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Claims  |
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What we claim is:
1. A compound mode ultrasound diagnosis apparatus comprising:
transducer means for radiating ultrasound beams toward an object under
examination and for receiving ultrasound echoes reflected therefrom;
means for processing the ultrasound echoes so as to obtain B-mode
ultrasound echo signals and M-mode ultrasound echo signals;
digital scan converter means for converting the echo signals into video
signals, said digital scan converter means including
(a) analog-to-digital converter means for converting the echo signals into
B-mode digital ultrasound echo data and M-mode digital ultrasound echo
data,
(b) memory means having first and second memory areas for storing said
B-mode digital ultrasound echo data and said M-mode digital ultrasound
echo data, respectively,
(c) write control means for writing said B-mode digital ultrasound echo
data and said M-mode digital ultrasound echo data into first and second
memory areas, respectively,
(d) read control means for reading out said B-mode digital ultrasound echo
data and said M-mode digital ultrasound echo data and
(e) digital-to-analog converter means for converting the B-mode and M-mode
digital ultrasound echo data readout from said memory means into said
video signals; and
means for displaying the video signals.
2. A compound mode ultrasound diagnosis apparatus according to claim 1,
wherein said transducer means includes means for producing control pulses,
a pulser unit receiving said control pulses for producing ultrasound
driving pulses delayed a predetermined time with respect to said control
pulses, and a probe having a phased array ultrasound transducer for
transmitting said ultrasound driving pulses and for receiving said
ultrasound echoes;
said processing means includes means for amplifying the ultrasound echoes
received by said probe, means for delaying the amplified ultrasound echoes
by predetermined time intervals, and means for combining said delayed
ultrasound echoes to synthesize the B-mode ultrasound echo signals and the
M-mode ultrasound echo signals;
said memory means of said digital scan converter includes a first line
buffer memory for making the digital data received from the
analog-to-digital converter correspond to one ultrasound beam, and a frame
memory for sequentially storing signals output from said first line buffer
memory; and
wherein said digital scan converter means further includes control means
for generating timing signals delivered to said write and to said read
control means to effect transfer of data to and from said frame memory.
3. A compound mode ultrasound diagnosis apparatus comprising:
transducer means for radiating ultrasound beams toward an object under
examination and for receiving ultrasound echoes reflected therefrom;
means for processing the ultrasound echoes so as to obtain B-mode
ultrasound echo signals and Doppler ultrasound echo signals;
digital scan converter means for converting the echo signals into video
signals, said digital scan converter means including
(a) analog-to-digital converter means for converting the ultrasound echo
signals into B-mode digital ultrasound echo data and Doppler digital
ultrasound echo data,
(b) memory means having first and second memory areas for storing said
B-mode digital ultrasound echo data and said Doppler digital ultrasound
echo data,
(c) write control means for writing said B-mode digital ultrasound echo
data and said Doppler digital ultrasound echo data into first and second
memory areas, respectively,
(d) read control means for reading out said B-mode digital ultrasound echo
data and said Doppler digital ultrasound echo data in accordance with a
television format, and
(e) digital-to-analog converter means for converting the B-mode and Doppler
digital ultrasound echo data read out from said memory means into said
video signals; and
means for displaying the video signals on a television screen.
4. A compound mode ultrasound diagnosis apparatus according to claim 3,
wherein said transducer means includes means for producing control pulses,
a pulser unit for producing ultrasound driving pulses having predetermined
time delays with respect to said control pulses, a first probe having a
phased array ultrasound transducer for transmitting said ultrasound
driving pulses and for receiving ultrasound echoes corresponding thereto,
a Doppler pulser for producing Doppler driving pulses in accordance with
said control pulses, a Doppler probe for transmitting said Doppler driving
pulses and for receiving Doppler echoes corresponding thereto, and means
for supporting said Doppler probe;
said processing means includes an amplifier which amplifies the ultrasound
echoes received by said first probe, means for delaying the amplified
ultrasound echoes by predetermined time intervals, synthesizing means for
synthesizing the delayed ultrasound echoes to form said B-mode ultrasound
echo signals, a Doppler amplifier for amplifying the Doppler echoes
received by said Doppler probe, means for forming phase detected signals
from the amplified Doppler echoes, filter means for filtering the phase
detected signals, means for sample-holding signals outputted from said
filter means to produce Doppler deviation signals in accordance with a
location for detecting Doppler deviation, and a fast Fourier transform
circuit for converting the Doppler deviation signals into frequency
distribution signals, whereby said B-mode ultrasound echo signals and said
frequency distribution signals are written into said first and second
memory areas of said memory means, respectively, by said digital scan
converter means.
