Patent Application
20160143625
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-238641, filed on Nov. 26, 2014, and Japanese Patent Application No. 2015-226812, filed on Nov. 19, 2015, the entire contents of which are incorporated herein by reference.
An embodiment as one aspect of the present invention relates to an ultrasonic probe and an ultrasonic diagnosis apparatus for transmitting/receiving ultrasonic waves.
As a diagnosing method for a breast cancer, a hepatic cirrhosis, a vascular disorder and the like, a method (elastography) for quantifying and visualizing hardness of a tissue such as an organ in a living body from an ultrasonic echo signal instead of palpation by a doctor is known. The elastography is roughly classified into strain detecting elastography and acoustic radiation elastography. The strain detecting elastography presses and releases a body surface from outside the body and quantifies and visualizes relative hardness with respect to peripheral tissues from deformation (strain) of the organ caused by movement of the organ such as a spontaneously working heart and the like.
The acoustic radiation elastography is to transmit ultrasonic waves for excitation having relatively large energy generating an acoustic radiation pressure to a tissue of an organ in a living body and the like from outside the body. The acoustic radiation elastography is to quantify and visualize hardness (modulus of elasticity) of a tissue by calculating a sound speed of a shear wave generated as a lateral wave around the tissue by displacement (vibration) of the tissue.
Among them, in the acoustic radiation elastography, first, a tissue present at an excitation position is displaced by formation of an ultrasonic beam (excitation beam) for excitation by using an ultrasonic transducer unit for a B mode of an ultrasonic probe. Subsequently, by forming an ultrasonic beam (detection beam) for detection at a detection position around the excitation position by using the same ultrasonic transducer unit, a wave crest of the shear wave generated by the displacement of the tissue is detected by a tissue Doppler method or the like.
Then, in the acoustic radiation elastography, by counting traveling time from transmission time of the excitation beam to arrival time at the detection position of the wave crest of the shear wave, a sound speed of the shear wave from the excitation position to the detection position is calculated. Moreover, an average sound speed of the shear wave on the basis of sound speeds from the excitation position to the detection positions is calculated and a relative value of each sound speed to the average sound speed is calculated as information indicating hardness of the tissue.
Since a living body has viscosity, the wave crest of the shear wave becomes dull as it goes away from the excitation position. As a result, according to the prior-art technology, detection accuracy of the wave crest of the shear wave lowers at the detection position away from the excitation position and thus, uniformity of an image quality of the entire elastography image deteriorates.
Thus, in the prior-art technology, such processing is executed that a display range is divided into multiple blocks, and multiple detection positions (blocks) with high detection accuracy of the shear wave are connected so as to generate one sheet of an elastography image. For this purpose, multiple transmission sequences (combination of transmission of a series of excitation pulses and transmission of a series of detection pulses) need to be performed in correspondence with the multiple detection positions and thus, a frame rate of the elastography image and the like lowers for a portion of time required for the multiple transmission sequences. On the other hand, if the number of detection positions is decreased in order to maintain the frame rate, uniformity of the image quality of the elastography image lowers.
Moreover, if the frame rate of the elastography image and the like lowers, real-time properties are lost, and trouble that artifact is generated in the image by movement of the tissue in the living body also occurs.
The problem that the present invention is going to solve is to provide an ultrasonic probe and an ultrasonic diagnosis apparatus being able to generate information to generate an elastography image in time required for the minimum number of times of transmission sequences.
In accompanying drawings,
An ultrasonic probe and an ultrasonic diagnosis apparatus according to a present embodiment will be described by referring to the attached drawings.
The present embodiment provides the ultrasonic probe including: at least one first transducer functioning as a transducer for excitation for executing excitation by an acoustic radiation pressure in an elastography mode; and second transducers functioning as transducers for detection for detecting a shear wave generated by the excitation in the elastography mode.
The ultrasonic probe 11 is detachably connected to the main body 12. The ultrasonic probe 11 includes an ultrasonic transducer unit for excitation (push) in an elastography (acoustic radiation elastography) mode (hereinafter referred to as a “transducer unit 20 for excitation”) and an ultrasonic transducer unit for detection (track) of the elastography mode (hereinafter referred to as a “transducer unit 30 for detection”). The transducer unit 30 for detection is also used for transmission/reception of ultrasonic waves in a B-mode and a Doppler mode.
Here, a structural example when the ultrasonic probe 11 includes one transducer unit 20 for excitation is illustrated in
As illustrated in
Each of the multiple transducers 931s transmits ultrasonic waves for excitation with relatively large energy (sound pressure) generating an acoustic radiation pressure and also transmits/receives ultrasonic waves for detection with relative smaller energy than the ultrasonic waves for excitation.
Moreover, the multiple transducers 931s are also used in the B mode and the like other than the elastography mode. In the B mode, by sequentially switching the position of the ultrasonic beam (scanning line) for the B mode to the first direction, a still image can be also obtained. Moreover, the multiple transducers 931s can also obtain moving images by obtaining the still images in multiple frames in the B mode.
