KR101525433B1 - Lesion Monitoring Method and Medical Imaging System - Google Patents

Abstract

A method and a system of monitoring changes in a lesion state by using an ultrasonic echo signal reflected from an object are disclosed. The lesion monitoring method comprises: a first step of establishing ROI data for the lesion from an ultrasonic image reflected from an object; a second step of generating a fundamental image and a harmonic image from an ultrasonic echo signal for the object into which a contrast agent is injected; a third step of generating amended ROI data by tracking the position of the lesion on the basis of the ROI data in the fundamental image; and a fourth step of quantifying the lesion in the harmonic image on the basis of the amended ROI data.

Description

[0001] The present invention relates to a lesion monitoring method and a medical imaging system,

The present invention relates to a medical condition monitoring method and a medical imaging system, and more particularly, to monitoring a medical treatment effect through lesion tracking and quantification thereof in an ultrasound contrast agent image.

An ultrasound imaging system transmits an ultrasound signal to a target object while a probe including a plurality of conversion elements is in contact with the surface of the target object, receives ultrasound echoes reflected from the target object through a probe, And displays the formed ultrasound image through a display to inspect the internal state of the object.

Recently, Contrast-enhanced Ultrasonography (CEUS) imaging system using Ultrasound Contrast Agents (UCAs) has been used in a variety of fields such as the vascular system including the cerebrovascular system and cancer diagnosis such as breast cancer.

The contrast enhancement ultrasound imaging system is a system for diagnosing the location and condition of a lesion using ultrasound contrast agent injected into the blood vessel, focusing on the lesion along the blood flow and using the echoes of the fine bubbles of the contrast agent exposed to the ultrasound.

This contrast enhanced ultrasound imaging system has the merit of observing the lesion in real time compared to the interventional procedure using CT (computerized tomography) or MRI (Magnetic Resonance Imager) and confirming the result in real time. Unlike the contrast media used, ultrasound contrast agents have the advantage of significantly lowering the incidence of side effects and allergic reactions to the human body.

In this regard, Korean Patent Publication No. 2011-0089137 discloses a technique called " Real-time perfusion imaging and quantification ", and discloses a technique in which lesions in a body part use a difference in perfusion kinetics, And distinguishes benign lesions from malignant lesions in accordance with the difference in blood vessel properties.

However, the conventional contrast enhancement ultrasound imaging system does not perform objective diagnosis and treatment effect evaluation because the examiner should visually observe and change the position of the lesion according to the respiration or movement of the examinee and perform qualitative evaluation. Therefore, There is a problem in that the interpretation and the diagnosis are varied.

Korean Patent Publication No. 2011-0089137, "Real-time Perfusion Imaging and Quantification"

Disclosure of Invention Technical Problem [8] The present invention has been made to solve the above-described problems, and it is an object of the present invention to enable the diagnosis of an objective lesion state and evaluation of a therapeutic effect by automatically tracking lesions and quantifying the lesions in an ultrasound image without qualitative evaluation of the user.

According to another aspect of the present invention, there is provided a method for monitoring a lesion state, the method comprising: a first step of setting ROI data on a lesion in an ultrasound image reflected from a target object; A third step of generating a fundamental image and a harmonic image from an ultrasonic echo signal for a target object, a third step of tracking the change in position of the lesion based on the ROI data in the fundamental image to generate modified ROI data, And quantifying the lesion in the harmonic image based on the ROI data.

The second step may include filtering the ultrasound echo signal in the frequency domain to separate the fundamental frequency signal and the harmonic frequency signal.

The second step may include generating the fundamental image and the harmonic image using the fundamental frequency signal and the harmonic frequency signal, respectively.

The third step may include generating motion data on a change in position of the lesion by comparing the estimated position of the lesion with the ROI data in the fundamental image and generating the modified ROI data using the motion data . ≪ / RTI >

The fourth step may include the steps of determining the location of the lesion in the harmonic image using the modified ROI data, measuring the concentration of the contrast agent distributed at the determined lesion location, and analyzing the measured concentration statistically And quantifying the lesion.

The fourth step may be a step of monitoring the change of the lesion state by quantifying the amount of the contrast agent imaged at the lesion site in the harmonic image.

