words
Apparatus according to claim 9 including, for each time interval, means for storing a reflected echo signal, means for sampling a plurality of other reflected echo signals, and means for subtracting the stored reflected echo signal from the sampled other echo signals to extract said Doppler signal.
Claim 13
Dependent Claim
35 words
Apparatus according to claim 10 in which the echo signal processing means includes means for passing the amplified Doppler signals through an analog-to-digital converter and means for filtering the digital output in an MTI filter.
Claim 14
Dependent Claim
19 words
Apparatus according to claim 11 in which the filter output is received by a velocity estimator and display system.
Claim 15
Dependent Claim
19 words
Apparatus according to claim 12 in which the system comprises an ultrasonic Doppler blood flow measuring system and display.
Claim 16
Dependent Claim
13 words
Apparatus according to claim 13 in which the imaging system includes color imaging.
Claim 17
Dependent Claim
43 words
Apparatus according to claim 7 in which the MTI filter has a transfer function which is y(n)=x(n)-x(n-τ) and the equalization means has a transfer function which is y(n)=x(n)+by(n-τ) where b is a variable having a value greater than zero and less than 1.
Claim 18
Dependent Claim
38 words
Apparatus according to claim 7 in which the MTI filter in combination with the equalization means has a transfer function which is y(n)=x(n)-x(n-τ)+by(n-τ) where b is a variable having a value greater than zero and less than one.
Claim 19
Dependent Claim
111 words
Doppler ultrasound apparatus comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses into a target along the same line; means for receiving and down converting the frequency of the echoes from the pulses to form echo signals; means for storing the echo signal from one of the pulses; means for subtracting the echo signals from each of the other pulses from the stored echo signal to form level corrected signals; an analog to digital converter (ADC) to which the level corrected signals are applied; and means for digitally processing the level corrected signals from the ADC to form signals representative of the velocity along the line.
Claim 20
Dependent Claim
111 words
Doppler ultrasound apparatus comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses into a target along the same line; means for receiving and down converting the frequency of the echoes from the pulses to form echo signals; means for storing the echo signal from one of the pulses; means for subtracting the echo signals from each of the other pulses from the stored echo signal to form level corrected signals; an analog to digital converter (ADC) to which the level corrected signals are applied; and means for digitally processing the level corrected signals from the ADC to form signals representative of the velocity along the line.
Claim 21
Dependent Claim
18 words
The apparatus of claim 17, additionally comprising means for amplifying the level corrected signals applied to the ADC.
Claim 22
Dependent Claim
83 words
The apparatus of claim 18, in which the storing means comprises: means for applying the echo signal from the one pulse to the ADV to form a digital level correcting signal; means for storing the level correcting signal in a buffer; a digital to analog converter (DAC) to which the buffer is connected; and means for controlling the buffer and the DAC to reproduce the echo signal from the one pulse in synchronism with the echo signals from each of the other pulses.
Claim 23
Dependent Claim
27 words
The apparatus of claim 19, in which the subtracting means comprises a summing junction to which the DAC and the receiving and down converting means are connected.
Claim 24
Dependent Claim
19 words
The apparatus of claim 20, in which the amplifying means comprises an amplifier between the summing junction and ADC.
Claim 25
Dependent Claim
118 words
The apparatus of claim 21, in which the storing means additionally comprises: a first switch for alternately connecting the summing junction and the amplifier to the ADC in first and second states, respectively; a second switch for alternately connecting the ADC to the buffer and the processing means in first and second states, respectively; a third switch for disconnecting and connecting the DAC to the summing junction in first and second states, respectively; means for placing the first, second, and third switches in the first state during reception of the echoes from the one pulse; and means for placing the first, second, and third switches in the second state during reception of the echoes from the other pulses.
Claim 26
Dependent Claim
73 words
The apparatus of claim 22, additionally comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses along each of a plurality of different lines to insonify a cross sectional area of the target; means for forming a velocity representative signals for each of the different lines in the manner set forth for the first named line; and means for forming a color flow image from the velocity representative signals.
Claim 27
Dependent Claim
102 words
The apparatus of claim 17, in which the receiving and converting means also forms quadrature echo signals, the apparatus additionally comprising: means for storing the quadrature echo signal from the one pulse; means for subtracting the quadrature echo signals from each of the other pulses from the stored quadrature echo signal to form quadrature level corrected signals; an analog to digital converter (ADC) to which the level corrected signals are applied; and means for digitally processing the quadrature level corrected signals from the ADC with the first named level corrected signals to form the signals representative of the velocity along the line.
Claim 28
Dependent Claim
83 words
The apparatus of claim 17, in which the storing means comprises: means for applying the echo signal from the one pulse to the ADC to form a digital level correcting signal; means for storing the level correcting signal in a buffer; a digital to analog converter (DAC) to which the buffer is connected; and means for controlling the buffer and the DAC to reproduce the echo signal from the first pulse in synchronism with the echo signals from each of the other pulses.
Claim 29
Dependent Claim
106 words
The apparatus of claim 17, in which the processing means comprises; an MTI filter having a given frequency response for processing the level corrected echo signals from the ADC; an equalizer having a frequency response that is substantially the inverse of that of the MTI filter for processing the MTI filtered echo signals to form equalized echo signals, the MTI filter and the equalizer together having a substantially flat frequency response over the frequency range of the Doppler signal except for a notch at zero frequency; and means for processing the equalized signals from the ADC to form signals representative of the velocity along the line.