5. A compound mode ultrasound diagnosis apparatus according to claim 4,
wherein said Doppler probe supporting means includes means for generating
marker signals representative of a direction in which said Doppler pulses
are transmitted from said Doppler probe and the Doppler detecting
location, said marker signals being displayed together with the video
signals corresponding to the B-mode digital ultrasound echo data.
6. A compound mode ultrasound diagnosis apparatus according to claim 4,
wherein said digital scan converter means includes means for selectively
converting said B-mode ultrasound echo signals and said Doppler echo
signals into digital signals, a first line buffer memory for grouping the
digital signals corresponding to one ultrasound beam, a frame memory for
sequentially storing signals output from said first line buffer memory,
means for converting data read out from said frame memory into an analog
signal, and means for generating timing signals for controlling write and
read operations of said frame memory.
7. A compound mode ultrasound diagnosis apparatus according to claim 4,
wherein said supporting means has an archlike portion for producing a
predetermined driving beam direction as said Doppler probe is moved along
said supporting means.
8. A compound mode ultrasound diagnosis apparatus according to claim 3,
wherein said transducer means includes means for producing control pulses,
a pulser unit receiving said control pulses for producing ultrasound
driving pulses delayed a predetermined time with respect to said control
pulses, and a probe having a phased array ultrasound transducer for
transmitting said ultrasound driving pulses and for receiving said
ultrasound echoes;
said processing means includes means for amplifying the ultrasound echoes
received by said probe, means for delaying the amplified ultrasound echoes
by predetermined time intervals, and means for combining the delayed
ultrasound echoes so as to synthesize the B-mode ultrasound echo signal
and the Doppler ultrasound echo signals;
said memory means of said digital scan converter includes a first line
buffer memory for making the digital data received from the
analog-to-digital converter correspond to one ultrasound beam, and a frame
memory for sequentially storing signals output from said first line buffer
memory; and
wherein said digital scan converter means further includes means for
generating timing signals delivered to said write control means and to
said read control means to effect transfer of data to and from said frame
memory.
9. A compound mode ultrasound diagnosis apparatus comprising:
transducer means for radiating ultrasound beams toward an object under
examination and for receiving ultrasound echoes reflected therefrom;
means for processing the ultrasound echoes to obtain ultrasound echo
signals corresponding to distinct scan modes;
digital scan converter means for converting the echo signals into video
signals, said digital scan converter means including
(a) analog-to-digital converter means for converting said ultrasound echo
signals into at least two distinct sets of digital ultrasound echo data,
each set of said digital data corresponding to a different one of said
distinct scan modes,
(b) memory means having a plurality of distinct memory areas for storing
said at least two sets of digital ultrasound echo data,
(c) write control means for respectively writing said at least two sets of
digital ultrasound data into said memory means, each set of said digital
data being stored together in a distinct memory area,
(d) read control means for reading out said at least two sets of digital
ultrasound data in accordance with a television format,
(e) digital-to-analog converter means for converting the digital ultrasound
data read out from said memory means into video signals; and
means for displaying the video signals on a television screen, so as to
form noninterlaced separate images corresponding to said distinct scan
modes.
10. A compound mode ultrasound diagnosis apparatus according to claim 9,
wherein said transducer means includes means for producing control pulses,
a pulser unit for receiving said control pulses and for producing
ultrasound driving pulses delayed a predetermined time with respect to
said control pulses, and a probe having a phased array ultrasound
transducer for transmitting said ultrasound driving pulses and for
receiving said ultra sound echoes;
said processing means includes means for amplifying the ultrasound echoes
received by said probe, means for delaying the amplified ultrasound echoes
by predetermined time intervals, and means for combining the delayed
ultrasound echoes so as to synthesize said ultrasound echo signals
corresponding to said distinct scan modes;
said memory means of said digital scan converter including a first line
buffer memory for making the digital data received from the
analog-to-digital converter means correspond to one ultrasound beam, and a
frame memory for sequentially storing signals output from said first line
buffer memory; and
wherein said digital scan converter means further includes means for
generating timing signals delivered to the write control means and to the
read control means to effect transfer of data to and from said frame
memory. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention relates to a compound mode ultrasound diagnosis
apparatus capable of concurrently displaying at least two different kinds
of ultrasound images or data on a single TV monitor screen.
In diagnosing a heart of an unborn child, for example, by means of the
ultrasound diagnosis apparatus, commonly used is a method in which a
B-mode image on real time is displayed on a display screen by using a high
speed electronic scanning system while at the same time data on a desired
location or locations in the B-mode image are sampled so that an M-mode
image is displayed on another separate display screen. For displaying the
B-mode image, an X-Y monitor of the short storage type, is employed, since
the image formed through a high speed electronic scanning must be
displayed on the real time basis. For the M-mode image, an X-Y monitor of
the storage type is used since the image formation is made at relatively
low speed.