And outputting the quantified data of the lesion to the screen in the form of one or more of numerical values, graphs and image types after the fourth step.

The lesion state monitoring method may be performed by a program for execution in a computer, and the program may be stored in the computer-readable recording medium.

According to an aspect of the present invention, there is provided a medical image system including a signal separator for generating a fundamental image and a harmonic image from an ultrasound echo signal for a target object injected with contrast agent, A motion estimation unit for tracking the change in position of the lesion in the fundamental image based on the ROI data and generating modified ROI data and a lesion measurement unit for quantifying the lesion in the harmonic image based on the corrected ROI data, .

The signal separator may separate the fundamental frequency signal and the harmonic frequency signal by filtering the ultrasonic echo signal in the frequency domain.

The signal separation unit may generate a corresponding fundamental image and a harmonic image using the fundamental frequency signal and the harmonic frequency signal, respectively.

The motion estimator may generate motion data on the change in position of the lesion by comparing the estimated position of the lesion with the ROI data in the fundamental image and generate the modified ROI data using the generated motion data .

The lesion measuring unit may determine the location of the lesion in the harmonic image using the modified ROI data, and quantify the lesion by measuring the concentration of the contrast agent distributed at the determined lesion location.

The lesion measuring unit may monitor the change of the lesion by quantifying the amount of the contrast agent imaged at the lesion site in the harmonic image.

The medical image system may further include an output unit for outputting the quantified data of the lesion on a screen in one or more of numerical values, graphs, and image types.

According to the present invention, it is possible to diagnose an objective lesion condition and evaluate the therapeutic effect by automatically tracking the lesion in the ultrasound image without qualitative evaluation of the user and quantifying the lesion, and it is possible to perform evaluation of the lesion in a subjective manner, The deviation of the result can be reduced.

1 is a block diagram of a medical image system according to an embodiment of the present invention.
2 is a flowchart illustrating a method of monitoring a lesion state using a medical image system according to an embodiment of the present invention.
3 is a diagram for explaining a process of separating a fundamental signal and a harmonic signal in the frequency domain.
FIG. 4 is a diagram for explaining a process of setting an ROI for a lesion in an ultrasound image obtained before inputting contrast agent.
FIG. 5 is a view for explaining a process of separating a fundamental image and a harmonic image from an ultrasound image obtained after inputting contrast agent.
FIG. 6 is a diagram for explaining a process of tracking an ROI by reflecting a change in the position of a lesion in a separated fundamental image.
FIG. 7 is a diagram for explaining a process of quantifying a lesion based on the position-corrected ROI.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a block diagram of a medical image system according to an embodiment of the present invention. The medical image system estimates the position of a lesion region on an ultrasound image obtained by reflecting ultrasound contrast agents (UCAs, hereinafter also referred to as agents) from a tissue in a human body in a state where the target body is implanted, The lesion is quantified and provided in consideration of the estimated movement of the lesion.

Specifically, a medical imaging system separates a fundamental frequency signal and a harmonic frequency signal from a frequency domain using an ultrasonic echo signal acquired from a target object after injecting a contrast agent, Generates a fundamental image and a harmonic image from the signal. The motion data of the target lesion is estimated by estimating the position change of the lesion on the fundamental image where the structural characteristics of the tissue are more clearly displayed, and the lesion area is measured and quantified by tracking the target lesion on the basis of the calculated motion data .

The medical imaging system includes a probe 110, a transceiver 120, a beamformer 130, an intermediate signal processor 140, a downstream signal processor 150, a controller 160, and an output unit 170 .

The probe 110 converts an electrical signal into an ultrasonic signal, transmits the ultrasonic signal to a target object, and converts the ultrasonic signal reflected from the target object into an electrical signal. Generally, the probe 110 is formed by combining a plurality of transducer elements. When an ultrasonic signal is emitted to a target by a transducer, if there is an interface having a different acoustic impedance among the propagation medium, a reflection phenomenon occurs at the interface, and a part of the ultrasonic signal is transmitted. When there are several interfaces, the ultrasonic echo is sequentially reflected It comes back. At this time, the reflected ultrasonic echoes apply pressure to the piezoelectric body of the transducer, generate an electric field proportional to the echo intensity, and convert it into an electric signal. One ultrasound pulse emitted to the object generates a pulse echo from each point at various depths (interface) within the object, where the ultrasound echo from the tissue at distance x, taking into account the pulse travel distance, = 2x / c (c = 1530m / s: mean sound speed). Therefore, the reflection position can be determined inversely from the delay time for this transmission pulse.

