This application claims the benefit of Taiwan Patent Application Serial No. 104114713, filed May 8, 2015, the subject matter of which is incorporated herein by reference.
1. Field of the Invention
The present invention is related to a system for generating elasticity image, and more particularly related to a system for generating elasticity image, which generates the elasticity image by transmitting ultrasound waves and receiving displacement signals at different locations of the organic medium.
2. Description of the Prior Art
Ultrasound imaging has been widely applied to medical diagnosis. Compared to other clinical medical imaging modalities such as X-ray, CT, MRI and nuclear imaging systems, ultrasound imaging is characterized as cost effective, free of ionizing radiation, non-invasive and real-time. It can also be portable, with sub-millimeter spatial resolution, and can be used for blood flow detection. Hence, ultrasound imaging has been widely utilized to assist clinical diagnosis.
Ultrasound imaging is based on reflection and backscattering of high frequency sound waves. Specifically, a probe is required for radiating a sound wave into a human body. The interaction between sound wave and the tissues inside the human body produces echoes that are detected by the probe and images are reconstructed by the system based on the received echoes.
However, conventional ultrasound imaging often has limited tissue contrast, thus making early detection of diseases difficult. In order to enhance early detection of diseases, elasticity imaging has emerged. One method for elasticity imaging is based on analysis of tissue movement before and after compression by an external device. Echo signals are used to estimate the displacement along the compression direction to compute spatial derivative of displacement. With such methods, the stiffness information (e.g. deformation and elasticity) of the medium can be available to enhance diagnosis accuracy.
Despite the widespread use of the compression based elasticity imaging methods, they cannot provide quantitative elasticity information. It is clear that an improvement is highly desirable.
For the existing elasticity imaging methods, it is a general problem that quantitative stiffness information cannot be accessed. Accordingly, it is a main object of the present invention to provide a system for generating elasticity image which transmits ultrasound waves and receives the displacement signals at different locations of the organic medium to generate the elasticity image so as to resolve the above mentioned problem.
According to the above mentioned object, a system for generating elasticity image is provided in accordance with an object of the present invention for generating a spatial elasticity image of an organic medium. The system for generating elasticity image comprises a transmission-reception system and a processing module. The transmission-reception system comprises a transmission device and a reception device. The transmission device is utilized for transmitting an ultrasound wave to a first transmission location of the organic medium at a first time to generate a shear wave in the organic medium, and the shear wave triggers a first displacement signal to be generated at a first reception location at a second time. The reception device is utilized for receiving the first displacement signal and generating a triggering signal according to the first displacement signal. The processing module is electrically connected to the transmission device and the reception device of the transmission-reception system to receive the triggering signal and calculating a first shear wave travelling time and a first location difference according to the first time, the second time, the first transmission location, and the first reception location so as to compute a first shear wave travelling speed.
Wherein, the transmission-reception system is triggered to transmit the ultrasound wave to a second transmission location of the organic medium at a third time and to receive a second displacement generated at a second reception location of the organic medium at a fourth time, and the processing module computes a second shear wave travelling speed according to a second shear wave travelling time, which is calculated by using the third time and the fourth time, and a second location difference, which is calculated by using the second transmission location and the second reception location, and generates the spatial elasticity image according to the first shear wave travelling speed and the second shear wave travelling speed.
In accordance with a preferred embodiment of the present invention, the system for generating elasticity image further comprises a rotation device, which is elastically connected to the processing module. The transmission-reception system is disposed on the rotation device, and the processing module triggers the rotation device to rotate along a rotation direction through a rotation angle to have the transmission device and the reception device of the transmission-reception system moved to the second transmission location and the second reception location. In addition, the transmission-reception system is an one-dimensional-array probe, and the transmission device and the reception device are an ultrasound transmission probe and an ultrasound reception probe of the one-dimensional-array probe respectively. Moreover, the processing module triggers the rotation device to rotate along the rotation direction through the rotation angle N times repeatedly to generate the spatial elasticity image according to a number of N of the first shear wave travelling speeds and a number of N of the second shear wave travelling speeds, the first location difference is smaller than a wavelength of the shear wave, and the second location difference is smaller than the wavelength of the shear wave.
In accordance with a preferred embodiment of the system for generating elasticity image, the transmission-reception system is a two-dimensional-array probe, and the transmission-reception system is triggered by the processing module to transmit the ultrasound wave at the second transmission location and receive the second displacement signal at the second reception location by using different probes. In addition, the two-dimensional-array probe is a cross-shaped array probe, the first location difference is smaller than a wavelength of the shear wave, and the second location difference is smaller than the wavelength of the shear wave.
In accordance with a preferred embodiment of the system for generating elasticity image, the transmission device and the reception device are both a two-dimensional-array probe, and the transmission device is triggered by the processing module to transmit the ultrasound wave at the second transmission location by using another probe which is different from a probe of the transmission device being used for transmitting the ultrasound wave at the first transmission location, and reception device is triggered by the processing module to receive the second displacement signal at the second reception location by using another probe which is different from a probe of the reception device being used for receiving the first displacement signal, the first location difference is smaller than a wavelength of the shear wave, and the second location difference is smaller than the wavelength of the shear wave
By using the system for generating elasticity image provided in the present invention, because the system can transmit ultrasound wave and receive the displacement signal at different locations of the organic medium, the hardness condition of the whole interior of the organic medium can be detected such that the definitive diagnosis rate can be enhanced and the problem of the conventional art can be resolved.
