JP2007518508A - Ultrasound imaging system for calculating compressibility - Google Patents

Abstract

The present invention relates to an ultrasound imaging system for calculating the compression rate of an object of interest located in a region of a patient's body that is scanned by an ultrasound probe. The system according to the present invention comprises a compression means (1) for compressing a patient area, and a first ultrasonic examination image and a second ultrasonic examination image of the object of interest before and during compression, respectively. An acquisition means (3) for acquiring; the first height of the noted object in the first ultrasonic examination image; and the second height h ₂ of the noted object in the second ultrasonic examination image. Measuring means (11) for measuring the above and a calculating means for obtaining a compression ratio from the first and second heights. The compression rate is used, for example, to identify fat leaflets in the chest.

Description

  The present invention relates to an ultrasound imaging system for calculating the compression rate of an object of interest. The invention further relates to the use of such a system. The present invention finally relates to a computer program for realizing such a method.

  Several methods are commonly used for early detection of breast cancer. Historically, early methods have been palpation methods (commonly known as self-chest diagnosis or SBE) performed regularly by the patient himself to detect any changes in breast structure, or abnormalities in the chest There is a palpation method by a doctor looking for nodule (lump).

  In recent years, several countries, including the United States, have introduced systematic inspection programs using X-ray mammography. X-ray mammography is a very sensitive technique, except when the breast tissue is dense, and can find a mass as small as 5 mm, that is, a very early stage cancer. However, X-ray mammography detects a number of false warnings that can be normal tissue with an obscure morphology such as fatty lobule or benign lesions such as cysts or fibroadenoma. In order to reject such false warnings without using a biopsy, ultrasound is usually used as an adjunct to mammography. 1A, 1B, and 1C show examples of ultrasonographic images having fibroadenoma FA, fatty lobule FL, and cancer C, respectively.

US Ultrasound Medical Conference (AIUM) available on CD-ROM sold at http://www.aium.org/products/store/_productDetail.asp?id=02CTBUCD&cat=B&words=&pg=1 In the course of, a conventional sonographer and radiologist will demonstrate a prior art chest ultrasound. In one such demonstration, the sonographer explains that a normal structure, such as a fat leaflet, can be mistaken for a lesion. Since fat is very common in the breast, having a fast and reliable way of identifying fat leaflets is a top priority. The sonographer explains a principle-based approach that applies to palpation. In other words, it is a technique based on the difference in the elasticity characteristics of the tissue. In fact, the fatty lobule is made of normal and easily deformable tissue and thus exhibits a higher compression rate than abnormal tissue such as fibroadenoma, and even cancer. Such calculation of the compression rate is performed manually by an ultrasonic diagnostician. In fact, the ultrasound diagnostician method is:
Obtaining a first ultrasound image of the chest where an abnormal nodule is visible;
-In the first ultrasonography image, the superior edge point belonging to the upper edge of the abnormal nodule and the inferior edge point belonging to the lower edge of the abnormal nodule A step to choose;
-Calculating the first height of the abnormal nodule as the distance between its upper and lower edge points;
Applying compression to the chest in the area containing the abnormal nodule;
Obtaining a second ultrasound image of the chest during compression;
-Measuring the second height of the abnormal nodule in the second ultrasound examination image in the same manner as described above;
-Calculating the compression ratio as a ratio between the first height and the second height.

  Abnormal nodules with a predetermined threshold, usually greater than 30%, are considered fat leaflets and are rejected.

  The disadvantage of such manual calculation of the compression ratio is that it is boring and time consuming for the ultrasound diagnostician.

  It is an object of the present invention to provide a more efficient solution that automatically calculates the compression ratio of an object of interest using ultrasonic imaging techniques.

This purpose is
-Compression means for compressing the area of the patient's body;
-Using the ultrasonic probe, obtain a first ultrasonic examination image before compression and a second ultrasonic examination image during compression for a target of interest located in the above-mentioned region in the patient's body. Acquisition means to
Measuring means for measuring the first height of the noted object in the first ultrasonic examination image and the second height of the noted object in the second ultrasonic examination image;
-Achieved by an ultrasound imaging system comprising a calculating means for obtaining a compression ratio from the first and second heights described above.