The transceiver 120 transmits the electric signal transmitted from the beam forming unit 130 to the probe 110 or converts the received electric signal for the ultrasonic echo reflected from the object to the beam forming unit 130. [ . At this time, the transceiver 120 may amplify the received electrical signal through a pre-amplifier.

The beam forming unit 130 forms a reception signal based on the electrical signal converted by the probe 110. That is, the beam forming unit 130 converts an analog signal generated from each transducer element of the probe 110 into a digital signal, and calculates a time interval for reaching each transducer element from the object, Adds the delay and then adds up to form a received signal.

The intermediate signal processor 140 processes the received signal and moves the received signal to the baseband frequency band. For this, the intermediate signal processing unit 140 is a DC removing unit 142. A demodulator 144, and an envelope detector 146.

The DC removing unit 142 removes a DC component from the formed received signal. The demodulator 144 demodulates the received signal, that is, a radio frequency (RF) signal, into a baseband signal to generate an in-phase signal component and a quadrature- ) Signal components. The envelope detector 146 performs an envelope detection process for detecting the size of the echo based on the received signal, that is, the ultrasound echo reflected from the object, to form an envelope signal. Here, the envelope signal may include coordinates on an X-Y coordinate system of a plurality of points existing on each scanning line, angle information of each scanning line with respect to the vertical scanning line, data obtained from each point, and the like.

The rear end signal processing unit 150 adjusts the ultrasound image signal that has passed through the intermediate signal processing unit 140 to be output to a display area of the output unit 170 as a desired ultrasound image. The rear end signal processing unit 150 includes a logarithmic conversion unit 162 and a scan conversion unit 164. The dynamic range of the ultrasound image signal that has passed through the demodulation unit 144 and the envelope detection unit 146 is input to the output unit 170, The dynamic range is adjusted by logarithm conversion using the logarithmic conversion unit 162 and the scan range of the display area of the output unit 170 in the scan conversion unit 164 is adjusted The ultrasound image data may be scan-converted so that the ultrasound image data can be output to the ultrasound image data.

All operations of the intermediate signal processor 140 and the rear-end signal processor 150 are processed in response to the real-time control of the controller 160. [ In particular, the controller 160 estimates a change in the position of the lesion area from the ultrasound image signal, and measures and quantifies the lesion area. When a low-energy ultrasonic signal is transmitted to the object, the contrast agent vibrates and a harmonic frequency signal is generated. The controller 160 separates the harmonic frequency signal from the reflected ultrasound echo signal to generate a harmonic image and measure the amount of micro-bubble based on the intensity of the generated harmonic image. For this, the controller 160 may include a signal separator 162, a motion estimator 164, and a lesion measurer 166.

The signal separator 162 separates the fundamental frequency signal and the harmonic frequency signal by filtering the ultrasound echo signal of the object injected with the contrast agent in the frequency domain, The fundamental image and the harmonic image are generated using the fundamental frequency signal and the harmonic frequency signal, respectively.

In this regard, Fig. 3 shows an example of the distribution in the frequency domain of the RF data of the ultrasonic echo signal. Referring to FIG. 3, the signal separator 162 sets a boundary value T10 for filtering a fundamental frequency signal and a harmonic frequency signal, and performs filtering (T20) of a fundamental frequency signal and filtering (T30). At this time, a band pass filter (BPF) may be used to separate the two signals, or a high pass filter (HPF) or a low pass filter (LPF) may be used.

The motion estimation unit 164 tracks the change in the position of the lesion in the fundamental image based on the ROI (Location Of Interest) data for the lesion set before injecting the contrast agent, and generates the modified ROI data. Since the fundamentals image is an image of signals generated in the surrounding tissues of lesions and lesions, the shape and position information of lesions can be extracted from the fundamentals image. Specifically, the motion estimation unit 164 generates ROI data corresponding to the lesion location information in the ultrasound image of the target object before the contrast agent is injected, and then generates the ROI data after the contrast agent is injected and separated from the signal separation unit 162 The motion data indicating the degree of motion of the target lesion can be calculated by estimating the position change of the lesion in the fundamentals image and the ROI data having the corrected position of the lesion can be generated based on the calculated motion data. At this time, the change of the position of the lesion may occur when the probe 110 closely attached to the target object moves, or when the target object breathes or the like. In some cases, the motion estimation unit 164 may generate and manage only motion data instead of generating corrected ROI data.