The transducer unit 20 for excitation includes at least one first transducer functioning as a transducer for excitation executing excitation by the acoustic radiation pressure in the elastography mode. In the example illustrated in
The large-diameter transducer 21 transmits the ultrasonic waves for excitation with relatively large energy generating the acoustic radiation pressure. The large-diameter transducer 21 has a certain degree of width in the first direction so that the ultrasonic waves for excitation transmitted from the large-diameter transducer 21 become a planar wave Fp (illustrated in
The transducer unit 30 for detection includes multiple second transducers functioning as transducer for detection for detecting a shear wave generated by excitation in the elastography mode. In the example illustrated in
Moreover, the multiple second transducers 31s are also used in the B mode and the like other than the elastography mode. In the B mode, by sequentially switching the position of the ultrasonic beam (scanning line) for the B mode to the first direction, a still image can be obtained. Moreover, the multiple second transducers 31s can also obtain moving images by obtaining the still images in multiple frames in the B mode.
Returning to the description of
The processing circuitry 51 includes a CPU (central processing unit) and a memory. The processing circuitry 51 integrally controls each unit of the main body 12. The processing circuitry 51 receives an output of the transmitter/receiver 55 and can generate information indicating hardness of a tissue such as an organ in a living body and the like by controlling the waveform analyzer 56 conducting the waveform analysis and the hardness estimator 57.
The processing circuitry 51 means a processing circuitry such as an application specific integrated circuit (ASIC) and a programmable logic device in addition to an exclusive or general-purpose CPU (central processing unit) or an MPU (micro processor unit). As the programmable logic device, circuits such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA) can be cited. The processing circuitry 51 reads out and executes programs stored in the storage circuitry 52 or directly incorporated in the processing circuitry 51.
Moreover, the processing circuitry 51 may be constituted by a single circuit or may be constituted by a combination of multiple independent circuits. In the latter case, multiple storage circuitries 52 storing the program may be provided individually for the respective circuits or one storage circuitry 52 may store the program corresponding to functions of the multiple circuits.
The storage circuitry 52 is a magnetic disk (hard disk and the like), an optical disk (CD-ROM, DVD and the like), a recording medium such as a semiconductor memory, and a device for reading out information stored in these mediums. In the storage circuitry 52, control programs for executing transmission/reception conditions, predetermined scanning sequences, image generation, and display processing, various signal data and image data and other data are stored. The data in the storage circuitry 52 can be transferred to an external device (not illustrated).
The input circuitry 53 is a circuit for inputting signals from various switches, buttons, a trackball, a mouse, a keyboard and the like for taking in various instructions from an operator, conditions, setting instructions of regions of interest (ROI), various image quality condition setting instructions and the like into the main body 12. Here, an input device itself is assumed to be included in the input circuitry 53. When the input device is operated by the operator, the input circuitry 53 generates an input signal according to the operation and outputs it to the processing circuitry 51. The main body 12 may include a touch panel in which the input device is constituted integrally with the display 54.
The display 54 displays an elastography image generated by the hardness estimator 57 in accordance with a control signal from the processing circuitry 51. The display 54 is a display device such as a liquid crystal display panel, a plasma display panel, an organic EL panel and the like.
The transmitter/receiver 55 controls transmission of the ultrasonic waves for excitation in the ultrasonic probe 11. The transmitter/receiver 55 includes an excitation waveform generator 551, an excitation transmitter 552, and a frequency setter 553. The excitation transmitter 552 transmits a wave transmission signal based on the waveform generated by the excitation waveform generator 551 to the transducer unit 20 for excitation under control of the processing circuitry 51.
The wave transmission signal from the excitation transmitter 552 is converted to an ultrasonic signal in the large-diameter transducer 21 (illustrated in
Moreover, the transmitter/receiver 55 controls transmission/reception of the ultrasonic waves for detection in the ultrasonic probe 11. The transmitter/receiver 55 includes a detection waveform generator 554, a detection transmitter 555, a detection beam calculator 556, and a wave detector 557. The detection transmitter 555 transmits the ultrasonic waves for excitation under control of the processing circuitry 51 and then, transmits a wave transmission signal electronically focused (transmission delay time and/or reception delay time) in the first direction to the transducer unit 30 for detection so that detection beams Ft1 and Ft2 (illustrated in
The wave transmission signal from the detection transmitter 555 is converted to the ultrasonic signal in the multiple second transducers 31s (illustrated in
Moreover, the multiple second transducers 31s of the transducer unit 30 for detection receive an echo signal caused by a shear wave W (illustrated in
The waveform analyzer 56 makes analysis relating to the shear wave based on the signal input from the wave detector 557 of the transmitter/receiver 55. An analysis relating to the shear wave includes, for example, detection of a peak from a time waveform of the shear wave (corresponding to a graph illustrated in
The hardness estimator 57 calculates a sound speed of the shear wave at each detection position based on the signal input from the waveform analyzer 56 and calculates an average sound speed of the shear wave on the basis of the sound speeds at the multiple detection positions. The hardness estimator 57 estimates a relative value to the average sound speed of each sound speed as hardness (modulus of elasticity) of the tissue. The hardness estimator 57 converts a signal indicating hardness of the tissue to an image signal and has a numeral value indicating the hardness of the tissue and an elastography image indicating distribution of attribution information of a color according to a degree of the numeral value indicating the hardness of the tissue (including information of at least any one of hue information, brightness information, and chroma information) displayed on the display 54.
