U.S. patent application number 11/169357 was filed with the patent office on 2007-01-18 for scalable ultrasound system and methods.
This patent application is currently assigned to Siemens Medical Solutions USA, Inc.. Invention is credited to John C. Lazenby, David A. Petersen, Robert N. Phelps.
Application Number | 20070016023 11/169357 |
Document ID | / |
Family ID | 37662508 |
Filed Date | 2007-01-18 |
United States Patent
Application |
20070016023 |
Kind Code |
A1 |
Phelps; Robert N. ; et
al. |
January 18, 2007 |
Scalable ultrasound system and methods
Abstract
A plurality of application specific integrated circuit (ASIC)
chips with different functions is provided. Each of the ASICs
performs one or more functions along an ultrasound data path. The
chips include communications protocols or processes for allowing
scaling. For example, ASICs for backend processing include data
exchange ports for communicating between other ASICs of the same
type. As another example, receive beamformer ASICs cascade for
beamformation. By providing ASICs implementing many or most of the
ultrasound data path functions, with scalability, the same ASICs
may be used for different system designs. A family of systems from
high end to low-end using the same types of ASICs, but in different
configurations, is provided.
Inventors: |
Phelps; Robert N.; (Fall
City, WA) ; Petersen; David A.; (Fall City, WA)
; Lazenby; John C.; (Fall City, WA) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Assignee: |
Siemens Medical Solutions USA,
Inc.
|
Family ID: |
37662508 |
Appl. No.: |
11/169357 |
Filed: |
June 28, 2005 |
Current U.S.
Class: |
600/437 |
Current CPC
Class: |
A61B 8/4427 20130101;
G01S 7/52046 20130101; G01S 7/52023 20130101; Y10T 29/49005
20150115; Y10T 29/4908 20150115; Y10T 29/49172 20150115; Y10T
29/4902 20150115; G01S 7/5208 20130101; G01S 7/52096 20130101; Y10T
29/49194 20150115; G10K 11/341 20130101 |
Class at
Publication: |
600/437 |
International
Class: |
A61B 8/00 20060101
A61B008/00 |
Claims
1. A scalable system for receive beamforming with ultrasound, the
system comprising: a real-time time of flight calculator operable
to determine distances to acoustic sample coordinates; a wavefront
calculator operable to change the acoustic sample coordinates to
positions along a non-straight line; and a receive beamformer
operable to form acoustic samples as a function of the
distances.
2. The system of claim 1 wherein the real-time time of flight
calculator and receive beamformer are operable without the
wavefront calculator.
3. The system of claim 2 wherein a higher cost system includes the
wavefront calculator and wherein a lower cost system is without the
wavefront calculator.
4. The system of claim 1 wherein the real-time time of flight
calculator is operable to determine distances as a cosine, sine or
cosine and sine function of element coordinates to the acoustic
sample coordinates.
5. The system of claim 1 wherein the wavefront calculator is
operable to override the acoustic sample coordinates as a function
of multiple simultaneous receive beams.
6. The system of claim 1 wherein the wavefront calculator is
operable to override the acoustic sample coordinates as a function
of aberrations.
7. The system of claim 1 wherein the wavefront calculator is
operable to override the acoustic sample coordinates as a function
of a Gaussian beam wavefront.
8. The system of claim 1 wherein the receive beamformer and
real-time time of flight calculator are operable to output the
acoustic samples and wherein the wavefront calculator is operable
to provide reconstruction coefficients for converting the acoustic
sample coordinates to a linear space.
9. The system of claim 1 wherein the wavefront calculator is
operable to change the acoustic sample coordinates as a function of
a location as a function of time, a lateral density of samples and
a lateral extent.
10. A scalable system for medical diagnostic ultrasound imaging,
the system comprising: a first type of integrated circuit operable
to perform a first function along an ultrasound data path, the
first type of integrated circuit operable with one or more of the
first type of integrated circuits substantially in parallel
relative to the ultrasound data path; and a second type of
integrated circuit operable to perform a second function along the
ultrasound data path, the second function responsive to data output
by the first type of integrated circuit; wherein the ultrasound
data path has at least first and second complexity levels, the
first complexity level associated with a lower cost medical
diagnostic ultrasound imaging system and a fewer number of the
first type of integrated circuits and the second complexity level
associated with a higher cost medical diagnostic ultrasound imaging
system and a greater number of the first type of integrated
circuits.
11. The scalable system of claim 10 wherein the first type of
integrated circuit are operable with different powers.
12. The scalable system of claim 10 wherein the lower cost medical
diagnostic ultrasound imaging system is a portable system and the
higher cost medical diagnostic ultrasound imaging system is a cart
based system.
13. The scalable system of claim 10 wherein the lower cost medical
diagnostic ultrasound imaging system has fewer transducer connector
ports, a lesser image resolution capability and less power than the
higher cost medical diagnostic ultrasound imaging system.
14. The scalable system of claim 10 wherein the first type of
integrated circuit is operable to perform transmit beamforming,
receive beamforming, transmit and receive switching or combinations
thereof.
15. The scalable system of claim 14 wherein the first type of
integrated circuit is operable to perform receive beamforming with
a variable number of simultaneous receive beams, the lower cost
medical diagnostic ultrasound imaging system configured to operate
with a fewer number of the simultaneous receive beams than the high
cost medical diagnostic ultrasound imaging system.
16. The scalable system of claim 15 wherein the first type of
integrated circuit is operable for scaling across an array and
scaling by common connection to array elements.
17. The scalable system of claim 16 wherein the first type of
integrated circuit includes a beamsum input, a channel input, a
beamsum output and a channel output, the channel output associated
with passing the channel input without alteration and the beamsum
output summing the channel input with the beamsum input.
18. The scalable system of claim 15 wherein the high cost medical
diagnostic ultrasound imaging system includes a third type of
integrated circuit not included in the low cost medical diagnostic
ultrasound imaging system, the third type of integrated circuit
operable to change acoustic sample coordinates used by the first
type of integrated circuit to positions along a non-straight
line.