  In accordance with the present invention, the user needs to manually select a first set of upper and lower edge points in the first ultrasound image, such edge points to obtain a first height. it is not necessary to measure the distance between the points), to repeat the processing in the second ultrasound image to obtain the second height, and to calculate the compression ratio from the first and second heights. . The user can even apply compression to the region of interest on the patient's body and indicate when the first and second ultrasound images must be taken, for example by pressing a button. do it. With the ultrasonic imaging system according to the present invention, the compression rate is immediately calculated and displayed from the first and second ultrasonic examination images. Thus, the involvement of the ultrasound diagnostician is greatly reduced and the procedure is speeded up.

  Furthermore, the procedure for measuring the first and second heights based on the image processing technique is objective and is performed in the same manner for any set of first and second ultrasound images. On the other hand, in the prior art, manual selection of the first and second heights is subjective, depending on the interpretation of the ultrasound diagnostician. Therefore, according to the present invention, the height measurement can be made more reproducible.

  In the first embodiment of the present invention, a local approach is proposed. The measuring means according to the invention has detection sub-means for detecting the upper and lower edge points in the profile based on the direction of the ultrasonic beam. Height is measured as the Euclidean distance between its upper and lower edge points. Such a procedure is repeated in the second ultrasonic diagnostic image. Such local approaches mimic the manual procedures described in the prior art in an automatic manner and include image processing techniques. The advantage of this first embodiment of the present invention is simplicity.

  In the first variant of the first embodiment of the present invention, a plurality of cross-sections are considered in the first and second ultrasound diagnostic images, and therefore a plurality of heights are measured in both ultrasound diagnostic images. Is done. The system according to the invention further comprises means for averaging the plurality of measured heights. The advantage lies in obtaining a more robust measurement with respect to height and thus obtaining a more accurate calculation with respect to the compression ratio of interest.

  In a second variant of the first embodiment of the invention, the system according to the invention comprises fitting means for fitting a surface curve to the aforementioned plurality of edge points. The surface curve model advantageously relies on a priori knowledge about the object of interest. For fat leaflets, for example, an elliptical model is used. The first advantage of this second variant is that the detected abnormal edge can be rejected. A second advantage is that additional geographic measurements, for example surface measurements, can be made on the object of interest in order to make the deformation description more accurate.

  In the second embodiment of the present invention, a region-based approach is proposed. The measuring unit according to the present invention includes a dividing unit that segments a target of interest having a predetermined shape in an ultrasonic examination image. For a fat leaflet, the predetermined shape is, for example, an ellipse. The advantage of the second embodiment of the present invention is that when there are a plurality of objects of interest, matching between the first shape and the second shape corresponding to the object of interest in each of the first and second ultrasonic diagnostic images is performed. It is a point that makes it easy.

  These and other aspects of the invention will be apparent from and will be elucidated with reference to the embodiments described herein.

  The invention will now be described in more detail by way of example with reference to the corresponding drawings.

  The present invention relates to an ultrasound imaging system for measuring a compression rate of an object of interest. Such a system is particularly adapted for medical image processing, and in particular for the diagnosis of breast cancer with ultrasound diagnostic images of the chest.