The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:
There are various embodiments of the system for generating elasticity image in accordance with the present invention, which are not repeated hereby. Only four preferred embodiments are mentioned in the following paragraph as an example.
Please refer to
As shown, the system 1 for generating elasticity image in accordance with the first preferred embodiment of the prevent invention is utilized for generating a spatial elasticity image of an organic medium 2. The organic medium 2 can be a cell, a tissue, a blood vessel or an organ (such as liver) of an organism. However, the present invention is not so restricted.
The system 1 for generating elasticity image includes a transmission-reception system 11, a processing module 12, and a rotation device 13. The transmission-reception system 11 is disposed adjacent to the organic medium 2 as shown in
The processing module 12 is electrically connected to the transmission device 111 and the reception device 112, such as the above mentioned ultrasound wave system, of the transmission-reception system 11. The processing module 12 can be an ordinary circuitry or chip with processing capability, such as central processing unit (CPU), graphics processing unit (GPU) or accelerated processing unit (APU). The processing module 12 can be integrated inside the reception device 112 or arranged in a separate electronic devices such as a tablet or a desktop computer.
The rotation device 13 is electrically connected to the processing module 12 and includes a rotation allocation device 131 and a rotation main body 132. The rotation main body 132 is rotatably disposed in the rotation allocation device 131 and engaged with the motor inside the rotation allocation device 131. The transmission device 111 and the reception device 112 are disposed on the rotation main body 132 by means of fitting for example. However, the present invention is not so restricted.
When using the system 1 for generating elasticity image provided in accordance with the first embodiment of the present invention, the user may use the processing module 12 to trigger (by pushing a button or other ways) the transmission device 111 of the transmission-reception system 11 to transmit an ultrasound wave W1. In the first preferred embodiment of the present invention, the transmission device 111 is disposed adjacent to the surface of the organic medium 2 and is triggered to transmit the ultrasound wave W1 at a first time. The transmission device 111 transmits the ultrasound wave W1 (transmitted along longitudinal direction) to a first transmission location P1 in the organic medium 2 at the first time to generate a shear wave W2 (transmitted along latitudinal direction) in the organic medium 2. The shear wave W2 triggers a first displacement signal W3 (transmitted along longitudinal direction) to be generated at a first reception location P2 in the organic medium 2 at a second time.
The reception device 112 is disposed adjacent to the transmission device 111, and in fact, the reception device 112 is located on the above mentioned first reception location P2 (i.e. the reception device 112 and the first reception location P2 are located on the same vertical plane). Thus, the reception device 112 receives the first displacement signal W3 at the first reception location P2 at the second time and transmits a trigger signal S1 according to the first displacement signal W3.
It is noted that the transmission device 111 is disposed at the first transmission location P1, the reception device 112 is disposed at the first reception location P2, and there has a first location difference d1 between the first transmission location P1 and the first reception location P2. In addition, the shear wave W2 has a wavelength (not shown) defined as λ. The first location difference d1 should be smaller than the wavelength of the shear wave (d1<λ) in all the preferred embodiments of the present invention. To be more precise, the location difference between the location of the transmission device 111 and the location of the reception device 112 should be smaller than the wavelength of the shear wave, and the location difference is defined as the linear distance. In the preferred embodiment of the present invention, a two-dimensional plane is used for illustration.
After receiving the trigger signal S1, the processing module 12 calculates a first shear wave travelling time and a first location difference according to the first time and the second time, as well as the first transmission location P1 and the first reception location P2 respectively. Concretely speaking, the first shear wave travelling time is the difference between the second time and the first time, the first location difference is the linear distance calculated by subtracting the coordinate of the first transmission location P1 from the coordinate of the first reception location P2. Because the first reception location P2 and the first transmission location P1 are on the same horizontal plane, the calculated location difference would be the horizontal distance. After calculating the first shear wave travelling time and the first location difference d1, the processing module 12 can further compute the first shear wave travelling speed based on the first shear wave travelling time and the first location difference d1 by dividing the first location difference d1 by the first shear wave travelling time for example.