19. The scalable system of claim 10 wherein the second type of
integrated circuit is operable to perform detection, scan
conversion, image processing or combination thereof, and is
operable to exchange data for parallel processing.
20. The scalable system of claim 19 wherein the low and high cost
medical diagnostic ultrasound systems each use a single one of the
second type of integrated circuit.
21. The scalable system of claim 10 further comprising a middle
cost medical diagnostic ultrasound system for a third complexity
level of the ultrasound data path, a fewer number of the first type
of integrated circuits being in the middle cost medical diagnostic
ultrasound system than the high cost medical diagnostic and a
greater number of the first type of integrated circuits being in
the middle cost medical diagnostic ultrasound system than the low
cost medical diagnostic system.
22. A method for scalable manufacturing of medical diagnostic
ultrasound imaging systems, the method comprising: providing a
first set of application specific integrated circuit chips having
ultrasound functions; assembling a second set of the application
specific integrated circuit chips from the first set for a first
type of medical diagnostic ultrasound imaging system; and
assembling a third set of the application specific integrated
circuit chips from the first set for a second type of medical
diagnostic ultrasound imaging system, the first type of medical
diagnostic ultrasound imaging system different than the second
type; wherein the third set includes at least two types of
application specific integrated circuit chips also included in the
second set.
23. The method of claim 22 wherein at least one type of the
application specific integrated circuit chips is operable with
different powers.
24. The method of claim 22 wherein assembling the second set
comprises assembling a lower cost medical diagnostic ultrasound
imaging system, and assembling the third set comprises assembling a
higher cost medical diagnostic ultrasound imaging system.
25. The method of claim 24 wherein assembling the second set
comprises assembling with fewer of a beamforming type of
application specific integrated circuits for the lower cost medical
diagnostic ultrasound imaging system and assembling the third set
comprises assembling with more of the beamforming type of
application specific integrated circuits for the higher cost
medical diagnostic ultrasound imaging system.
26. The method of claim 25 where assembling the second and third
sets comprise setting the beamforming type of application specific
integrated circuits for a fewer number of maximum simultaneous
receive beams for the lower cost medical diagnostic ultrasound
imaging system than for the higher cost medical diagnostic
ultrasound imaging system.
27. The method of claim 22 wherein assembling the third set
comprises including at least one type of application specific
integrated circuit not in the second set.
28. The method of claim 22 wherein assembling the second and third
sets comprise assembling a plurality of receive beamforming
application specific integrated circuits and one or more detection,
scan conversion, image processing or combination thereof
application specific integrated circuits.
29. The method of claim 22 further comprising assembling a fourth
set of the application specific integrated circuit chips from the
first set for a third type of medical diagnostic ultrasound imaging
system, the third type of medical diagnostic ultrasound imaging
system different than the first and second types; wherein the
fourth set includes at least two types of application specific
integrated circuit chips also included in the second set.
30. The method of claim 22 wherein assembling the second and third
sets comprise summing a beamsum input with a channel input and
passing the channel input to a channel output without alteration.
Description
BACKGROUND
[0001] The present embodiments relate to medical diagnostic
ultrasound systems. In particular, common application specific
integrated circuits (ASICs) are provided.
[0002] Medical diagnostic ultrasound systems include ultrasound
data processing paths. Ultrasound data processing paths include
transmit beamformers, receive beamformers, detectors, scan
converters, image processors and other stages. The ultrasound data
path acquires ultrasound data and generates an image from the
ultrasound data. Typically, an ultrasound data path used for any
given type of system is independently designed. Low cost systems
have different bandwidth, power consumption, features or other
characteristics as compared to high cost systems.
[0003] Within a given system, a given ASIC may be used multiple
times. For example, a receive beamforming ASIC is designed for
operation with a limited number of channels, such as 8 or 16
channels. By providing a plurality of these ASICs in parallel, an
ultrasound imaging system with a larger number of channels is
provided. For low cost systems, the ASICs may be simple. For high
cost systems, different ASICs are used. For example, U.S. Pat. No.
5,675,554 provides ASICs capable of different bandwidths as a
number of different simultaneous beams are formed. Cascaded
summation is then provided to beamformer across the plurality of
ASICs.
[0004] A same type of ASIC may be used in different products. For
example, two different manufacturers use a same system for
different products or brand names. Since the systems are the same,
providing the same capabilities within the hardware, the same ASICs
are used. When a new system is designed, new ASICs are developed.
However, the design of new ASICs is expensive and time
consuming.
BRIEF SUMMARY
[0005] By way of introduction, the preferred embodiments described
below include methods and systems for scalable ultrasound imaging
systems. A plurality of application specific integrated circuit
chips with different functions is provided. Each of the ASICs
perform one or more functions along an ultrasound data path. The
chips include communications protocols or processes for allowing
scaling. For example, ASICs for backend processing include data
exchange ports for communicating between other ASICs of the same
type. As another example, receive beamformer ASICs cascade for
beamformation. By providing ASICs implementing many or most of the
ultrasound data path functions, with scalability, the same ASICs
may be used for different system designs. A family of systems from
high end to low-end using the same ASICs, but in different
configurations, is provided.
[0006] In one example of scalability, a receive beamformer ASIC is
operable to determine spatial coordinates associated with a given
beam along a straight line using real-time time of flight
calculations. More complex systems include more advanced coordinate
capabilities. Where multiple beams are received simultaneously, the
spatial coordinates associated with the beams may be along a
non-straight line. Similarly, Gaussian wavefronts or aberrations
may contribute to receiving along spatial coordinates along a
non-straight line. A wavefront calculator is provided in addition
to the real-time time of flight calculator to implement the
additional functionality in a high cost system. The wavefront
calculator changes the acoustic sample coordinates used by the
received beamformer. The time of flight calculator then calculates
distances to the changed acoustic sample coordinates.