Claim 30
Dependent Claim
35 words
The apparatus of claim 26, additionally comprising an analog to digital converter (ADC) to which the echo signals are applied so that the MTI filter, the equalizer, and the processing means operate upon digital signals.
Claim 31
Dependent Claim
58 words
The apparatus of claim 27, in which the plurality of ultrasonic pulses comprises at least four pulses and the MTI filter comprises means for delaying the respective echo signals by a time interval equal to the interval between the ultrasonic pulses and subtracting the delayed echo signals from the respective echo signals to form MTI filtered echo signals.
Claim 32
Dependent Claim
49 words
The apparatus of claim 28, in which the equalizer comprises means for delaying the respective equalized echo signals by a time interval equal to the interval between the ultrasonic pulses and subtracting the delayed echo signals from the respective MTI filtered echo signals to form the equalized echo signals.
Claim 33
Dependent Claim
27 words
The apparatus of claim 29, in which the equalizer additionally comprises means for multiplying the delayed echo signals by an adjustable factor that is less than one.
Claim 34
Dependent Claim
72 words
The apparatus of claim 30, additionally comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses along each of a plurality of different lines to insonify a cross sectional area of the target; means for forming velocity representative signals for each of the different lines in the manner set forth for the first named line; and means for forming a color flow image from the velocity representative signals.
Claim 35
Dependent Claim
127 words
The apparatus of claim 26, in which the receiving and converting means also forms quadrature echo signals, the apparatus additionally comprising: an analog to digital converter (ADC) to which the quadrature echo signals are applied; an MTI filter having a given frequency response for processing the quadrature echo signals; an equalizer having a frequency response that is substantially the inverse of that of the MTI filter for processing the MTI filtered quadrature echo signals to form equalized quadrature echo signals, the MTI filter and the equalizer together having a substantially flat frequency response over the frequency range of the Doppler signal except for a notch at zero frequency; and means for processing the equalized quadrature echo signals to form signals representative of the velocity along the line.
Claim 36
Dependent Claim
22 words
The apparatus of claim 17, in which the storing means stores the echo signal from the first occurring pulse of the plurality.
Claim 37
Dependent Claim
50 words
The apparatus of claim 17, in which the transmitting means comprises an array of ultrasonic transducers and the receiving means comprises a beamformer, means for applying the echoes received by the array to the beamformer, and means for down converting the output from the beamformer to form the echo signals.
Claim 38
Dependent Claim
136 words
Doppler ultrasound apparatus comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses into a target along the same line at a pulse repetition frequency (PRF); means for receiving and down converting the frequency of the echoes from the pulses to form echo signals; an MTI filter having a given frequency response for processing the echo signals; an equalizer having a frequency response that is substantially the inverse of that of the MTI filter for processing the MTI filtered echo signals to form equalized echo signals, the MTI filter and the equalizer together having a substantially flat frequency response over the frequency range of the Doppler signal except for a notch at zero frequency; and means for processing the equalized echo signals to form signals representative of the velocity along the line.
Claim 39
Dependent Claim
136 words
Doppler ultrasound apparatus comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses into a target along the same line at a pulse repetition frequency (PRF); means for receiving and down converting the frequency of the echoes from the pulses to form echo signals; an MTI filter having a given frequency response for processing the echo signals; an equalizer having a frequency response that is substantially the inverse of that of the MTI filter for processing the MTI filtered echo signals to form equalized echo signals, the MTI filter and the equalizer together having a substantially flat frequency response over the frequency range of the Doppler signal except for a notch at zero frequency; and means for processing the equalized echo signals to form signals representative of the velocity along the line.
Claim 40
Dependent Claim
35 words
The apparatus of claim 35, additionally comprising an analog to digital converter (ADC) to which the echo signals are applied so that the MTI filter, the equalizer, and the processing means operate upon digital signals.
Claim 41
Dependent Claim
45 words
The apparatus of claim 36, in which the MTI filter comprises means for delaying the echo signals by a time interval equal to the reciprocal of the PRF and subtracting the delayed echo signals from the respective echo signals to form MTI filtered echo signals.
Claim 42
Dependent Claim
47 words
The apparatus of claim 37, in which the equalizer comprises means for delaying the equalized echo signals by a time interval equal to the reciprocal of the PRF and subtracting the delayed echo signals from the respective MTI filtered echo signals to form the equalized echo signals.
Claim 43
Dependent Claim
27 words
The apparatus of claim 38, in which the equalizer additionally comprises means for multiplying the delayed echo signals by an adjustable factor that is less than one.
Claim 44
Dependent Claim
72 words
The apparatus of claim 39, additionally comprising: means for transmitting a plurality of at least three high frequency ultrasonic pulses along each of a plurality of different lines to insonify a cross sectional area of the target; means for forming velocity representative signals for each of the different lines in the manner set forth for the first named line; and means for forming a color flow image from the velocity representative signals.
References Cited (Backward Citations)
USRE32323E
Cited
US4324258A
Cited
US4409982A
Cited
US4509525A
Cited
US4641668A
Cited
US4641668B1
Cited
US4583552A
Cited
US4622977A
Cited
US4622977B1
Cited
US4830016A
Cited
EP0197854A1
Cited
US4848355A
Cited
US4817619A
Cited
US4803990A
Cited
US4809703A
Cited
US4790323A
Cited
US4883060A
Cited
US4888694A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-02-23 | 1996-08-24 | 1997-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-23 | 2000-08-24 | 2001-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-23 | 2004-08-24 | 2005-02-23 | $7700.00 | Window Closed / Lapsed |