FIG. 2 gives an overview of an ultrasound imaging system according to the present invention. The ultrasound probe 1 includes a multi-element transducer array 2 that transmits a wave of ultrasound energy into a patient's body and receives ultrasound echoes returning from the structure within the body. The internal structure is, for example, a target of attention in the chest. The ultrasound probe 1 staggers the individual elements of the transducer array 2 to form and steer the ultrasound beam, and receives and amplifies echo signals received by the transducer elements following each pulse transmission. And connected to an acquisition means 3 having a transmitter / receiver 4 to be digitized. The transmitter / receiver 4 is coupled to a beamformer 5 that controls the time at which the transmitter / receiver 4 activates the elements of the transducer array 2. The beamformer 5 also receives the digitized echo signals generated by the transmitter / receiver 4 during echo reception and approximately delays and sums them to form a coherent echo signal. The beamformer 5 applies to the image processor 6 which spatially processes the amplitude information of the echo signal for the formation of the ultrasound diagnostic image I ₁ of the tissue in the region scanned in the patient. Connected. The intensity values of the ultrasound diagnostic image are applied to a scan converter and display processor 7 that spatially arranges the intensity values in the desired image format. The ultrasonic diagnostic image I ₁ is stored in the image sequence memory 7 and displayed on the display screen 8.

  The system according to the invention further comprises means for applying compression to the patient's body, just in the scanned area. In the present application, the ultrasound probe 1 is used to apply a press to the chest, so that the press is applied in the scanning direction of the ultrasound beam. However, it should be noted that mechanical devices can be used as well. In this latter case, the direction of compression may be different from the direction of the ultrasonic beam.

The system according to the invention further comprises a user interaction means 10 that allows the user to interact with the system. In particular, the user can click on a button to activate the acquisition means 3 and obtain a new ultrasound diagnostic image. In this application, the user must command acquisition of the _second ultrasound diagnostic image I ₂ during compression in the same region of the patient's body.

The system according to the invention further comprises measuring means 11 for measuring the height of the object of interest in the ultrasound diagnostic image. When the first ultrasound diagnostic image I ₁ before compression and the second ultrasound diagnostic image I ₂ after compression in the same region in the chest are acquired, the measuring unit 11 performs the first and second measurements. It is possible to measure the first height h ₁ and the second height h ₂ of the object of interest in each of the ultrasonic diagnostic images (I ₁ , I ₂ ). The first height h ₁ and the second height h ₂ described above are used by the calculation means 12 that calculates the compression rate of the target object.

  FIG. 3A is a schematic view of the ultrasound probe 1 placed in contact with the region of the chest skin 20. At this position, the ultrasonic beam generated by the ultrasonic probe 1 scans the scanning region 21 having at least the target object 22. The attention object is a nodule, for example.

  FIG. 3B is a schematic diagram showing the ultrasound probe 1 during compression of the same region of the chest. As already mentioned above, compression is advantageously applied via the ultrasound probe 1 to the chest region of interest. Therefore, in this case, the direction of compression corresponds to the direction of the ultrasonic beam.

In the first embodiment of the present invention shown in FIGS. 3A to 3D, the measuring means 11 includes a _{first set} of edge points (E ₁₁ , E ₁₂ ) in the first ultrasonic diagnostic image I ₁ , and Detection sub-means for detecting a second set of edge points (E ₂₁ , E ₂₂ ) in the second ultrasonic diagnostic image I ₂ . The first edge point (E ₁₁ , E ₂₁ ) corresponds to the edge point reached at the first time by the transmitted ultrasonic beam, and the second edge point (E ₁₂ , E ₂₂ ) Note that it corresponds to the edge point reached at a second time by the ultrasound beam.

Under the effect of compression, the object of interest 22 is more or less deformed. The degree of deformation mainly depends on the strength of compression and the strength of the structure related to the target object 22. As shown in FIG. 3B, the second height h ₂ is, for example, along the cross section P ₁ ′ corresponding to the position of the cross section P ₁ with respect to the reference (O, x, y) of the ultrasonic probe 1, Measured during compression on the _second ultrasound diagnostic image I2.

3C and 3D show intensity curves IC ₁ and IC ₁ ′ corresponding to the cross sections P ₁ and P ₁ ′, respectively. Advantageously, the measuring means 11 further comprises a smoothing sub-means for smoothing the intensity curves IC1, IC1 ′ before detection of the edge points (E ₁₁ , E ₁₂ , E ₂₁ , E ₂₂ ). The smoothing sub means includes, for example, a low-pass filter using a Gaussian kernel. Smoothed intensity curves SIC ₁ and SIC ₁ ′ are obtained. The advantage is that these smoothed intensity curves are less noisy.