[0007] In a first aspect, a scalable system is provided for receive
beamforming with ultrasound. A real-time time of flight of
calculator is operable to determine distances to acoustic sample
coordinates. A wavefront calculator is operable to change to the
acoustic sample coordinates to positions along a non-straight line.
A receive beamformer is operable to form acoustic samples as a
function of the distances.
[0008] In a second aspect, a scalable system is provided for
medical diagnostic ultrasound imaging. A first type of integrated
circuit is operable to perform a first function along an ultrasound
data path. The first type of integrated circuit is operable with
one or more of the first type of integrated circuits substantially
in parallel relative to the ultrasound data path. A second type of
integrated circuit is operable to perform a second function along
the ultrasound data path. The second function is responsive to data
output by the first type of integrated circuit. The ultrasound data
path has at least two different levels of complexity. A first level
is associated with a lower cost medical diagnostic ultrasound
system and a fewer number of the first type of integrated circuits.
A second complexity level is associated with a higher cost medical
diagnostic ultrasound system and a greater number of the type of
integrated circuits.
[0009] In a third aspect, a method is provided for scalable
manufacturing of medical diagnostic ultrasound imaging systems. A
first set of application-specific integrated circuit chips having
ultrasound functions is provided. A second set of
application-specific integrated circuit chips is assembled from the
first set for a first type of medical diagnostic ultrasound imaging
system. A third set of the application-specific integrated circuit
chips from the first set is assembled for a second type of medical
diagnostic ultrasound imaging system. The first type of medical
ultrasound system is different than the second type, such as by
having different hardware-based functionality. The third set
includes at least two types of application-specific integrated
circuits also included in the second set.
[0010] The present invention is defined by the following claims,
and nothing in this section should be taken as a limitation on
those claims. Further aspects and advantages of the invention are
discussed below in conjunction with the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The components and the figures are not necessarily to scale,
emphasis instead being placed upon illustrating the principles of
the invention. Moreover, in the figures, like reference numerals
designate corresponding parts throughout the different views.
[0012] FIG. 1 is a block diagram of one embodiment of a scalable
medical diagnostic ultrasound imaging system;
[0013] FIG. 2 is a block diagram of one embodiment of an
arrangement of application-specific integrated circuits for a
low-end ultrasound system;
[0014] FIG. 3 is a block diagram of one embodiment of an
arrangement of application-specific integrated circuits for a
higher end ultrasound system;
[0015] FIG. 4 is a block diagram of a receive beamformer operating
with two different spatial coordinate calculators in one
embodiment;
[0016] FIG. 5 is a flowchart diagram of one embodiment of a method
for scaling an ultrasound system; and
[0017] FIG. 6 is a block diagram an ASIC with scalable beam-channel
product.
DETAILED DESCRIPTION OF THE DRAWINGS AND PRESENTLY PREFERRED
EMBODIMENTS
[0018] A mix and match chip set is provided for building different
medical diagnostic ultrasound systems. Chips for performing
different functions are used in portable as well as higher-end
systems. A given application-specific integrated circuit may not
span an entire range of possible systems, but may be used in two or
more different systems. By providing application-specific
integrated circuits (ASICs) scaled for size, power and/or
performance, the same circuits may be used for multiple ranges or
types of systems. For example, one standardized integrated circuit
includes transmit waveform generators, transmit drivers, transmit
receive switches, pre-amplification, time gain control and any
sub-array or time multiplex devices. An additional integrated
circuit is a receive beamformer designed to scale the number of
channels and/or beams. For multiple simultaneous receive beams, an
integrated circuit is provided for tracking wavefronts to better
steer the receive beamformer. Accordingly, the receive beamformer
ASICs may be simplified for use with lower end systems. One or more
backend ASICs provide for processing from radio frequency to
audio/video conversion, such as providing for detection,
pre-detection processes, post-detection processes, scan conversion
or other functions.
[0019] FIG. 1 shows one embodiment of a scalable system 10 for
medical diagnostic ultrasound imaging. The system 10 includes a
transducer 12, a analog frontend ASIC 14, a digital frontend ASIC
16, a backend ASIC 18, a cable 20 between the digital frontend and
the backend ASICs 16, 18 or elsewhere (e.g. between the transducer
12 and the analog frontend ASICs 14), and other external devices,
such as a memory 22, an audio device 24, a display device 26, a
general control processor 28, and/or a memory 30 for the control
processor 28. Additional, different or fewer components may be
provided. For example, the digital frontend ASIC 16 is divided into
two separate ASICs, one associated with transmit and the other
associated with receive. As another example, the backend ASIC 18 is
divided into a plurality of different ASICs, such as a prior to
detection ASIC, a detection ASIC, and a post-detection ASIC.
[0020] The system 10 is a medical diagnostic ultrasound system. In
one embodiment, the system 10 is a portable, such as a handheld,
medical diagnostic ultrasound system with analog and digital
frontend ASICs 14, 16 within a transducer head or probe. In
alternative embodiments, the system 10 is a cart-based or other
more complex medical diagnostic ultrasound system.
[0021] The medical diagnostic ultrasound system 10 includes an
ultrasound data path between the transducer 12 and the display 26.
The ultrasound data path is responsible for acquiring ultrasound
data. For example, the digital frontend ASIC 16 generates transmit
waveform control signals for operating a transmit pulser connected
with the transducer 12. In response to echoes, a receive beamformer
generates samples for detection, scan conversion or other processes
to generate ultrasound data representing a scanned region. Any now
known or later developed function for providing an ultrasound image
performed by medical diagnostic ultrasound system may be provided
along the ultrasound data path.
[0022] In the example of FIG. 1, three different
application-specific integrated circuits 14, 16, 18 are provided.
The analog frontend ASIC 14 includes an integrated transmit pulser
32, such as for operation from 60 to 100 volts peak. Other peak
voltage may be provided, such as greater or lesser voltages.