Moreover, the hardness estimator 57 can also superpose the elastography image on a B-mode image by the B mode executed alternately with the elastography mode and display it on the display 54. Moreover, the hardness estimator 57 can also display multiple frames of elastography images on the display 54.
Subsequently, a difference between a calculation method of a sound speed of the shear wave using the prior-art ultrasonic probe 911 (illustrated in
By using
First, the multiple transducers 931s of the transducer unit 930 both for excitation and detection transmit an ultrasonic pulse (excitation pulse) for excitation electronically focused in the first direction so as to be focused to an excitation position G1. The excitation pulse is focused to the excitation position G1 by the acoustic lens 933 focusing in the second direction. As a result, the transducer unit 930 both for excitation and detection forms an ultrasonic beam (excitation beam) Bp1 for excitation with respect to the excitation position G1. Moreover, since a series of the excitation pulses are repeatedly transmitted from the multiple transducers 931s, the transducer unit 930 both for excitation and detection repeatedly forms the excitation beam Bp1 with respect to the excitation position G1.
When the excitation beam Bp1 is repeatedly formed with respect to the excitation position G1, a shear wave is generated by displacement of the tissue present at the excitation position G1. Here, the shear wave originated in the excitation beam Bp1 and propagating in the first direction is referred to as V1.
Subsequently, after repeated formation of the excitation beam Bp1 with respect to the excitation position G1, the multiple transducers 931s of the transducer unit 930 both for excitation and detection transmits/receives the ultrasonic pulse (detection pulse) for detection electronically focused in the first direction so as to be focused to a detection position H1 set in advance (around the excitation position G1 in the first direction). The detection pulse is focused by the acoustic lens 933 focusing in the second direction to the detection position H1. As a result, the transducer unit 930 both for excitation and detection forms the ultrasonic beam (detection beam) Bt1 for detection with respect to the detection position H1. Moreover, since a series of the detection pulses are repeatedly transmitted/received to/from the multiple transducers 931s, the transducer unit 930 both for excitation and detection repeatedly forms the detection beam Bt1 with respect to the detection position H1.
When the detection beam Bt1 is repeatedly formed at the detection position H1, the shear wave V1 propagating in the first direction is detected. The electronic focusing in the first direction in order to form the detection beam Bt1 is based on the transmission delay time and/or the reception delay time.
Subsequently, after repeated formation of the detection beam Bt1 with respect to the detection position H1, the transducer unit 930 both for excitation and detection repeatedly forms an excitation beam Bp2 with respect to the excitation position G2. When the excitation beam Bp2 is repeatedly formed with respect to the excitation position G2, a shear wave is generated by displacement of the tissue present at the excitation position G2. Here, the shear wave originated in the excitation beam Bp2 and propagating in the first direction is referred to as V2.
Subsequently, after repeated formation of the excitation beam Bp2 to the excitation position G2, the transducer unit 930 both for excitation and detection repeatedly forms a detection beam Bt2 at the detection position H2. When the detection beam Bt2 is repeatedly formed to the detection position H2, the shear wave V2 propagating in the first direction is detected. The electronic focusing in the first direction for forming the detection beam Bt2 is based on the transmission delay time and/or the reception delay time.
When the wave crest of the sear wave V1 generated by the excitation beam Bp1 at the detection position H1 is detected, and the traveling time of the shear wave V1 is measured, the sound speed of the shear wave V1 at the detection position H1 is calculated from “t/d” by the tissue Doppler method or the like. Here, the term “t” is traveling time (time difference) between the transmission time of the excitation beam Bp1 to the arrival time of the wave crest of the shear wave V1 at the detection position H1. Moreover, the term “d” is a distance between the excitation position G1 to the detection position H1. One example of the time waveform of the shear wave at the detection position H1 is illustrated in
As described above, in the prior-art ultrasonic probe 911, the wave crests of the shear waves V1 and V2 propagating in the first direction are detected, respectively, at the two detection positions H1 and H2 along the first direction. Thus, when the traveling time of the wave crests of the shear waves at the two detection positions H1 and H2 along the first direction is to be measured, respectively, by using the prior-art ultrasonic probe 911, time for performing two sessions of a transmission sequence combining transmission of a series of excitation pulses (repeated transmission) and transmission of a series of detection pulses (repeated transmission) is required.
Then, when the traveling time of the wave crests of the shear waves at the three or more detection positions H1, H2, . . . along the first direction is to be measured, respectively, time for performing the transmission sequence in the number of sessions equal to the number of detection positions is required.
As materials for the acoustic lenses 23 and 33, a resin having acoustic impedance close to that of the head portion 40 and a different sound speed or silicon rubber, for example is selected in general. However, the acoustic lenses 23 and 33 may be formed by a rubber member having a shape brought into close contact with a recess portion formed in an inner surface of the head portion 40 or may be formed of an adhesive for bonding the transducer units 20 and 30 to the head portion 40.