A correlation between an instantaneous motion of the whole heart and a
motion of a particular portion of the heart is very useful for the heart
diagnosis of an unborn child. It is for this reason that the concurrent
display of the B-mode image on the real time basis and the M-mode image is
employed. For ease of grasping the correlation between the B- and M-mode
images, photographing simultaneously both the images, and recording the
images by a video tape recorder, it is desirable that both images be
concurrently displayed side by side on the same screen, not on separate
screens.
To meet the desire of the concurrent display of both the images has been
considered difficult in that there is a difference between the
characteristics of the two images or data required for the display, and
that a complicated scanning operation is necessary for realizing the
concurrent display of the different images on a single screen.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a compound
mode ultrasound diagnosis monitor apparatus capable of concurrently
displaying at least two kinds of ultrasound images or data on a screen of
a monitor display in a simple manner.
According to one aspect of this invention, there is provided a compound
mode ultrasound diagnosis apparatus comprising:
a phased array transducer for radiating at least two kinds of ultrasound
beams toward an object under examination and for receiving ultrasound echo
echoes reflected therefrom;
a circuit arrangement for processing the ultrasound echo so as to obtain
two kinds of ultrasound echo signals;
a digital scan converter for converting the echo signals into television
video signals; and
a television monitor for displaying the television video signals;
the digital scan converter including an analog-to-digital converter for
converting the ultrasound echo signals into two kinds of digital
ultrasound echo data,
a frame memory for storing the two kinds of digital ultrasound echo data,
a write control circuit for respectively writing the two kinds of digital
ultrasound data into first and second memory areas of the frame memory,
a read control circuit for reading out the two kinds of digital ultrasound
data in accordance with a television format, and
a digital-to-analog converter for converting the digital ultrasound data
read out from the frame memory into television video signals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a scanning method to take a B-mode (tomogram) image and
an M-mode image of a human body by using an electronic linear scan type
ultrasound probe;
FIG. 2 is a memory format illustrating a state that the data obtained by
the scanning method shown in FIG. 1 are stored in a frame memory;
FIG. 3 is a block diagram of a circuit arrangement of an embodiment of an
ultrasound diagnosis apparatus according to the invention;
FIG. 4 is a block diagram of a digital scan converter used in the circuit
arrangement shown in FIG. 3;
FIG. 5 is a detailed block diagram of a circuit arrangement of the digital
scan converter shown in FIG. 4 and the associated circuits thereof;
FIGS. 6A to 6D and FIGS. 7A to 7C show timing charts useful for explaining
the operation of the circuit of FIG. 5;
FIG. 8 shows a block diagram of an ultrasound beam steering control
circuit;
FIG. 9 illustrates a method to take a B-mode (tomogram) ultrasound echo and
Doppler ultrasound echo according to another embodiment of the present
invention;
FIG. 10 is a memory format illustrating a state of the data obtained by the
method shown in FIG. 9;
FIG. 11 is a block diagram of a circuit arrangement of another embodiment
of the ultrasound diagnosis apparatus according to the present invention
using the method shown in FIG. 9;
FIG. 12 is a block diagram of the digital scan converter used in the
circuit shown in FIG. 11;
FIGS. 13 and 14 are timing charts for explaining the operation of the
circuit shown in FIGS. 11 and 12; and
FIG. 15 shows a part of the circuitry of the digital scan converter of FIG.
12.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In a scanning method used in an embodiment of the compound mode ultrasound
diagnosis apparatus according to the invention, schematically illustrated
in FIG. 1, an electronic scanning probe 11 is used in contact with the
surface of a human body 12 at the time of diagnosis. The electronic
scanning probe 11, composed of a phased array ultrasound transducer, is
coupled with a main unit of the dual mode ultrasound diagnosis apparatus,
through a line 13. The present embodiment is so constructed as to
concurrently display on a single TV monitor screen a B-mode real time
tomogram of a heart 14 in the human body 12 formed by using the electronic
scanning probe 11 and M-mode image data formed by sampling an ultrasound
echo. The M-mode image is known as a sampling ultrasound cardiogram
(briefly called a sampling U.C.G. or a simultaneous U.C.G.).
In FIG. 1, driving electric pulse signals delivered through the line 13
from the main unit of the ultrasound diagnosis apparatus (not shown) are
supplied to the ultrasound transducers within the probe 11 in a given
order. The probe 11 sequentially radiates toward the heart 14, 128
ultrasound beams B.sub.1, B.sub.2, . . . B.sub.i-1, B.sub.i, B.sub.i+1, .