  Sub-detection means include, for example, techniques for maximizing the gradient, which are well known to those skilled in the art.

  As a variant, the local edge detection provided by the detection sub-means can advantageously be replaced by adapting the intensity curves IC1, IC1 'to a predetermined shape, for example a negative Gaussian kernel. Such adaptation is achieved by adjusting the mean and standard deviation, which are characteristics of the Gaussian kernel. When the cross-sectional size is normalized, the position of the most suitable fitted Gaussian kernel indicates the position of interest and its edge points are easily obtained therefrom. The advantage of such a modification is that there are few local surfaces. In particular, this solution takes into account the fact that the intensity curve of interest first has a down step followed by an up step. Detection can be made more robust for ultrasound diagnostic images having multiple objects of interest that tend to appear in the same intensity curve.

Regarding the cross sections P ₁ and P ₁ ′, the height (h ₁ , h ₂ ) is the position of the lower edge points E ₁₂ and E ₂₂ (y ₁₂ , y ₂₂ ) and the position of the upper edge points E ₁₁ and E ₂₁ (y ₁₁ , y ₂₁ ) is subtracted from it, which is:
h ₁ = (y ₁₂ -y ₁₁ )
h ₂ = (y ₂₂ -y ₂₁ )
It is. Here, y ₁₁ , y ₁₂ , y ₂₁ , y ₂₂ are y coordinates of edge points E ₁₁ , E ₁₂ , E _21, and E ₂₂ with respect to the reference (O, X, Y) of the ultrasonic probe. .

The calculating means 12 is intended to calculate the compression ratio CR from the measured first and second heights h ₁ and h ₂ as follows:

The compression rate CR is expressed as a ratio, for example, and is displayed together with the first and / or second ultrasonic diagnostic images I ₁ and I ₂ . As already mentioned above, such a compression ratio CR can be advantageously compared with normal numbers associated with a priori knowledge and used to identify the subject of interest.

  In certain cases of chest ultrasound images, distinguish breast cancer from other types of subjects of interest that may have a very similar appearance in chest ultrasound images, such as fatty lobule and fibroadenoma Is the purpose. Compression rate knowledge allows fat leaflets to be rejected with a high level of reliability. In fact, fat leaflets are made of adipose tissue and are normal and deformed tissue. Conversely, cancer is a lesion composed of hard tissue, also called a solid mass, and cannot be easily deformed. As a result, it has been empirically established that nodules with a compression rate of 30% or more are fat leaflets and should be rejected.

In a variant of the first embodiment of the invention, the measuring means 11 are intended to measure the first and second heights in a plurality of cross sections instead of one cross section. 4A to 4D, three cross sections P1, P2, P3 and three cross sections P1 ′, P2 ′, P3 ′ are considered in the first and second ultrasonic diagnostic images I ₁ and I _2, respectively. Is done. The measurement of the heights h ₁₁ , h ₂₁ , h ₃₁ , h ₁₂ , h ₂₂ and h ₃₂ is repeated by the measuring means 11 for each cross section P1, P2, P3 and P1 ′, P2 ′, P3 ′. The measuring means 11 further measures the first height h ₁₁ , h ₂₁ , h ₃₁ measured in the first ultrasonic diagnostic image I ₁ and the second ultrasonic diagnostic image I _{2 with} respect to the target object. And averaging second means for averaging the second heights h ₁₂ , h ₂₂ and h ₃₂ . Average heights h _1a and h _2a are obtained, which further contributes to the calculation of the compression ratio CR.

  The first advantage of this modification is that it is more robust against local variations in deformation. As shown in FIG. 4B, when compression is applied to the patient's body, the subject of interest may have locally different deformations.