The head portion 40 has a shape matching the shapes of the transducer units 20 and 30 in order to fix the transducer units 20 and 30 to the main body of the first ultrasonic probe 11A. The head portion 40 has a structure as illustrated in
By using
First, the large-diameter transducer 21 of the transducer unit 20 for excitation transmits an excitation pulse. The excitation pulse is focused by the acoustic lens 23 focusing in the second direction to an excitation region I (collection of multiple excitation positions extending in the first direction). As a result, the transducer unit 20 for excitation forms an ultrasonic plane (excitation plane) Fp for excitation to the excitation region I. Moreover, since a series of excitation pulses are repeatedly transmitted from the large-diameter transducer 21, the transducer unit 20 for excitation repeatedly forms the excitation plane Fp to the excitation region I.
When the excitation plane Fp is repeatedly formed to the excitation region I, displacement of the tissue present in the excitation region I generates a shear wave. There, the shear wave originated in the excitation plate Fp and propagating in the second direction is referred to as W.
The excitation plane Fp formed by the transducer unit 20 for excitation is focused by the acoustic lens 23 in the second direction but since it has no focusing effect in the first direction, a substantially planar-state wave surface is maintained. The linear excitation region I extending in the first direction at a certain depth is formed, and the shear wave W generated by displacement of the tissue present in the excitation region I propagates in the second direction.
Subsequently, after the repeated formation of the excitation plane Fp to the excitation region I, the multiple second transducers 31s of the transducer unit 30 for detection transmits/receives detection pulses electronically focused in the first direction so as to be focused to the detection position J1 (periphery of the excitation region I in the second direction). The detection pulse is focused to the detection position J1 by the acoustic lens 33 focusing in the second direction. As a result, the transducer unit 30 for detection forms the detection beam Ft1 to the detection position J1. Moreover, since a series of the detection pulses are repeatedly transmitted/received from the multiple second transducers 31s, the transducer unit 30 for detection repeatedly forms the detection beam Ft1 to the detection position J1.
When the detection beam Ft1 is repeatedly formed to the detection position J1, the shear wave W propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft1 is based on the transmission delay time and/or the reception delay time.
Moreover, after the repeated formation of the excitation plane Fp to the excitation region I, the transducer unit 30 for detection repeatedly forms the detection beam Ft2 to the detection position J2 in parallel with (at a same time as) the repeated formation of the detection beam Ft1 to the detection position J1. When the detection beam Ft2 is repeatedly formed to the detection position J2, the shear wave W propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft2 is based on the transmission delay time and/or the reception delay time.
When the wave crest of the shear wave W generated by the excitation plane Fp at the detection position J1 is detected and the traveling time of the shear wave W is measured, the sound speed of the shear wave W at the detection position J1 is calculated by the tissue Doppler method or the like. Moreover, in parallel with calculation of the sound speed of the shear wave W at the detection position J1, the sound speed of the shear wave W generated by the excitation plane Fp at the detection position J2 is also calculated similarly. Moreover, the average sound speed at the two detection positions J1 and J2 is calculated.
As described above, in the first ultrasonic probe 11A, the wave crests of the shear waves W propagating in the orthogonal second direction are detected at the two detection positions J1 and J2 along the first direction, respectively. Thus, when the traveling time of the wave crests of the shear waves W at the two detection positions J1 and J2 along the first direction is to be measured, respectively, by using the first ultrasonic probe 11A, transmission of the series of excitation pulses needs to be performed only one session, and detection operations at the two detection positions J1 and J2 are performed in parallel. Therefore, in the first ultrasonic probe 11A, even when the traveling time of the wave crests of the shear wave W is measured at the two detection positions J1 and J2, respectively, time only for performing one session of the transmission sequence is sufficient.
Then, in the first ultrasonic probe 11A, even when the traveling time of the wave crests of the shear waves is measured, respectively, at three or more detection positions J1, J2, . . . along the first direction, time only for performing one session of the transmission sequence is sufficient. Thus, according to the first ultrasonic probe 11A, the frame rate of the elastography image and the frame rate of the B-mode image by the B-mode performed alternately with the elastography mode are improved.
Moreover, as illustrated in
Here, the B-mode image is generated based on the ultrasonic waves for the B-mode transmitted from the multiple second transducers 31s of the transducer unit 30 for detection before or after a set of formation of the excitation plane Fp and formation of the detection beams Ft1 and Ft2.
Moreover, according to the prior-art ultrasonic probe 911 illustrated in
In the ultrasonic probe 11, a case in which the transducer unit 30 for detection has a 1D structure provided with the multiple second transducers 31s along the first direction will be described as an example. However, the transducer unit 30 for detection may have a 2D structure provided with multiple transducers along the first direction and the second direction. In that case, the acoustic lens 33 is not needed for the transducer unit 30 for detection, and electronic focusing is performed not only in the first direction but also in the second direction.