. . B.sub.127, B.sub.128, for example. Every time each of the respective
beams B.sub.i (i=1, 2, 3, . . . 128) is radiated, the probe 11 is switched
from a radiation mode to a receiving mode. Under this condition,
ultrasound echoes reflected from the inside of the human body 12 are
converted, by the ultrasound transducers in the probe 11, into echo
signals which in turn are sent through the line 13 to the main unit of the
ultrasound diagnosis apparatus. The echo signals are properly processed in
the main unit to be transformed into echo data which are then stored in a
frame memory 15 shown in FIG. 2.
The frame memory 15 having a memory capacity of one frame of the TV monitor
screen includes a first memory area 15a corresponding to the left half of
the screen of the monitor and a second memory area 15b corresponding to
the right half of the screen. Assuming now that the one frame of the TV
monitor is formed of 256.times.512.times.4 bits. RAM (random access
memory) composed of an MOS memory or a bipolar memory may be used as the
frme memory. The first memory area 15a stores the data of the B-mode real
time tomogram. The second memory area 15b stores the data of the M-mode
image. The first memory area 15a has 128 X addresses, BR.sub.1, BR.sub.2,
. . . BR.sub.i, . . . BR.sub.128. The number of the memory address
locations is the same as that of the beams B.sub.1, . . . B.sub.i, . . .
B.sub.128. The number of the Y-address locations is 512. The X-,
Y-addresses are designated by outputs of a frame memory address generator.
The echo data, obtained through one scanning by a sequence of the beams
B.sub.1 to B.sub.128, are written in turn into the memory locations
BR.sub.1, BR.sub.2, . . . BR.sub.128 by the X-addresses. At each of the
memory locations BR.sub.1 to BR.sub.128 the data are written into the
first memory area 15a from the upper end to the lower end thereof in the
figure by the Y-addresses. In the B-mode real time scanning, the
repetition rate of the ultrasound beam scanning is several tens per
second, at least ten and several repetitions per second in order to obtain
effective diagnostic information. The data stored in the memory area 15a
in the frame memory 15 are updated substantially on a real time basis.
Meanwhile, the M-mode data can be obtained by using the sampling U.C.G.
method which will be described in detail hereinafter. The M-mode data are
formed by sampling an ultrasound echo at a predetermined position every
time 8 ultrasound beams, for example, are radiated. This will be described
by referring to FIG. 1 in which after 7 ultrasound beams B.sub.1, B.sub.2,
. . . B.sub.7 are each sequentially radiated an ultrasound beam B.sub.i is
radiated at the predetermined position. Then, 7 ultrasound beams B.sub.8,
B.sub.9, . . . B.sub.14 are each sequentially radiated and the ultrasound
beam B.sub.i is again radiated at the predetermined position. In this
manner, many sets of 8 ultrasound beams are radiated in turn and
ultrasound echo signals of the ultrasound beams B.sub.i are processed to
obtain M (U.C.G.)-mode image data. The M-mode image data thus obtained are
written into the right half memory area 15b of the frame memory 15 in the
similar manner as the B-mode image data in which the M-mode image data are
written into the memory locations MR.sub.1, MR.sub.2, . . . MR.sub.128 in
the order under the designation of the X-addresses and at each of the
locations MR.sub.1 to MR.sub.128 the M-mode data are written from the
upper portion to the lower portion thereof under the designation of the
Y-addresses.
The B-mode image data and the M-mode image data, which are stored in the
frame memory 15, are all together converted into a television format (a
standard system of the television scanning), for example, and then are
simultaneously displayed on a single screen of the monitor display, side
by side. For this reason, the B-mode image and the M-mode image on the
monitor screen substantially correspond to the memory format shown in FIG.
2. To display the data stored in the frame memory 15 on the monitor
screen, a digital scan converter is used, which will be described in
detail hereinbelow.
The arrangement of the embodiment of the ultrasound diagnostic apparatus of
the invention will be described by referring to FIGS. 3 and 4. As shown in
FIG. 3, the probe 11 shown in FIG. 1 is an array of ultrasound transducers
11a, 11b, . . . 11k, (k being an integer), which are disposed closely to
one another in practical use, in order to improve a resolution of the
images formed. The ultrasound transducers 11a, . . . 11k, respectively,
are connected to pulsers 22a, 22b, . . . 22k, (k being an integer), in a
pulser unit 22 or preamplifiers 23a, 23b, . . . 23k in a receiving unit
23, by way of switches 21a, 21b, . . . 21k for switching between
transmission and reception. In the transmission mode, the switches 21a to
21k are so switched as to transmit electric pulses from the pulsers 22a to
22k to the transducers 11a to 11k. In the receiving mode, those switches
21a to 21k are switched so that the echo signals derived from the
transducers 11a to 11k are supplied to the preamplifiers 23a to 23k.