Unipolar, bipolar or other transmit pulsers may be implemented. An
integrated transmit and receive switch 34 switches operation of the
transducer 12 between the transmit pulser 32 and a receive path
with the preamplifier 36. The preamplifier 36 along with a time or
depth gain control amplifier 38 are operable with a variable bias
and power supply, such as providing for reduced voltages on the
amplifier power rails or a programmable amplifier bias. For
operation in low-end systems, reduced voltage and amplifier bias
may be used to conserve power, such as for handheld battery
operation. For high end systems, an increased voltage and amplifier
bias may allow for better dynamic range and linearity while using
the same component. Bias variation can be used to trade off dynamic
range, sensitivity, frequency response and/or power dissipation to
provide receive solutions over a wide range of products.
[0023] In one embodiment, a mixer and multiplexer 40 is provided
for sub-array mixing, time division multiplexing, partial
beamforming or other aperture reduction technique, such as
disclosed in U.S. Patent Nos. 5,573,001, ______, ______
(application Ser. Nos. 10/788,021; 10/741,827; 10/741,438; and
10/834,779), the disclosures of which are incorporated herein by
reference. For spectral Doppler or high frequency transducer
operation, a bypass may be provided to support high bandwidth
operation. The bypass bypasses the mixer multiplexer 40.
Alternatively, aperture reduction is not provided.
[0024] In one embodiment, the frontend analog ASIC 14 uses 0.13
micron mixed signal technology to achieve high circuit density.
Each frontend analog ASIC 14 provides 8, a greater or lesser number
of channels. For operation with large apertures, a plurality of
parallel analog ASICs 14 is provided. Alternatively or
additionally, one or more of the analog ASICs 14 connects with more
than 8 elements of the transducer 12 and uses the sub-array mixing
or aperture reduction provided by the mixer multiplexer 40. 50
milliwatts on transmit and 50 milliwatts on receive are provided
for lower power operation per channel or for a low channel count
system. Greater or lesser powers may be provided.
[0025] The digital frontend ASIC 16 includes a transmit beamformer
42 and transmit controller 44. The transmit beamformer 42
calculates delay and apodization profiles for one or more channels.
In response to signals from the transmit beamformer 42, the
transmit controller 44 generates driving signals for the transmit
pulser 32. Automatic tissue equalization and gain controller 46
generates control signals for time gain control and other gain
control operations. A digital-to-analog converter 48 converts the
signals to analog signals for use by the adjustable gain amplifier
38. An analog-to-digital converter 50 receives analog signals and
converts them to digital signals for receive beamformation by the
receive beamformer 52. The receive beamformer 52 generates receive
samples from a subaperture or plurality of elements using delay
profiles and apodization.
[0026] In the embodiment shown in FIG. 1, the transmit
beamformation, receive beamformation and gain control functions are
implemented in a same frontend digital ASIC 16, but may be
implemented in two or three different ASICs 16. The components of
the digital frontend ASIC 16 are operable in response to various
clock speeds for reducing power consumption depending on need.
Different components within the digital ASIC 16 may be turned off
while not in use or as a function of the type of system for which
the ASIC 16 is being used. For example, about 9 watts, but greater
or lesser wattage may be provided, are dissipated by operating all
of the components of the digital frontend ASIC 16. In one
embodiment, the digital frontend ASIC 16 is the receive beamformer
disclosed in U.S. Nos. 5,369,624; 5,388,079; and 5,544,128, the
disclosures of which are incorporated herein by reference.
[0027] Any number of channels may be implemented by a single
digital frontend ASIC 16, such as 16 channels using single beam
transmit and receive. 90 nanometer or other sized ASIC traces are
used. In one embodiment, the receive beamformer 52 is operable in 1
to 4 beam simultaneous receive beam modes. For example, separate
amplifiers, delays, phase rotators or other receive beamformer
components are provided for each channel and each possible beam. As
another example, the digital frontend ASIC 16 connects with a fewer
number of channels of the transducer 12 than are available by the
receive beamformer 52, such as half the number of channels for
implementing two substantially simultaneous receive beams. 16
channels are used to make 4 beams while connected to four elements.
By time interleaving data or aperture reduction, data from a
greater number of elements may be provided for implementing receive
beamformation by a single digital ASIC 16. For example, 16 channels
or elements are connected providing for the interleaving of four
elements on each channel. For single beam operation, 64 elements
may be connected to a single digital frontend ASIC 16. Other
numbers of total channels may be provided, such as 24. Using time
interleaving, the input rate may be different from the output rate,
such as input rate of 50 MHz and output rate of 200 MHz. Using time
interleaving, a greater number of beams may be formed given the
same inputs.
[0028] The digital frontend ASIC 16 is scalable, such as providing
for 3, 4, 6 or 12 of the same frontend ASIC 16 operating in
parallel. Greater or fewer or different numbers may be provided.
Parallel operation is provided by cascaded summation of receive
beamform signals. A final one of the digital frontend ASICs 16
performs the complete receive beamformation summation for passing
through the cable 20 or to the backend ASIC 18. In other
embodiments, two or more different ones of the digital frontend
ASICs 16 connect to the same channels or overlapping channel
apertures of the transducer 12 for implementing multiple
substantially simultaneous receive beams.
[0029] The analog frontend ASIC 14 and the digital frontend ASIC 16
include configurable power dissipation. Dynamic range is sacrificed
for lesser power. Power rails may vary, such as providing more than
one rail to connect with external power sources. Bias current on
amplifiers may be lowered, reducing linearity and power
consumption. In a bypass mode, one of the mixers within the mixer
multiplex 40 is used for low-cost continuous wave
implementation.
[0030] The backend ASIC 18 is a digital ASIC with an adjustable
clock rate. The plurality of signal ports 60 connect with other
components, such as a USB, radio frequency, PCI, DVI and/or other
inputs. Fewer or different inputs than shown may be provided. By
providing different signal ports, different levels of integration
are provided. The PCI interface allows for high end or higher
bandwidth processing connection with the processor controller 28.