As illustrated in
Since a structure and a function of the transducer unit 30 for detection illustrated in
By using
First, one transducer of the multiple large-diameter transducers 21s of the transducer unit 20 for excitation transmits excitation pulses. The excitation pulses are focused by the acoustic lens 23 focusing in the second direction to an excitation region I1. As a result, the transducer unit 20 for excitation forms the excitation plane Fp1 to the excitation region I1. Moreover, since a series of the excitation pulses are repeatedly transmitted from the transducer, the transducer unit 20 for excitation repeatedly forms the excitation plane Fp1 to the excitation region I1.
When the excitation plane Fp1 is repeatedly formed to the excitation region I1, a shear wave is generated by displacement of a tissue present in the excitation region I1. Here, a shear wave originated in the excitation plane Fp1 and propagating in the second direction is referred to as W1.
Moreover, in parallel with (at a same time as) repeated formation of the excitation plane Fp1 to the excitation region I1, the transducer unit 20 for excitation repeatedly forms the excitation plane Fp2 to an excitation region 12.
When the excitation plane Fp2 is repeatedly formed to the excitation region 12, the shear wave is generated by displacement of the tissue present in the excitation region 12. Here, the shear wave originated in the excitation plane Fp2 and propagating in the second direction is referred to as W2.
The excitation planes Fp1 and Fp2 formed by the transducer unit 20 for excitation are focused by the acoustic lens 23 in the second direction but since it has no focusing effect in the first direction, a substantially planar-state wave surface is maintained. The linear excitation regions I1 and I2 extending in the first direction at a certain depth are formed, and the shear waves W1 and W2 generated by displacement of the tissue present in the excitation regions I1 and 12 propagate in the second direction.
Subsequently, after the formation of the excitation plane Fp1 to the excitation region I1, the multiple second transducers 31s of the transducer unit 30 for detection transmits/receives detection pulses electronically focused in the first direction so as to be focused to the detection position J1 (periphery of the excitation region I1 in the second direction). The detection pulse is focused to the detection position J1 by the acoustic lens 33 focusing in the second direction. As a result, the transducer unit 30 for detection forms the detection beam Ft1 to the detection position J1. Moreover, since a series of the detection pulses are repeatedly transmitted/received from the multiple second transducers 31s, the transducer unit 30 for detection repeatedly forms the detection beam Ft1 to the detection position J1.
When the detection beam Ft1 is repeatedly formed to the detection position J1, the shear wave W1 propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft1 is based on the transmission delay time and/or the reception delay time.
Moreover, after the repeated formation of the excitation plane Fp2 to the excitation region 12, the transducer unit 30 for detection repeatedly forms the detection beam Ft2 to the detection position J2 in parallel with (at a same time as) the repeated formation of the detection beam Ft1 to the detection position J1. When the detection beam Ft2 is repeatedly formed to the detection position J2, the shear wave W2 propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft2 is based on the transmission delay time and/or the reception delay time.
When the wave crest of the shear wave W1 generated by the excitation plane Fp1 at the detection position J1 is detected and the traveling time of the shear wave W1 is measured, the sound speed of the shear wave W1 at the detection position J1 is calculated by the tissue Doppler method or the like. Moreover, in parallel with calculation of the sound speed of the shear wave W1 at the detection position J1, the sound speed of the shear wave W2 generated by the excitation plane Fp2 at the detection position J2 is also calculated similarly. Moreover, the average sound speed at the two detection positions J1 and J2 is calculated.
As described above, in the second ultrasonic probe 11B, the wave crests of the shear waves W1 and W2 propagating in the orthogonal second direction are detected, respectively, at the two detection positions J1 and J2 along the first direction. Thus, when the traveling time of the wave crests of the shear waves W1 and W2 at the two detection positions J1 and J2 along the first direction is to be measured, respectively, by using the second ultrasonic probe 11B, excitation operations for the two excitation regions I1 and 12 are performed in parallel, and detection operations at the two detection positions J1 and J2 are performed in parallel. Therefore, in the second ultrasonic probe 11B, even when the traveling time of the wave crests of the shear waves W1 and W2 are measured at the two detection positions J1 and J2, respectively, time only for per only one session of the transmission sequence is sufficient.
Then, in the second ultrasonic probe 11B, even when the traveling time of the wave crests of the shear waves is measured, respectively, at three or more detection positions J1, J2, . . . along the first direction, time only for performing one session of the transmission sequence is sufficient. Thus, according to the second ultrasonic probe 11B, the frame rate of the elastography image and the frame rate of the B-mode image by the B-mode performed alternately with the elastography mode are improved.
Moreover, when the second ultrasonic probe 11B is used, the interval D between the excitation region I1 and the detection position J1 and the interval D between the excitation region 12 and the detection position J2 have a certain value. Thus, when the second ultrasonic probe 11B is used, the uniformity of the image quality of the entire elastography image is improved.
Moreover, according to the second ultrasonic probe 11B, the transducer unit 20 for excitation for transmitting the excitation pulse independently from the transducer unit 30 for detection is provided. Thus, as the multiple large-diameter transducer 21s provided in the transducer unit 20 for excitation, the one with an optimal frequency characteristic for effectively generating an acoustic radiation pressure and the one capable of outputting optimal acoustic sound can be selected.