The pulser unit 22 is comprised of pulsers 22a to 22k and a plurality of
delay lines 220a, 220b, . . . 220k, (k being an integer), connected to the
input sides of the pulsers 22a to 22k. Control pulses generated from a
control pulse generator 24 are commonly supplied to the inputs of the
delay lines 220a to 220k. The control pulses supplied to the delay lines
220a to 220k, respectively, are delayed by given time intervals and
supplied as driving pulses to the pulsers 22a to 22k. In response to the
driving pulses, the pulsers 22a to 22k generate transducer driving pulses.
The pulser unit 22 is controlled by a raster address signal delivered from
a raster address generator 25 driven by the control pulse generated from
the control pulse generator 24, so that the control pulse is supplied to
the delay lines 220a to 220k so as to effect given beam scanning and beam
focusing. The method to scan and focus the ultrasound beams by using the
raster address signal is well known, and no further explanation will be
given here.
The receiving unit 23 is comprised of preamplifiers 23a to 23k, (k being an
integer), for amplifying the echo signals delivered from the transducers
11a to 11k through the switches 21a to 21k, delay lines 230a, 230b, . . .
230k, (k being an integer), to delay by given time period the echo signals
amplified by the preamplifiers 23a to 23k, and an adder 231 for summing
the output signals from the delay lines 230a to 230k. The receiving unit
23 is also supplied with the raster address signal from the raster address
generator 25, as in the case of the pulser unit 22. With the raster
address signal received, the focusing and summing of the echo beams are
performed corresponding to the beam scannings in the transmission mode.
The scanning and focusing of the echo beams by using the raster address
signal are easily performed by a well known ultrasound signal processing
method, and no detailed description thereof will be given here.
The summed or synthesized echo signal derived from an output terminal of
the adder 231 is amplified and detected by an amplifier/detector circuit
26 of which the output is supplied to one of the input terminals of a
digital scan converter 27. The digital scan converter 27, containing the
frame memory 15 shown in FIG. 2, converts the summed echo signal into a
television format signal. The television format signal converted is
supplied to a television monitor 28 where it is visualized. The conversion
of the summed echo signal into the television format signal is performed
under control of the control pulse and the raster address signal applied
from the generators 24 and 25 to the digital scan converter 27. A line
scan recorder 29 may be connected to the output of the amplifier/detector
circuit 26.
An example of the digital scan converter 27 will be described by referring
to FIG. 4. The summed echo signal outputted from the amplifier/detector
circuit 26 in FIG. 3 is converted into digital ultrasound echo data in an
analog-to-digital (A/D) converter 27a. The digital ultrasound echo data
corresponding to one ultrasound beam, for example, the beam B.sub.1 in
FIG. 1, is stored in an input line buffer memory 27b. The digital
ultrasound echo data for one ultrasound beam temporarily stored in the
line buffer memory 27b are sequentially loaded into the memory locations
of the frame memory 15 in address sequence under control of the timing
signal supplied from the timing signal generator 27c. As a matter of
course, the A/D converter 27a and the line buffer memory 27b also operate
under control of the timing signal generator 27c. The timing signal
generator 27c generates signals of given timing, in accordance with the
control pulse from the control pulse generator 24 and the raster address
signal from the raster address generator 25 shown in FIG. 3.
While the B-mode image data are loaded into the first memory area 15a, an
M-mode ultrasound echo signal of the beam B.sub.i in FIG. 1 is sampled and
the sampled (M-mode image) data are sequentially stored into the memory
area 15b of the frame memory 15. The data stored in the frame memory 15
are read out in accordance with the television format. The data are loaded
to an output line buffer memory 27d and the data read out therefrom are in
turn supplied to a digital-to-analog (D/A) converter 27e. The D/A
converter 27e converts the data into an analog signal and applies the
obtained analog signal as a video signal to the TV monitor 28.
Turning now to FIG. 5, there is shown in block form the detail of the
digital scan converter shown in FIG. 4 and the associated circuit thereof.
As shown, the timing signal generator 27c is comprised of a rate pulse
generator 24, a sampling clock pulse generator 111, an input buffer memory
address generator 112, an input buffer memory selector 113, a frame memory
address generator 114, a read/write mode selector 115, an output buffer
memory address generator 116, an output buffer memory selector 117 and a
basic pulse generator 132. The timing signal generator 27c becomes
operative in synchronism with the basic pulse from the basic pulse
generator 132. The ultrasound echo signals are converted into digital
ultrasound data in the A/D converter 27a which have 4 bits per pixel in
accordance with the sampling clock pulse generated from the sampling clock
pulse generator 111. The ultrasound image data are supplied through a
switching circuit 118 to the line buffer memory 27b where the data are
temporarily stored.