USB allows for lower end or lower bandwidth control. In the
embodiment shown in FIG. 1, a single backend ASIC 18 is provided
for simple or low-end system 10. Two or more ASICs 18 may be
provided in parallel for higher end operation.
[0031] The digital receiver 62 is operable to receive up to 80 mega
samples per second, but greater or lesser rates may be provided.
The digital receiver 62 implements base band filtering or
processing. The memory controller 61 operates with the external
memory 22 for storing data for use within the backend ASIC 18.
Intensity, such as B-mode or M-mode echo detection is provided by
the echo detector 64. Flow detection, such as velocity, power, or
variance, is provided by the flow detector 74. Pre- and
post-detection processing may be provided. For example,
post-detection B-mode or flow processing is provided in component
68. For higher end operation, different aspects of the post- and
pre-detection components may be turned off or enabled, altering
power consumption. In-phase and quadrature information are
processed prior to detection by the complex processors 65 and 66.
The echo complex processor 65 and flow processor 66 operate for
multiple simultaneous receive beamformation. For example, different
beams are interpolated or synthesized from receive beams for
increased beam density using complex processes. Scan conversion is
provided by coordinate reformatter 70. A display processor 76, such
as a frame buffer, outputs digital video information to the display
26. Additional, different or fewer components may be provided.
[0032] For spectral and/or M-mode processing, a wall filter, gap
estimation, fast Fourier transform, audio processing and statistics
computations are provided by the spectral audio processor 72. Gap
estimation interpolates between temporal samples of spectral or
M-mode information. Any of various statistics may be provided, such
as a mean, maximum, minimum or other value. Sweeping, scrolling, or
graphical trace spectral Doppler functions are provided.
[0033] The data ports 78 share data between the backend ASICs 18
used in parallel. Data processing is divided between backend ASICs
18 as a function of time or spatial location. For example, one ASIC
is responsible for data processing associated with one portion of a
scanned region, such as every other scan line. Where data is to be
exchanged between ASICs, such as associated with filtering adjacent
spatial locations, the ports 78 provide the data. Different ASICs
18 may perform different axial functions. For lateral processing,
data is exchanged through the port 78. As another example, spectral
Doppler operations are performed using the same data sets in each
of parallel backend ASICs 18. Fourier transform processing is
performed in parallel, but optimized for outputting different
temporal samples. The wall filtering, gap estimation and fast
Fourier transform are divided over time, such as for every other
temporal sample between parallel ASICs 18. Where a given backend
ASIC 18 is optimized to receive data from only the sub-apertures,
the data is transferred through the port 78 to other backend ASICs
18 for fast Fournier transforming from a full sampling.
[0034] The display processor 76 includes a buffer for providing
low-end graphics, such as a user name or other general system
function summaries directly from the backend ASIC 18 for the
display 26. For higher end displays, graphics generated by the
controller 28 may be routed through the display processor 76 to the
display 26. Using the coordinate reformatter 70, different
resolutions may be provided for different types of data. For
example, 12 mega samples per second scan conversion is provided for
B-mode, velocity, variance or power imaging, 24 mega samples per
second are provided for sweep, scroll and vertical scaling
associated with M-mode and spectral imaging, and 80 mega samples
per second are provided for color frame interpolation to generate
color frames for temporal appeal (e.g., receiving 10 frames per
second and interpolating 60 frames per second). Other differences
in distribution of display processing with fewer or greater samples
per second may be provided. In one embodiment, post-processing
look-up tables, such as color maps for flow imaging, are integrated
as part of the backend ASIC 18. Alternatively, one or more
functions described above for the backend ASICs 18 are performed in
separate ASICs or by other devices. For example, the pre- and
post-detection processes are divided amongst two different ASICs.
Each of the ASICs may be then scaled separately. As another
example, scan conversion is provided by a different ASIC or other
display processing.
[0035] FIGS. 2 and 3 show two embodiments of a scalable system for
medical diagnostic ultrasound imaging. Each of the embodiments
includes one or more of a first type of integrated circuit 80 and
are or more at a second type of integrated circuit 82. Additional,
different or fewer components may be provided. For example, a third
type of integrated circuit common to both systems may be provided.
As another example, additional or fewer of the first or second
types of integrated circuits 80, 82 is provided. As yet another
example, one type of integrated circuit is used in one of the
systems, such as the system of FIG. 3, and not in the other system,
such as the system of FIG. 2. For simplicity, additional features
or components, such as transducers, displays, memories,
controllers, general processors, or other components along an
ultrasound data path are not shown.
[0036] The systems of FIGS. 2 and 3 use integrated circuits 80, 82
common to both systems. By using scalable integrated circuits 80,
82, different types of systems with different capabilities are
provided with mixed and matched integrated circuits 80, 82. For
example, FIG. 2 shows three beamformer type integrated circuits 80
being used with a single backend integrated circuit 82, and FIG. 3
shows six of the beamformer type integrated circuits 80 used with
two of the backend type integrated circuits 82. Providing scalable
integrated circuits 80, 82 allows for growth in the number of
channels, processing bandwidth, or addition of features.
[0037] The first type of integrated circuit 80 performs one or more
functions along an ultrasound data path. Different types of
integrated circuits are used to distinguish between integrated
circuits performing different functions. A given type of integrated
circuit performs the same function and is a same device despite
being used in different systems. Different systems provide
different circuit arrangements or platforms. Different products may
use a same system, such as a same circuit or platform provided in a
different housing, but are sold through different marketing
approaches, or programmed with different software.
[0038] The first type of integrated circuit 80 is operable with
other ones of the same type of integrated circuit 80 or alone. For
example, both FIGS. 2 and 3 show parallel operation of the same
type of integrated circuit 80. In FIG. 2, the first type of
integrated circuits 80 are provided in parallel operation across
transmit or receive apertures or channels. In FIG. 3, parallel
operation is provided across the apertures or channels as well as
across a number of beams being formed using the same channels.