In addition, in the case of the second ultrasonic probe 11B, since a required region is selected from the multiple regions along the first direction, it becomes possible to form the excitation plane Fp1 (Fp2) in a limited range along the first direction instead of the entire range along the first direction, and wasteful energy consumption for transmission of the excitation pulse can be reduced. In that case, the processing circuitry 51 (illustrated in
As illustrated in
Since a structure and a function of the transducer unit 30 for detection illustrated in
By using
First, the large-diameter transducer 211 of the transducer unit 201 for excitation transmits excitation pulses. The excitation pulses are focused by the acoustic lens 231 focusing in the second direction to the excitation region I1. As a result, the transducer unit 201 for excitation forms the excitation plane Fp1 to the excitation region I1. Moreover, since a series of the excitation pulses are repeatedly transmitted from the large-diameter transducer 211, the transducer unit 201 for excitation repeatedly forms the excitation plane Fp1 to the excitation region I1.
When the excitation plane Fp1 is repeatedly formed to the excitation region I1, a shear wave is generated by displacement of a tissue present in the excitation region I1. Here, a shear wave originated in the excitation plane Fp1 and propagating in the second direction is referred to as W1.
Moreover, in parallel with (at a same time as) repeated formation of the excitation plane Fp1 to the excitation region I1, the transducer unit 202 for excitation repeatedly forms the excitation plane Fp2 to an excitation region 12. When the excitation plane Fp2 is repeatedly formed to the excitation region 12, the shear wave is generated by displacement of the tissue present in the excitation region 12. Here, the shear wave originated in the excitation plane Fp2 and propagating in the second direction is referred to as W2.
The excitation planes Fp1 and Fp2 formed by the transducer units 201 and 202 for excitation are focused by the acoustic lenses 231 and 232 in the second direction but since it has no focusing effect in the first direction, a substantially planar-state wave surface is maintained. The linear excitation regions I1 and 12 extending in the first direction at a certain depth are formed, and the shear waves W1 and W2 generated by displacement of the tissue present in the excitation regions I1 and 12 propagate in the second direction.
The positions of the excitation regions I1 and 12 in a depth direction are equal but in
Subsequently, after the repeated formation of the excitation planes Fp1 and Fp2 to the excitation regions I1 and I2, the multiple second transducers 31s of the transducer unit 30 for detection transmits/receives detection pulses electronically focused in the first direction so as to be focused to the detection position J1 (peripheries of the excitation regions I1 and 12 in the second direction). The detection pulse is focused to the detection position J1 by the acoustic lens 33 focusing in the second direction. As a result, the transducer unit 30 for detection forms the detection beam Ft1 to the detection position J1. Moreover, since a series of the detection pulses are repeatedly transmitted/received to/from the multiple second transducers 31s, the transducer unit 30 for detection repeatedly forms the detection beam Ft1 to the detection position J1.
When the detection beam Ft1 is repeatedly formed to the detection position J1, the shear waves W1 and W2 propagating in the second direction are detected. The electronic focusing in the first direction for forming the detection beam Ft1 is based on the transmission delay time and/or the reception delay time.
Moreover, after the repeated formation of the excitation planes Fp1 and Fp2 to the excitation regions I1 and 12, the transducer unit 30 for detection repeatedly forms the detection beam Ft2 to the detection position J2 in parallel with (at a same time as) the repeated formation of the detection beam Ft1 to the detection position J1. When the detection beam Ft2 is repeatedly formed to the detection position J2, the shear waves W1 and W2 propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft2 is based on the transmission delay time and/or the reception delay time.
When the wave crests of the shear waves W1 and W2 generated by the excitation planes Fp1 and Fp2 at the detection position J1 is detected, respectively, and the traveling time (average value) of the shear waves W1 and W2 is measured, the sound speed (average value) of the shear waves W1 and W2 at the detection position J1 is calculated by the tissue Doppler method or the like. Moreover, in parallel with calculation of the sound speeds of the shear waves W1 and W2 at the detection position J1, the sound speed of the shear waves W1 and W2 generated by the excitation planes Fp1 and Fp2 at the detection position J2 is also calculated similarly. Moreover, the average sound speed at the two detection positions J1 and J2 is calculated.
As described above, in the third ultrasonic probe 11C, the wave crests of the shear waves W1 and W2 propagating in the orthogonal second direction are detected at the two detection positions J1 and J2 along the first direction. Thus, when the traveling time of the wave crests of the shear waves W1 and W2 at each of the two detection positions J1 and J2 along the first direction is to be measured, respectively, by using the third ultrasonic probe 11C, excitation operations for the two excitation regions I1 and 12 are performed in parallel, and detection operations at the two detection positions J1 and J2 are performed in parallel. Therefore, in the third ultrasonic probe 11C, even when the traveling time of the wave crests of the shear waves W1 and W2 is measured at the two detection positions J1 and J2, respectively, time only for performing one session of the transmission sequence is sufficient.