After computing the first shear wave travelling time, the processing module 12 may store the first shear wave travelling time and trigger the motor within the rotation allocation device 131 of the rotation device 13 to rotate such that the rotation main body 132 is driven to rotate along a rotation direction L through a rotation angle so as to have the transmission device 111 and the reception device 112 of the transmission-reception system 11 moved to a second transmission location P3 and a second reception location P4 (in the present embodiment, the transmission-reception system is self-rotated. However, the present invention is not so restricted). In the first preferred embodiment, the rotation direction L is the clockwise direction as shown in
After the transmission device 111 and the reception device 112 are moved by the rotation main body 132 to the second transmission location P3 and the second reception location P4, the processing module 12 triggers the transmission device 111 of the transmission-reception system 11 to transmit an ultrasound wave W4 to the second transmission location P3 of the organic medium 2 at a third time and triggers the reception device 112 to receive a second displacement signal W5 generated at the second reception location P4 of the organic medium 2 at a fourth time such that the processing module 12 can compute a second shear wave travelling speed by using a second shear wave travelling time calculated from the third time and the fourth time and a second location difference calculated from the second transmission location and the second reception location. The generation of the second displacement signal W5 is identical to that of the first displacement signal W3 and the calculation of the second shear wave travelling speed is identical to the calculation of the first shear wave travelling speed, and thus are not repeated here. After the second shear wave travelling speed is computed, the processing module 12 accesses the first shear wave travelling speed to build up the spatial distribution of the shear wave travelling speed inside the organic medium 2 by using the first shear wave travelling speed and the second shear wave travelling speed and further transforming the speed distribution into the spatial distribution of elastic coefficient so as to generate the spatial elasticity image.
It is noted that the above mentioned first transmission location P1, the first reception location P2, the second transmission location P3, and the second reception location P4 indicate the locations inside the organic medium 2 in a narrow sense. However, in a broad meaning, these locations can be the vertical corresponding locations outside the organic medium 2. In addition, the rotation angle is 90 degrees in the first preferred embodiment, however, the present invention is not so restricted. The rotation angle can be 1 degree or other different angles, and the rotation device 13 can be repeatedly triggered to generate the rotation continuously. That is, an integrated circular scan of 360 degrees can be performed to build up a spatial elasticity image of 360 degrees. To perform the above mentioned operation, the processing module may have a build-in rotation procedure, which can be set to control the rotation angle. For example, the setting of the rotation procedure is to trigger the transmission device 111 and the reception device 112 to transmit the ultrasound wave and receive the displacement signal after every rotation though a rotation angle of one degree so as to detect the organic medium 2 along N different angles to generate N sets of data with N first shear wave travelling speeds and N second shear wave travelling speeds to generate the elasticity image, and the rotation procedure would be stopped until the rotation device is back to the original location.
Moreover, in the other embodiments, the process of transmitting the ultrasound wave W1 and receiving the first displacement signal W3 can be repeated at the same location, for example, the processing module 12 may trigger the rotation device 13 to be rotated to the next preset angle after repeatedly receiving the first displacement signal W3 at the frequency of 2000 Hz forty times. In the other embodiments, other than the above mentioned self-rotated circular scan, the transmission-reception system may be disposed on an orbit to move along a square path, a circular path, or other polygonal path to proceed the scan, and it may be set to trigger the transmission of the ultrasound wave after moving with a certain distance, for example, it may be set to execute M times of transmission and reception within a total distance, to generate the elasticity image according to the above mentioned data.
Please refer to
wherein
Δs is the reverse of speed value of each grid, Δt is the time calculated from time-to-flight value of the received shear wave signals (i.e. time difference between the first time and the second time, which is also the first shear wave travelling time). Thus, if K different angles are scanned and the target region is divided into M*N grids, L would be a matrix of K*MN, Δs would be the row-vector of MN*1, and Δt would be the row-vector of K*1.
In the other preferred embodiments, if the scan process is executed every degree, i.e. K is 360, because the transmission device 111 and the reception device 112 are rotated around a fixed center, the travelling path of the shear wave W2 would be the diameter of different angles such that the value can be calculated geometrically, and Δt can be accessed from experimental data. Then, Δs can be calculated from the inverse of matrix to calculate the distribution of shear wave travelling speed within the scanning range so as to generate the diagram of speed distribution (spatial elasticity image) as shown in
In addition, it is noted that the processing module 12d may have a build-in transmission-reception procedure. That is, after the processing module 12d receives the displacement signal from the reception device 112d, the processing module 12d triggers one of the probes of the transmission-reception system 11d as the transmission device 111e to transmit the ultrasound wave according to the transmission-reception procedure, and triggers one of the probes of the transmission-reception system 11d as the reception device 112e to receive the displacement signal so as to compute travelling speed of the shear wave in each space region to generate the spatial elasticity image.
Moreover, it should be noted that the processing module 12f may have a build-in transmission-reception procedure. That is, after each reception of the displacement signal from a probe in the reception device 112f, the processing module 12f triggers another probe in the transmission device 111f to transmit ultrasound wave and triggers another probe in the reception device 112f to receive the displacement signal so as to compute travelling speed of the shear wave in each of the space region to generate the spatial elasticity image.
In conclusion, by using the system for generating elasticity image provided in the present invention, because the system can transmit ultrasound wave and receive the displacement signal at different locations of the organic medium, the hardness condition of the whole interior of the organic medium can be detected such that the definitive diagnosis rate can be enhanced and the problem of the conventional art can be resolved.
The detail description of the aforementioned preferred embodiments is for clarifying the feature and the spirit of the present invention. The present invention should not be limited by any of the exemplary embodiments described herein, but should be defined only in accordance with the following claims and their equivalents. Specifically, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
104114713 | May 2015 | TW | national |