Since the integrated circuits 80, 82 are provided along or form an
ultrasound data path, the operation is provided in parallel
relative to the ultrasound data path.
[0039] For scaling, the first type of integrated circuit 80
includes data connectivity between the integrated circuits 80. For
example, each of the integrated circuits 80 has an input for
receiving partially beamformed data and an output for outputting
further partially summed or completely summed beamformed data. The
input may be operable with a no connection. Cascaded receive
beamforming or summation is provided to output receive beamformed
samples from a final one of the first type of integrated circuits
80. In addition to scaling, the integrated circuits may be operable
with different power levels. For example, different power or
voltage rails are provided. As another example, different
components within the integrated circuit 80 may be selectively
disabled. As yet another example, amplifiers are provided with a
programmable bias.
[0040] Any function along an ultrasound data path may be
implemented by the first type of integrated circuit 80. In the
example shown in FIGS. 2 and 3, the first type of integrated
circuit 80 is the digital frontend ASIC 16 of FIG. 1.
Alternatively, the first type of integrated circuit 80 implements
the analog frontend ASIC 14 of FIG. 1. In yet other embodiments,
the first type of integrated circuit 80 implements other functions
or a subset of the functions, such as implementing receive
beamforming without transmit beamforming or time gain control. For
example, the first type of integrated circuit 80 implements
transmit beamforming, receive beamforming, transmit and receive
switching, a portion of any of the above-described functions or
combinations thereof.
[0041] In one embodiment, the first type of integrated circuit 80
performs receive beamforming with a variable number of simultaneous
receive beams. The same integrated circuit 80 may be connected to
different channels as shown in FIGS. 2 and 3 or scaled by common
connection to the same array elements for implementing additional
receive beamformation as shown in FIG. 3. A single one of the first
type of integrated circuits 80 may be operable with a variable
number of simultaneous receive beams. For example, time division
multiplexing is provided for connecting 16 or other number of
inputs to 64 different channels. The receive beamform sum signal
from all 64 channels is output from the single first type of
integrated circuit 80. The samples represent a single beam. For
generating two different receive beams, a multiplexer connects the
integrated circuit 80 to only 32 channels. Since the integrated
circuit 80 has capacity for 64 channels of operation, the redundant
channels are used to form a separate or different receive beam in
parallel or substantial simultaneously. Where a greater number of
receive beams or the capability for receiving a greater number of
substantially simultaneous receive beams is desired, such as
associated with higher end systems, the given one of the first type
of integrated circuits 80 is connected to a fewer number of
channels.
[0042] FIG. 4 shows one embodiment of a scalable system for receive
beamforming with ultrasound. The first type of integrated circuit
80 includes a receive beamformer 83 and a real-time time of the
flight calculator 85. The integrated circuit 80 is connectable or
connects with the transducer 12. The integrated circuit 80 is
operable without additional components for forming receive beams
associated with an aperture along the transducer 12. A wavefront
calculator 84 is connectable with the integrated circuit 80 for
more complex operation. The integrated circuit 80 is a low cost
fixed beamformer, and the wavefront calculator 84 alters operation
of the low cost fixed beamformer for more complex information
processes.
[0043] The real-time time of flight calculator 85 determines
distances to acoustic sample coordinates. The time of flight
calculator 85 includes a counter for counting clock pulses. The
outbound time for the acoustic wavefront is common to all the
elements of the array 12 and is determined with the counter. The
return echo time is determined for each element of the array 12.
For receive operation, dynamic focusing is provided by determining
a distance to a current receive focal point for each of the
elements within the aperture. Using sine, cosine or both cosine and
sine functions, distance is determined as a function of element
location and associated acoustic sample locations. For example, a
distance from a given element to a position along a straight scan
line 86 is calculated. Given the distance and the speed of sound, a
time of flight relative to different acoustic sample locations
along the scan line 86 is calculated. In one embodiment, the
real-time time of flight calculator disclosed in U.S. Pat. No.
5,501,219, the disclosure of which is incorporated herein by
reference, is used. Other time of flight calculators may be
provided.
[0044] During a scan, the position of the scan line 86 is a
function of scan line origin along the transducer 12 and/or angle
relative to the transducer 12. The real-time time of flight
calculator 85 determines the distance to each acoustic sample as
needed during operation. As each scan line 86 is repositioned for
scanning an object, the determined time of flight or distances may
be updated through interpolation. Alternatively, the time of flight
is independently calculated for each scan line. Since the beam
coordinates are typically close to each other and close to the
focus transmit beam, the echo path for all the beam coordinates or
acoustic sample coordinates along a given scan line 86 are based on
counting elapsed time and the velocity of sound.
[0045] Given a few beams and a transmit focus, the outbound
transmit path is simplified to an accounting of time from the
initiation of the transmit beam center or origin from the
transducer 12 to the range of interest. Beam coordinates are then
generated from the point of initiation along straight scan line 86
of propagation. However, if multiple receive beams are formed
substantially simultaneously in response to a single transmit beam,
each of the receive beams may be warped by the distribution of
acoustic energy in the transmit beam. Simple time of flight
calculation may not accurately model the characteristics of a
coherent acoustic wavefronts affected by wavelength and aperture.
Aberrations may also result in inaccuracies. For implementation in
simple systems, sacrifices associated with straight line assumption
for receive beamforming may be used. For more complex systems,
greater accuracy or resolution may be desired. The wavefront
calculator 84 implements more accurate receive beamforming. The
time of flight delay is partitioned into the simple scheme provided
by the time of flight calculator 85 and the more sophisticated
scheme provided by the wavefront calculator 84.