The lesion measuring unit 166 specifies the position of the lesion in which the positional change is corrected in the plurality of harmonic images by using the ROI data or the motion data corrected for the positional change and measures the concentration of the harmonic image at the specified position. Ultrasound pulses of low energy generate harmonic frequency signals by the vibration of the contrast agent, so that the higher the concentration of the harmonic image, the more likely the contrast agent is distributed and the lesion is present. Accordingly, the lesion measurement unit 166 can measure the amount of microbubbles based on the concentration of the harmonic image and analyze the amount of microbubbles to quantify the lesion state. At this time, as a method for quantifying the state of the lesion, the average value of the intensity in the lesion area is calculated, or the lesion area is divided into a plurality of areas, and the concentrations in the respective areas are respectively measured, And various quantification methods such as an average value or quantification by other methods can be considered. In addition, the lesion measurement unit 166 can sequentially track the change in the state of the lesion and provide a result of a quantitative measurement result of an accurate lesion.

The output unit 170 outputs ultrasound image data processed by the controller 160 or the downstream signal processing unit 150 to a display area of the output unit 170. At this time, the output unit 170 may display the quantified data of the lesion on a screen in the form of a numerical value, a graph, or an image.

Next, a process of monitoring the lesion state using the medical image system having the above-described configuration will be described.

FIG. 2 shows a method for monitoring a lesion state according to an embodiment of the present invention.

As shown in the figure, when the reflected echo signal of the ultrasonic wave received by the object through the beam forming unit 130 is received by the probe 110, the received ultrasonic echo signal passes through the DC component removing step and the quadrature demodulating step, Band, and the envelope detection process is performed (S100).

If the input RF data is the first ultrasound image or the ultrasound image designated by the user, the control unit 160 generates ROI data that is basic in the image (S110, S120). The ultrasound image for generating the ROI data may be an initial ultrasound image or an ultrasound image selected by the user at an arbitrary point before the injection of the contrast agent. FIG. 4 shows an example in which the ROI data is set by designating the position of the lesion in the ultrasound image before the contrast agent is injected.

Then, when the contrast medium is injected into the subject, the contrast medium moves through the bloodstream and collects in the blood vessels around the cancer cells. 5 (a), it can be seen that a lot of contrast agents are particularly distributed around the lesion. The signal separator 162 separates the fundamental ultrasound signal and the harmonic ultrasound signal from the input RF data and outputs a fundamental image and a harmonic An image is generated (S130). 5 (b) and 5 (c) show separately generated fundamentals and harmonic images. As can be seen in FIG. 5 (c), lesion tissue is not clearly distinguished on the harmonic image, so the lesion position is set on the fundamental image.

At this time, the motion estimating unit 164 obtains the position of the lesion matched on the fundamental image based on the previously set ROI data, generates motion data related to the position change of the lesion, and based on the generated motion data The ROI data may be modified (S140). Fig. 6 (a) shows the ROI data as a base, and Fig. 6 (b) shows ROI data after position correction.

Then, the lesion measuring unit 166 measures the concentration of the harmonic image at the position of the corrected ROI data, that is, the concentration of the contrast agent, and quantifies the lesion on the harmonic image based on the temporal change or the morphological change thereof (S150). Such a procedure can be repeatedly performed at predetermined time intervals after the injection of the contrast agent, and it is possible to accumulate the change in the state of the lesion after the injection of the contrast agent, and to provide the result in the form of a numerical value, an image or a graph.

In such a medical image system, the user can visually observe the diffusion of the contrast agent on the ultrasound image, and instead of making a qualitative evaluation of the lesion, the lesion is automatically tracked and quantified in the image, It is possible to exclude individual characteristics such as differences and to obtain an objective diagnosis result.