The line buffer memory 27b is comprised of two input buffer memories 120
and 121, each of which has a memory capacity of 512.times.4 bits and
stores the ultrasound image data obtained from an ultrasound echo signal.
The input buffer memories 120 and 121 are switched to be alternately in
the write mode and the read mode under control of the switching circuits
118 and 119 which are alternately switched by the output signal from the
input buffer memory selector 113. An inverter 122 inverts the output
signal of the input buffer memory selector 113 which in turn is applied to
the switching circuit 119. In a state of the line buffer memory 27b as
illustrated, the input buffer memory 121 is in the write mode and stores
the ultrasound image data of the ultrasound beam B.sub.i while the input
buffer memory 120 is in the read mode and provides the ultrasound image
data of the ultrasound beam B.sub.i-1 to the frame memory 15. The
read/write address of these input buffer memories 120 and 121 are supplied
from the input buffer memory address generator 112. In the frame memory
15, the B-mode image data and the M-mode image data are both written
thereinto in the same direction as that of the scan of each ultrasound
beam in accordance with an X-address and a Y-address, which are supplied
from the frame memory address generator 114.
Assume now that the maximum diagnostic depth is 18 cm, the propagating
speed of the ultrasound in the human body is 150,000 cm/sec, and the rate
blanking period is 40 .mu.sec. On this assumption, the period of the
ultrasound beam radiation, i.e., the repetitive period of the rate pulse,
is 274 .mu.sec (=40 .mu.sec+13 .mu.sec/cm.times.18 cm). Here, 13 .mu.sec
is the propagating time of the ultrasound in the ultrasound diagnostic
depth of 1 cm. When the ultrasound reflection is considered, the
ultrasound propagates 2 cm and hence 2 cm/15.times.10.sup.4
cm/sec.apprxeq.13 .mu.sec.
The rate blanking pulse and the ultrasound echo signal take waveforms as
shown in FIGS. 6A and 6B, respectively. During the repetitive period of
the control pulse, the data in one column of the frame memory, i.e., the
data of 512 pixels, must be written into the frame memory 15. Since the
memory cycle time of the frame memory 15 is very short, the stored image
data can be read out approximately one time during a period that the data
of 3 pixels are written into the frame memory. Since the data of 512
pixels of one column of the frame memory may be loaded within 274 .mu.sec,
the data of 3 pixels may be loaded within 1,605 nsec. Accordingly, the
read/write mode selector 115 produces three write enable pulses and one
read enable pulse during the period of 1,605 nsec, as shown in FIGS. 6C
and 6D. The read enable pulse has a repetitive period of 1,605 nsec.
In order to display the image data on the TV monitor, within 63.5 .mu.sec
which is equal to the period of the one horizontal synchronizing pulse,
the image data of 256 pixels must be read out from the frame memory 15 and
must be stored into the output buffer memory 27d. There are 256 pixels in
a television raster direction (an X-axis direction of the frame memory 15)
orthogonal to the scan direction for the image data writing. Accordingly,
248 nsec is required for 1 pixel, so that the image data of 8 pixels in
the television raster direction are simultaneously read out from the frame
memory 15 to be transferred to the output buffer memory 27d. The address
of the frame memory 15 is designated by the output pulse of the frame
memory address generator 114, and a read/write enable pulse is produced by
a read/write mode selector 115.
In connection with the address of the frame memory 15, the sampling U.C.G.
for obtaining the M-mode image signal will be described in detail. As
previously stated, the sampling U.C.G. may be obtained from the ultrasound
echo signal at the location of the ultrasound beam B.sub.i (indicated by a
thick line in FIG. 1), for example, every time the control pulse generator
24 produces 8 control pulses. The control pulse is generated from the
control pulse generator 24 every 274 .mu.sec, as shown in FIG. 7A. Since 7
out of every 8 control pulses of the control pulse train are used for the
B-mode control pulses and the remaining one control pulse for the M-mode
control pulse, the ultrasound beam steering control may be made such that
the scan is made of the ultrasound beams B.sub.1, B.sub.2, . . . , B.sub.7
and the ultrasound beam B.sub.i is produced, and then the scan is made of
the succeeding ultrasound beams B.sub.8, B.sub.9, . . . , B.sub.14 and the
ultrasound beam B.sub.i is again produced.