[0046] The time of flight calculator 85 includes inputs or ports
for receiving externally generated acoustic sample coordinates. The
wavefront calculator 84 is a separate component than the first type
of integrated circuit 80. If the wavefront calculator 84 is
connected with the time of flight calculator 85, the reception of
external acoustic sample coordinates is activated. Since a given
point in space has a common outbound time of flight, a single
wavefront calculator 84 may be provided for each element of the
transducer 12 or all of the first type of integrated circuits 80
implementing a receive beamforming function. The wavefront
calculator 84 operates independent of the number of channels or
beamformer devices. The wavefront calculator 84 is an integrated
circuit, ASIC, processor, controller, memory, look-up table,
digital signal processor, analog circuit, digital circuit, field
programmable gate array, combinations thereof or other now known or
later developed device for determining acoustic sample
coordinates.
[0047] Rather than a sine or cosine scaled counter, the wavefront
calculator 84 determines acoustic sample coordinates along
non-straight lines. For example, FIG. 4 shows receiving along two
curved lines 88 generally corresponding to a curved distribution of
acoustic energy associated with a transmit beam 90 along a scan
line 86. The transmit wavefront is determined as a function of
time, the density of the receive samples (e.g., the number of
simultaneous receive beams), and the extent laterally of the
acoustic energy of the transmit beam 90. By receiving multiple
simultaneous receive beams distributed laterally within the
transmit beam 90, one or more of the receive beams 88 is along a
non-straight line. Other calculations may alternatively or
additionally be performed, such as associated with determining
Gaussian beam estimations or dynamically updating wavefront
anomalies associated with tissue aberrations.
[0048] The wavefront calculator 84 outputs the acoustic sample
coordinates to the time of flight calculator 85. The output
acoustic sample coordinates changes the acoustic sample coordinates
to be used by the time of flight calculator. The change is to an
input coordinate instead of or as an alternative to using a
coordinate determined by the time of flight calculator 85. By
loading the acoustic sample coordinates determined by the wavefront
calculator 84, the time of flight calculator 85 changes the
acoustic sample coordinates, overriding the internal coordinate
determination functions. The acoustic sample coordinates are loaded
synchronously with the internal timing of the time of flight
calculator 85. The outbound time of flight remains or uses the
counter, and return echo time of flight is based on a distance to
the acoustic sample coordinates loaded from the wavefront
calculator 84.
[0049] For subsequent processing, the wavefront calculator 84
generates reconstruction coefficients for converting acoustic
sample coordinates to a linear space. The coefficients are
interpolation values, weighting, or a definition of the sample grid
used for calculating the acoustic sample coordinates. Each sample
is associated with a coefficient for reconstructing the data at a
later stage, such as prior to detection or before or after any
synthetic or complex sample processing. Outputting coefficients may
complicate later signal processing, but allows for more simplistic
implementation of the receive beamformer 83 of the first type of
integrated circuit 80. The computations for beamforming tend to be
more extensive given large channel counts than scaling or
converting acoustic samples.
[0050] The receive beamformer 83 forms the acoustic samples as a
function of distances received from the time of flight calculator
85. The acoustic samples are formed for a portion of an aperture on
the transducer 12 or for the entire aperture. The real-time time of
flight calculator 85 and receive beamformer 83 are operable without
the wavefront calculator 84. For example, a lower cost system is
implemented without the wavefront calculator 84. A higher cost
system includes the wavefront calculator 84. In response to
distances provided by the time of flight calculator 85 based on
simple straight line geometry or more complex geometry provided by
the wavefront calculator 84, the receive beamformer 83 outputs
acoustic samples with or without additional reconstruction
coefficients.
[0051] In alternative embodiments, the first type of integrated
circuit 80 operating as a receive beamformer includes the wavefront
calculation components. In yet other embodiments, a receive
beamformer with database or lookup table based delay profiles is
provided.
[0052] The second type of integrated circuit 82 shown in FIGS. 2
and 3 is the back end ASIC 18 of FIG. 1 or a different integrated
circuit. The second type of integrated circuit 82 performs an
additional function along the ultrasound data path. For example,
functions include: base band processing detection, scan conversion,
image processing, predetection synthesis, complex processing, scan
conversion, continuous wave image processing, quantification or
combinations thereof. The function performed by the second type of
integrated circuit 82 is responsive to data output by the first
type of integrated circuit 80. For example, acoustic samples are
output by the first type of integrated circuit 80. The second type
of integrated circuit 82 receives the acoustic samples and
generates image data. Alternatively, the second type of integrated
circuit 82 receives input data and outputs data subjective to
further processing but not in a format or values for display.
[0053] The second type of integrated circuit 82 is scalable. For
example, FIG. 2 shows one of the second type of integrated circuits
82, and FIG. 3 shows two of the second type of integrated circuits
82 in parallel along the ultrasound data path. Data is exchanged
between different ones of the second type of integrated circuit 82
for implementing parallel processing, such as for implementing
M-mode or spectral Doppler type imaging. One of the second type of
integrated circuits 82 combines the information from all of the
second type of integrated circuits 82 for outputting a display
image. Alternatively, an additional component combines information
output from the different ones of the second type of integrated
circuits 82. In alternative embodiments, both low and high cost
diagnostic ultrasound systems use a single one of the second type
of integrated circuits 82.
[0054] The ultrasound data path provided by the first type of
integrated circuit 80, the second type of integrated circuit 82 and
any other integrated circuits usable in multiple systems has
different complexity levels. For example, FIG. 2 represents a lower
complexity level than FIG. 3. Complexity is provided by increased
bandwidth, performance of additional functions, ability to operate
with additional inputs, ability to operate with additional outputs,
resolution, or other factors. In general, the complexity level is
associated with cost. FIG. 3 represents an increased complexity for
a higher cost medical diagnostic ultrasound imaging system, and
FIG. 2 represents a lower complexity level associated with a lower
cost medical diagnostic ultrasound imaging system. The lower
complexity level is associated with a fewer number of the first
type of integrated circuits 80 and/or the second type of integrated
circuits 82. Different housings may be provided, such a cart based
system for the more complex level of the ultrasound data path and a
portable (e.g., hand-held or carryable) housing for the lower
complexity level system. For more complex ultrasound data path,
additional types of integrated circuits or other components not
included in the low cost medical diagnostic ultrasound system are
provided. For example, the wavefront calculator 84 shown in FIG. 4
is included in a higher cost medical diagnostic ultrasound imaging
system but not in a lower cost medical diagnostic ultrasound
imaging system. The number of the first type of integrated circuit
80 or receive beamformer components may be greater for more complex
ultrasound data paths, such as associated with operation with a
greater number of simultaneous receive beams.