Then, in the third ultrasonic probe 11C, even when the traveling time of the wave crests of the shear waves is measured, respectively, at three or more detection positions J1, J2, . . . along the first direction, time only for performing one session of the transmission sequence is sufficient. Thus, according to the third ultrasonic probe 11C, the frame rate of the elastography image and the frame rate of the B-mode image by the B-mode performed alternately with the elastography mode are improved.
Moreover, when the third ultrasonic probe 11C is used, the interval D between the excitation region I1 and the detection position J1, the interval D between the excitation region I1 and the detection position J2, the interval D between the excitation region 12 and the detection position J1, and the interval D between the excitation region 12 and the detection position J2 have a certain value. Thus, when the third ultrasonic probe 11C is used, the uniformity of the image quality of the elastography image is improved.
Moreover, according to the third ultrasonic probe 11C, the transducer units 201 and 202 for excitation for transmitting the excitation pulse independently from the transducer unit 30 for detection is provided. Thus, as the large-diameter transducers 211 and 212 provided in the transducer units 201 and 202 for excitation, the one with an optimal frequency characteristic for effectively generating an acoustic radiation pressure can be selected.
In addition, if the elastography image is displayed by being superposed on an ordinary B-mode image obtained by using the transducer unit 30 for detection, a section of the B-mode image and a section of the elastography image are slightly different in the first ultrasonic probe 11A (illustrated in
A structure of the second ultrasonic probe 11B may be combined with the third ultrasonic probe 11C. That is, each of the transducer units 201 and 202 for excitation of the third ultrasonic probe 11C may include one large-diameter transducer in each region of the multiple regions divided along the first direction (multiple large-diameter transducers corresponding to multiple regions, respectively).
As illustrated in
Since a structure and a function of the transducer unit 30 for detection illustrated in
By using
First, the multiple first transducers 21s of the transducer unit 20 for excitation transmit the excitation plane Fp electronically focused in the second direction so as to be focused to the excitation region I. As a result, the transducer unit 20 for excitation forms the excitation plane Fp to the excitation region I. Moreover, since a series of the excitation pulses are repeatedly transmitted from the multiple first transducers 21s, the transducer unit 20 for excitation repeatedly forms the excitation plane Fp to the excitation region I.
When the excitation plane Fp is repeatedly formed to the excitation region I, a shear wave is generated by displacement of a tissue present in the excitation region I. Here, a shear wave originated in the excitation plane Fp and propagating in the second direction is referred to as W.
The excitation plane Fp formed by the transducer unit 20 for excitation is electronically focused in the second direction but since it has no focusing effect in the first direction, a substantially planar-state wave surface is maintained. The linear excitation region I extending in the first direction at a certain depth is formed, and the shear wave W generated by displacement of the tissue present in the excitation region I propagates in the second direction.
Subsequently, after the repeated formation of the excitation plane Fp to the excitation region I, the multiple second transducers 31s of the transducer unit 30 for detection transmits/receives detection pulses electronically focused in the first direction so as to be focused to the detection position J1 (periphery of the excitation region I in the second direction). The detection pulse is focused to the detection position J1 by the acoustic lens 33 focusing in the second direction. As a result, the transducer unit 30 for detection forms the detection beam Ft1 to the detection position J1. Moreover, since a series of the detection pulses are repeatedly transmitted/received to/from the multiple second transducers 31s, the transducer unit 30 for detection repeatedly forms the detection beam Ft1 to the detection position J1.
When the detection beam Ft1 is repeatedly formed to the detection position J1, the shear wave W propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft1 is based on the transmission delay time and/or the reception delay time.
Moreover, after the repeated formation of the excitation plane Fp to the excitation region I, the transducer unit 30 for detection repeatedly forms the detection beam Ft2 to the detection position J2 in parallel with (at a same time as) the repeated formation of the detection beam Ft1 to the detection position J1. When the detection beam Ft2 is repeatedly formed to the detection position J2, the shear wave W propagating in the second direction is detected. The electronic focusing in the first direction for forming the detection beam Ft2 is based on the transmission delay time and/or the reception delay time.
When the wave crest of the shear wave W generated by the excitation plane Fp at the detection position J1 is detected and the traveling time of the shear wave W is measured, the sound speed of the shear wave W at the detection position J1 is calculated by the tissue Doppler method or the like. Moreover, in parallel with calculation of the sound speed of the shear wave W at the detection position J1, the sound speed of the shear wave W generated by the excitation plane Fp at the detection position J2 is also calculated similarly. Moreover, the average sound speed at the two detection positions J1 and J2 is calculated.
As described above, in the fourth ultrasonic probe 11D, the wave crests of the shear waves W propagating in the orthogonal second direction are detected at the two detection positions J1 and J2 along the first direction, respectively. Thus, when the traveling time of the wave crests of the shear waves W at the two detection positions J1 and J2 along the first direction is measured, respectively, by using the fourth ultrasonic probe 11D, transmission of the series of excitation pulses needs to be performed only one session, and detection operations at the two detection positions J1 and J2 are performed in parallel. Therefore, in the fourth ultrasonic probe 11D, even when the traveling time of the wave crests of the shear wave W is measured at the two detection positions J1 and J2, respectively, time only for performing one session of the transmission sequence is sufficient.