The second advantage of this modification is that it deals with the lateral displacement that the object of interest may have under the effect of compression. Therefore, the cross-section P ₁ ′ before compression does not intersect with the target object at the same position as the cross-section P _{1 being} compressed. However, the plurality of cross sections can cover the entire object of interest.

When the target object completely leaves the scanning region of the ultrasonic beam, it is considered that the user repeats the acquisition procedure to obtain a set of ultrasonic diagnostic images (I ₁ , I ₂ ) including the target object.

In another modification of the first embodiment of the present invention, the measuring means 11 applies a contour curve of a predetermined shape to the edge points detected in the first and second ultrasonic diagnostic images I ₁ and I ₂ . Has an adaptation means to adapt. The contour curve of a predetermined shape is selected based on the a priori knowledge about the searched target object. Referring to FIGS. 5A and 5B, an elliptic curve is selected for breast cancer. The first elliptic curve 41 is adapted to the contour of the target of interest in the _first ultrasonic diagnostic image I ₁ , and the second elliptic curve 42 is the contour of the target of interest corresponding to the _second ultrasonic diagnostic image I ₂ . Is adapted to.

The first advantage is that the compression rate is estimated more accurately even if the object of interest moves under compression. For example, the compressibility can be calculated as the ratio of the maximum thickness in the fitted ellipse that can be at different locations under the probe in the ultrasound diagnostic images I ₁ and I ₂ .

The second advantage is that the estimation of the first surface S ₁ and the second surface S ₂ of interest in the _first and _second ultrasound diagnostic images I ₁ and I ₂ respectively can be estimated. The deformation model can be applied. Thus, such surface estimation not only makes it possible to calculate the compression ratio, but also makes it possible to obtain other deformation measurements such as the elastic force of interest.

In the second embodiment of the present invention, the measuring unit 11 includes a dividing unit that divides a region with a model having a predetermined shape in an ultrasonic diagnostic image. In a particular application of chest ultrasound diagnostic images, the object of interest is advantageously retrieved as a dark oval shape on a light background, as shown in FIGS. 6A and 6B. For example, a segmentation technique based on the generalized Hough transform will detect all possible ellipses in the image. Another possibility would be to apply a region growing technique and select those with an elliptical shape at all minima of the intensity of the image representing the dark area. The third possibility is to design an active contour that is subject to an internal force that favors the elliptical shape and an external force that attaches it towards the high gradient boundary, and all dark It will evolve to match the boundaries of the region. Using any or similar of such methods, multiple ellipses can be detected in the ultrasound diagnostic images I ₁ and I ₂ . Advantageously, the measuring means 11 further comprises a first segment shape Sh ₁ , Sh ₂ , Sh ₃ or Sh ₄ in the first ultrasound diagnostic image I ₁ and a second in the second ultrasound diagnostic image. There is an association means for associating the divided shapes Sh ₁ ′, Sh ₂ ′, Sh ₃ ′, or Sh ₄ ′. The association means described above are mainly based on a set of conditions expressed as localization and geometric parameters obtained from deductive medical knowledge. This condition set includes, but is not limited to, the following assumptions:
-Fat leaflets are wide rather than tall. Therefore, the main dimensions of the first and second divided shapes (Sh ₁ , Sh ₁ ′), (Sh ₂ , Sh ₂ ′), (Sh ₃ , Sh ₃ ′) must be horizontal. .
The second divided shapes Sh ₁ ′, Sh ₂ ′, Sh ₃ ′ represent the target object after compression. Therefore, they must be flatter than the first split shapes Sh ₁ , Sh ₂ , Sh ₃ .
-The subject of interest should not move much during compression. Therefore, the positions of the first and second divided shapes (Sh ₁ , Sh ₁ ′), (Sh ₂ , Sh ₂ ′), (Sh ₃ , Sh ₃ ′) should be close to each other.