[0055] FIGS. 1, 2 and 3 show two or three different levels of
complexity. For example, FIG. 2 is a general representation of the
system of FIG. 1. More than two levels of complexity and associated
cost for ultrasound systems may be provided. For example, a middle
cost medical diagnostic ultrasound system with a mid-complexity
level of the ultrasound data path is provided. Any of the various
features described above may be provided in the same, or different
level than the low and high complexity level ultrasound data paths.
For example, a fewer number of the first type of integrated
circuits 80 are provided in the middle cost system than for a high
cost system of FIG. 3, and a greater number are provided than for
the low cost system of FIG. 2.
[0056] FIG. 6 shows a receive beamforming ASIC with a channel
input, a channel output, a beamsum input and a beamsum output.. The
channel input connects with the beamsum output and the channel
output. The channel output outputs the input signal without
alteration. The beamsum output connects with a beamformer and
summer for combining the channel input signals with the beamsum
input signals. The ASICs are combined beamsum input to output for
implementing beamforming in a simple or lower cost system. To
provide formation of multiple beams using the same input channels,
the ASICs are combined so that additional beams are formed from
connection with the channel output (i.e., multiple columns of
ASICs). The arrangement of FIG. 6 may be used in addition to the
arrangement of FIG. 3.
[0057] In one example price distribution for medical diagnostic
ultrasound systems, five different platforms using different
selections of the same integrated circuits 80, 82 are provided. For
example, table 1 shows five different levels of complexity and
associated cost of medical diagnostic ultrasound imaging systems.
TABLE-US-00001 TABLE 1 1st price segment 2nd 3rd 4th 5th TX/RX
Channels 192/192 96/96 64/64 48/48 16/32 Color/flow Y Y Y Y (power)
PW/CW/Aux CW Y/Y/Y Y/Y/Y Y/Y/Y Y/Y/Y N/Y/N Parallel RX beams 4 4 2
2 1 Probe elements 192 192 192 128 64 Ports-transducer 3 3 3 1/2 1
connectors Pixels 1152/864 920/690 720/540 720/540 290/216 Power
1200 W 800 W 300 W 100 W 5 W
[0058] In table 1, the fifth price segment is associated with a
hand-held system. For the difference in the number of transmit and
receive channels for the fifth price segment system, the partial
beamformer, time division multiplexing, or subarray mixing are used
to allow 16 analog-to-digital converters to cover 32 elements.
Color or flow indication with a Y for yes indicates velocity, power
and/or variance. The number of parallel receive beams indicate the
maximum number of substantially simultaneously formed receive
beams. The probe elements number indicates a maximum number of
elements within a probe that may be connected with the system. For
the fourth price segment system, the number of ports or transducer
connectors varies depending on housing options, such as two ports
being available with a mobile cart and only one port being
available with a non-cart (e.g. suitcase size portable) system. The
number of pixels indicates a resolution for display. Other
distribution of features and price segments may be provided than
shown in table 1.
[0059] FIG. 5 shows one embodiment of a method for scalable
manufacturing of medical diagnostic ultrasound imaging systems.
Additional or different acts may be provided than shown in FIG. 5.
For example, additional types of systems with different levels of
complexity are assembled.
[0060] In act 94, a set of application specific integrated circuit
chips is provided. Different types of chips have different
ultrasound functions. The set is provided for mix and match
assembling of different ultrasound systems.
[0061] In act 96, a first type of medical diagnostic ultrasound
imaging system is assembled. A set of chips from the mix and match
set are connected or assembled together. For example, the low cost
medical diagnostic ultrasound system shown in FIG. 2 is assembled
from the two, at least in part, types of integrated circuits 80,
82. For low cost systems, a fewer number of beamforming type
circuits are assembled together.
[0062] In act 98, a higher cost medical diagnostic ultrasound
system is assembled from the same types of application specific
integrated circuit chips. For example, the system shown in FIG. 3
is assembled. More of the beamforming type of integrated circuits
are provided. Additional integrated circuits not in a lower end
system may be provided, such as including the wavefront calculator
84 shown in FIG. 4.
[0063] By using a same collection of types of integrated circuits,
the integrated circuit chips used for the different types of
medical diagnostic ultrasound systems include common integrated
circuit chips. For example, those systems use the same integrated
receive beamformer and integrated detection type chips. To further
differentiate the systems, the application specific integrated
circuit chips used in the different systems may operate at
different power levels, with different numbers of maximum
simultaneous receive beams or other features or functions.
[0064] The same types of application specific integrated circuit
chips may be assembled into yet other medical diagnostic ultrasound
imaging systems. Different numbers of the same chips or different
combinations of the provided application specific integrated
circuit chips are connected together for implementing different
medical diagnostic ultrasound imaging systems or platforms. The
same types of chips are used in different systems, such as
providing for two, three, four or more types of common application
specific integrated circuit chips in different ultrasound imaging
platforms.
[0065] While the invention has been described above by reference to
various embodiments, it should be understood that many changes and
modifications can be made without departing from the scope of the
invention. It is therefore intended that the foregoing detailed
description be regarded as illustrative rather than limiting, and
that it be understood that it is the following claims, including
all equivalents, that are intended to define the spirit and scope
of this invention.
* * * * *