In addition, it is possible to track and evaluate the therapeutic effect through improvement of objectivity of lesion evaluation based on the quantification of lesions, and as a basis for finding the optimal treatment method through quantitative comparison of treatment effects of various treatments Can be utilized.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. That is, within the scope of the present invention, all of the elements may be selectively coupled to one or more of them.

In addition, although all of the components may be implemented as one independent hardware, some or all of the components may be selectively combined to perform a part or all of the functions in one or a plurality of hardware. As shown in FIG. The codes and code segments constituting the computer program may be easily deduced by those skilled in the art. Such a computer program can be stored in a computer-readable storage medium, readable and executed by a computer, thereby realizing an embodiment of the present invention. As the storage medium of the computer program, a magnetic recording medium, an optical recording medium, a carrier wave medium, or the like may be included.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. It should be noted that the embodiments disclosed in the present invention are not intended to limit the scope of the present invention and are not intended to limit the scope of the present invention. Accordingly, the scope of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as being included in the scope of the present invention.

Claims (15)

A method for monitoring a condition of a lesion,
A first step of setting ROI data on a lesion in an ultrasound image reflected from a target object;
A second step of generating a fundamental image and a harmonic image from the ultrasound echo signal for the object in a state in which the contrast agent is injected into the object;
A third step of tracking the change in position of the lesion based on the ROI data in the fundamental image to generate modified ROI data; And
And quantifying the lesion in the harmonic image based on the modified ROI data.
How to monitor disease status. The method according to claim 1,
The second step comprises:
And filtering the ultrasound echo signal in the frequency domain to separate the fundamental frequency signal and the harmonic frequency signal.
How to monitor disease status. 3. The method of claim 2,
Wherein the second step includes generating the fundamental image and the harmonic image using the fundamental frequency signal and the harmonic frequency signal, respectively,
How to monitor disease status. The method according to claim 1,
In the third step,
Comparing the estimated position of the lesion with the ROI data in the fundamental image to generate motion data related to a change in the position of the lesion; And
And generating the modified ROI data using the motion data.
How to monitor disease status. The method according to claim 1,
In the fourth step,
Determining a position of the lesion in the harmonic image using the modified ROI data;
Measuring the concentration of the contrast agent distributed at the determined lesion location; And
And analyzing the measured concentration statistically to quantify the lesion.
How to monitor disease status. The method according to claim 1,
Wherein the fourth step is a step of quantifying the amount of contrast agent imaged at the lesion site in the harmonic image,
How to monitor disease status. The method according to claim 1,
Further comprising, after the fourth step, outputting the quantified data of the lesion to the screen in one or more of numerical, graphical, and image forms.
How to monitor disease status. A computer-readable recording medium storing a program for causing a computer to execute the method according to any one of claims 1 to 7. A medical imaging system for monitoring a condition of a lesion,
A signal separator for generating a fundamental image and a harmonic image from an ultrasound echo signal for a target object injected with contrast agent;
A motion estimator for tracking the change in the position of the lesion in the fundamental image based on ROI data of the lesion set before injecting the contrast agent to generate modified ROI data; And
And a lesion measurer for quantifying the lesion in the harmonic image based on the modified ROI data.
Medical imaging system. 10. The method of claim 9,
Wherein the signal separator separates the fundamental frequency signal and the harmonic frequency signal by filtering the ultrasonic echo signal in the frequency domain,
Medical imaging system. 11. The method of claim 10,
Wherein the signal separation unit generates a fundamental image and a harmonic image corresponding to the fundamental frequency signal and the harmonic frequency signal,
Medical imaging system. 10. The method of claim 9,
Wherein the motion estimator compares the estimated position of the lesion with the ROI data in the fundamental image to generate motion data related to the positional change of the lesion and generates the modified ROI data using the generated motion data,
Medical imaging system. 10. The method of claim 9,
Wherein the lesion measuring unit determines the position of the lesion in the harmonic image using the modified ROI data and measures the concentration of the contrast agent distributed at the determined lesion location to quantify the lesion,
Medical imaging system. 10. The method of claim 9,
Wherein the lesion measuring unit monitors the change in the lesion state by quantifying the amount of the contrast agent imaged at the lesion location in the harmonic image,
Medical imaging system. 10. The method of claim 9,
Further comprising an output unit for outputting the quantified data of the lesion to the screen in the form of one or more of numerical values,
Medical imaging system.

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