Then, in the fourth ultrasonic probe 11D, even when the traveling time of the wave crests of the shear waves is measured, respectively, at three or more detection positions J1, J2, . . . along the first direction, time only for performing one session of the transmission sequence is sufficient. Thus, according to the fourth ultrasonic probe 11D, the frame rate of the elastography image and the frame rate of the B-mode image by the B-mode performed alternately with the elastography mode are improved.
Moreover, when the fourth ultrasonic probe 11D is used, the interval D between the excitation region I and the multiple detection positions J1 and J2 has a certain value. Thus, when the fourth ultrasonic probe 11D is used, the uniformity of the image quality of the elastography image is improved.
Moreover, according to the fourth ultrasonic probe 11D, the transducer unit 20 for excitation for transmitting the excitation pulse independently from the transducer unit 30 for detection is provided. Thus, as the multiple first transducer 21s provided in the transducer unit 20 for excitation, the one with an optimal frequency characteristic for effectively generating an acoustic radiation pressure and the one capable of outputting optimal acoustic sound can be selected.
In addition, when the fourth ultrasonic probe 11D is used, electronic focusing is performed in the second direction so that the excitation plane Fp is focused to the desired excitation region I (transmission delay time is given). When the fourth ultrasonic probe 11D is used, the excitation plane Fp can be formed with a larger diameter as compared with use of the first ultrasonic probe 11A (illustrated in
As illustrated in
In the case of the fifth ultrasonic probe 11E, as described by using the second ultrasonic probe 11B in
Moreover, in the case of the fifth ultrasonic probe 11E, the effect similar to the case of the fourth ultrasonic probe 11D illustrated in
As illustrated in
Since a structure and a function of the transducer unit 30 for detection illustrated in
By transmitting the ultrasonic waves for excitation from all the multiple first transducers 21s, the planar wave Fp is formed similarly to the case of the first ultrasonic probe 11A illustrated in
In the case of the sixth ultrasonic probe 11F, the excitation plane can be formed in a limited range along the first direction, and wasteful energy consumption for transmission of the excitation pulse can be reduced. In that case, the transducer unit 20 for excitation transmits the excitation pulse from a part of the multiple first transducers 21s under control of the processing circuitry 51.
Moreover, in the case of the sixth ultrasonic probe 11F, the effect similar to the case of the first ultrasonic probe 11A illustrated in
The seventh ultrasonic probe 11G includes an insertion portion 111 which can be inserted into an object. The insertion portion 111 includes one transducer unit 20 for excitation along the second direction and one transducer unit 30 for detection. The transducer unit 30 for detection is provided on one side along the second direction of the transducer unit 20 for excitation. The second direction follows an axis R of the sixth ultrasonic probe 11F.
As illustrated in
Each of the multiple first transducers 21s transmits ultrasonic waves for excitation with relatively large energy generating an acoustic radiation pressure. The transducer unit 20 for excitation includes an acoustic matching layer, a backing, an acoustic lens and the like but they are not illustrated in
On the other hand, the transducer unit 30 for detection includes multiple second transducers 31s along the third direction. The multiple second transducers 31s are convex arrays. An example in which the transducer unit 30 for detection is provided on a tip end side rather than the transducer unit 20 for excitation is illustrated but this is not limiting.
Each of the multiple second transducers 31s transmits/receives the ultrasonic waves for detection with relatively smaller energy than the ultrasonic waves for excitation. The transducer unit 30 for detection includes an acoustic matching layer, a backing, an acoustic lens and the like but they are not illustrated in
Moreover, the multiple second transducers 31s are also used in the B mode and the like other than in the elastography mode. In the B mode, a still image can be obtained by sequentially switching a position of an ultrasonic beam (scanning line) for the B mode to the third direction. Moreover, the multiple second transducers 31s can obtain moving images by obtaining still images in multiple frames in the B mode.
By transmitting the ultrasonic waves for excitation from all of the multiple first transducers 21s, the planar wave Fp is formed similarly to the case of the first ultrasonic probe 11A illustrated in
In the case of the seventh ultrasonic probe 11G, an excitation plane can be formed in a limited range along the first direction, and wasteful energy consumption for transmission of the excitation pulse can be reduced. In that case, the transducer unit 20 for excitation transmits the excitation pulse from a part of the multiple first transducers 21s under control of the processing circuitry 51.
Moreover, in the case of the seventh ultrasonic probe 11G, the effect similar to the case of the first ultrasonic probe 11A illustrated in
According to the ultrasonic probe of at least one of the aforementioned embodiments, information to generate an elastography image can be generated in time required for the minimum number of times of transmission sequences. According to the ultrasonic diagnosis apparatus of at least one of the aforementioned embodiments, an elastography image can be generated in time required for the minimum number of times of transmission sequences, and the elastography image with a high frame rate can be obtained while uniformity of the image quality of the entire elastography image is improved.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-238641 | Nov 2014 | JP | national |
| 2015-226812 | Nov 2015 | JP | national |