FIG. 8 is an ultrasound beam steering control circuit arrangement. In the
circuit arrangement, the control pulse train from the control pulse
generator 24 is divided by a 1/8 divider 123, thereby to produce the
M-mode control pulse. The M-mode control pulse is in turn applied to the
inhibit input terminal of an AND gate 124 while the control pulse is
applied to the other input terminal of the AND gate 124. As a result, the
B-mode control pulses are produced. Such a circuit arrangement that the
ultrasound beams B.sub.1, B.sub.2, . . . , B.sub.7 are radiated in
accordance with the B-mode control pulses and the ultrasound beam B.sub.i
at a given location is radiated in accordance with the M-mode control
pulses, is well known and therefore the explanation of the circuit
arrangement will be omitted. The M-mode control pulse outputted from the
1/8 divider 123 is delayed by 274 .mu.sec in a delay circuit 125 and then
is applied to a frame memory address generator 114. It is for this reason
that since the ultrasound image data read out from the input buffer memory
27b is that formed by the ultrasound beam before one rate pulse, the
M-mode image data must be written into the memory area 15b of the frame
memory 15 after it is delayed by approximately 274 .mu.sec of one control
pulse period.
The output signal of the raster address generator 25 (FIG. 3) is supplied
to the frame memory address generator 114 to know which ultrasound beam is
radiated mainly in order to obtain the ultrasound image data of the
B-mode. A sweep control circuit 126 is provided to supply an M-mode sweep
control signal to the frame memory 15 which is in synchronism with the
rate pulse.
Generally, the M-mode image is used to observe a motion of the valve in the
heart with respect to time which is relatively of a slow speed.
Accordingly, it is desirable to observe the motion of the valve over 1
second or 2 seconds, for example. In the sampling U.C.G., the time taken
for the M-mode image to be written into the memory area 15b is 281.6 msec
(=8 control pulses/sec.times.275 .mu.sec.times.128 pixels). Therefore,
when the sweep time of 1 .mu.sec is set up by an operator, it is necessary
to write the M-mode image in the memory area 15b every approximately 4
M-mode ultrasound beams under control of the output from the sweep control
circuit 126. Since the M-mode data may be read out from the frame memory
15 in accordance with the manner previously described, the CRT display
allows the M-mode image with the sweep time of one second to be displayed,
so that the operator simultaneously observes the B-mode image in
connection with the M-mode image for diagnosis. For further detailed data,
a hard copy is available by the line scan recorder 29 which records the
ultrasound echo signals including the M-mode echo signals as they are.
The output line memory 27d has output buffer memories 127 and 128 each for
storing the video data of one horizontal synchronism pulse period of the
TV monitor 28. The output video data of the frame memory 15 are
alternately written into the output buffer memories 127 and 128, through a
switching circuit 129. The video data stored are alternately read out from
the output buffer memories 127 and 128 into a digital-to-analog converter
27e, through a switching circuit 130. The switching circuits 129 and 130
are controlled by the output buffer memory selector 117. Incidentally, the
output signal of the output buffer memory selector 117 is inverted by an
inverter 131 and supplied to the switching circuit 130. The addresses of
the output buffer memories 127 and 128 are designated by the output buffer
memory address generator 116. Note here that the address designation must
be made such that in the write mode the data of 8 pixels are
simultaneously written while in the read mode the data are sequentially
read out for each pixel and supplied to the digital-to-analog (D/A)
converter 27e where in turn the digital data are converted into analog
video signals. The switching circuits 129 and 130 are switched every one
horizontal synchronizing period 63.5 .mu.sec and the output buffer
memories are switched at the period to alternately be in the read and
write modes. The output pulse of the control pulse generator 132 is also
supplied to a TV synchronizing pulse generator 134 where the horizontal
synchronizing pulse and the vertical synchronizing pulse are generated.
The analog video signals of the D/A converter 27e and the output of the TV
synchronizing pulse generator 134 are synthesized in a composite video
signal generator 135 to produce a TV video signal, which is provided to
the TV monitor 28. It will be seen that upon designation of the address of
the frame memory address generator 114, the ultrasound image may be
displayed by the TV monitor 28 both in the interlace raster scan and in
the non-interlace raster scan modes.
In this way, the present embodiment simultaneously displays the M-mode
image and the B-mode image on the screen of the television monitor.
Therefore, the comparison of both the images is easy and the correct
diagnosis is ensured. Particularly, for the diagnosis by using a
photograph taken of the ultrasound images, the ultrasound diagnosis
apparatus of the embodiment is very effective, since the photograph has
the B-mode image and the M-mode image, which are taken at the same timing.
Although not referred to in the above description, the M-mode marker
representing a location for collecting the M-mode image data may be used
in the B-mode image, as in the case of this type of the device capable of
doing the sampling U.C.G. display.
As described above, the B-mode image and the M-mode image obtained by using
the same electronic linear scanning probe are stored into the memory areas
15a and 15b of the frame memory 15. Those are together read out and are
displayed side by side on the single TV screen. The other methods
available for obtaining the B-mode image data are an electronic sector
scan, a mechanical high speed scan, and a contact compound mechanical
scan. In addition, an independent single probe for obtaining M-mode image
data may be placed at a desired position for sampling U.C.G.
Images other than the M-mode image and the B-mode image may be stored in
the frame memory and displayed side by side on the TV monitor screen.
Alternatively, the B-mode image data previously obtained is prestored in
the first memory area while the image data formed on the real time basis
are stored into the second memory area. The image data thus stored are
used for the concurrent display. As a matter of course, the memory
capacity of the frame memory is not limited to that of one frame but may
be more than that.
Turning now to FIG. 9, there is shown diagrammatically another embodiment
of a compound mode ultrasound diagnosis apparatus to obtain the B-mode
image by an electronic scanning probe 11 and a Doppler ultrasound echo by
a single probe 32. In the description to follow, like reference numerals
are used to designate like or substantially equivalent portions in FIGS. 1
to 8. The ultrasound Doppler data are useful for measuring velocity of a
flow of blood. In diagnosing a heart, it is effective to observe the
B-mode image or the M-mode image together with Doppler data. It is
evident, in this case, that the Doppler data are preferably concurrently
displayed, together with the B-mode image or the M-mode image, on the same
screen.
In FIG. 9, the B-mode tomogram of the heart 14 of an unborn child is formed
by using the electronic linear scanning probe 11, as previously stated.
The B-mode tomogram data are stored on the real time basis in the memory
locations BR.sub.1, BR.sub.2, . . . , BR.sub.128 of the memory area 15a of
the frame memory 15 shown in FIG. 10. The memory locations BR.sub.1 to
BR.sub.128 are assigned with addresses corresponding to the ultrasound
beams B.sub.1, B.sub.2, . . . , B.sub.128.
The Doppler data are stored on the real time basis at the locations
DR.sub.1, DR.sub.2, . . . , DR.sub.128 of the memory area 15b of the frame
memory 15. The locations DR.sub.1 to DR.sub.128 are assigned with
addresses corresponding to the ultrasound beams which are projected for
obtaining the Doppler data. Where, the frame memory 15 may be composed of
a random access memory (RAM) with a memory capacity of
256.times.512.times.4 bits like the first embodiment. The memory areas 15a
and 15b have a memory capacity of 128.times.512.times.4 bits,
respectively.
On the side wall of the ultrasound probe 11 in FIG. 9, a side plate 30 is
fixed to which one end of an arched supporting member 31 is fixed. A
Doppler probe 32 is movably mounted on the supporting member 31 and
movably along the surface of the supporting member 31. By moving the
Doppler probe 32 along the supporting member 31, it is possible to adjust
the location and direction of the ultrasound beam DB radiated from the
probe 32 relative to the heart 14. The relative location and direction of
the ultrasound beam DB may easily be found on the basis of the relative
location of the probe 32 to the supporting member 31.
The compound mode display methods using the electronic linear scanning
probe 11 and the Doppler probe 32 are:
(i) The method wherein the B-mode image and the Doppler data are
alternately stored and displayed at short intervals of time. In the
method, compound mode display can be realized substantially on the real
time basis.
When ultrasound beams are alternately radiated from the electronic linear
scanning probe 11 and the Doppler probe 32 every time one control pulse
appears (the repetition pulse period of the control pulse being 274
.mu.sec), the B-mode ultrasound echo and the Doppler echo are obtained
therefrom. These echoes are processed in circuits hereinafter described so
that the B-mode image data and the Doppler data are formed and these data
are respectively stored in the memory areas 15a and 15b. At this time, as
has been described in the first embodiment, while the data are written
into the frame memory 15, the data can be read out of the frame memory 15
in the television format to display on the TV monitor 28 B-mode image and
the Doppler information (frequency spectrum) on a real time basis.
(ii) The B-mode image data obtained by using the ultrasound probe 11 are
stored in the memory area 15a of the frame memory 15 without renewing the
stored data. At this time, only the Doppler data are updated in the memory
area 15b. The B-mode image data are so read out exclusively as to be
displayed freezingly while the Doppler information is displayed on a real
time basis.
To this end, as described in the compound mode display method (i), the
B-mode ultrasound image data and the Doppler data are first stored in the
frame memory 15 on a real time basis. Then, the B-mode data s | | |