The first advantage of approximating the shape of the object of interest with a model of a predetermined shape is that the geometric parameters of the model of the predetermined shape are well known. Therefore, they are used to select the most appropriate first and second heights (h ₁ , h ₁ ′) in the first and second ultrasound diagnostic images (I ₁ , I ₂ ). be able to. For example, the first height h ₁ is the maximum thickness of the first divided ellipse Sh ₁ , and the second height h ₁ ′ is the maximum thickness of the second divided ellipse Sh ₁ ′. is there. Therefore, the estimation of the compression rate becomes more robust with respect to any displacement of the target object due to compression.

  The second advantage of the second embodiment of the present invention is that it is more robust with respect to a large number of objects of interest in the ultrasound diagnostic image. In fact, if some of the objects of interest are close in the first and second ultrasound diagnostic images, the detection means according to the first embodiment of the present invention may cause some errors. This is because the cross section includes edges belonging to several objects of interest. On the other hand, the detection means by the 2nd Embodiment of this invention can distinguish between different attention object.

  A third advantage of the second embodiment of the present invention is that it makes it possible to make other measurements, eg elasticity measurements, regarding the compression of the object.

In a third embodiment of the invention, the compression means is intended to apply a continuous press to the area of interest on the chest. Referring to FIG. 7, new second ultrasound diagnostic images I ₃ and I ₄ are obtained for the new press, respectively, and the measurement of the second heights h ₃ and h ₄ is performed on the new second This is performed on the ultrasonic diagnostic image. The system according to the invention further comprises compression averaging means for averaging the second heights h ₂ , h ₃ and h ₄ . A second average height h _234a is obtained, which is used to calculate the compression ratio. The average is that continuous presses applied manually by the user to the region of interest are averaged. This compensates for variations in intensity applied to manual compression from one time to another. Therefore, the comparison of the compression rate values is made more reliable. Note that the time required to calculate the compression ratio from the compression sequence increases, but this is made acceptable by the time gain provided by the system according to the invention.

Referring to FIG. 8, the present invention also relates to an ultrasonic imaging method for determining the compression rate of interest, which method includes:
- a step 70 of obtaining the first ultrasonic diagnostic image I ₁ of the focused target 71 positioned in the region of the body of the patient to be scanned by the ultrasonic probe 1,
-Step 72 of compressing said subject of interest;
- a step 73 of the second ultrasonic diagnostic image I ₂ to get between the object of interest of the compression,
Measuring the first height h ₁ of the target of interest in the first ultrasonic diagnostic image I ₁ and the second height h ₂ of the target of interest in the second ultrasonic diagnostic image I ₂ And steps to
A step 74 of calculating the compression rate CR of the object of interest from the first and second heights (h ₁ , h ₂ ).

  The drawings and their descriptions in this document serve to illustrate the invention and not to limit it. It will be apparent that there are many variations that fall within the scope of the appended claims. In this regard, the following conclusions are made: there are many ways to implement functionality using items of hardware and / or software. In this respect, the drawings are just diagrams, each representing only one possibility of an embodiment of the present invention. Thus, although the drawings show different functions as different blocks, this in no way excludes that a single item of hardware or software performs several functions, and a single function Neither does it preclude being performed by a collection of items of software or both.

  Any reference signs in the claims should not be construed as limiting the claim. The word “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element or step does not exclude the presence of a plurality of such elements or steps.

It is a figure which shows the example of the ultrasonic diagnostic image which has a fibroadenoma, a fatty lobule, and cancer. It is a figure which shows the example of the ultrasonic diagnostic image which has a fibroadenoma, a fatty lobule, and cancer. It is a figure which shows the example of the ultrasonic diagnostic image which has a fibroadenoma, a fatty lobule, and cancer. 1 is a schematic diagram of an ultrasound imaging system according to the present invention. It is the schematic which shows how the 1st and 2nd height in an attention object is measured by the system by the 1st Embodiment of this invention. It is the schematic which shows how the 1st and 2nd height in an attention object is measured by the system by the 1st Embodiment of this invention. It is the schematic which shows how the 1st and 2nd height in an attention object is measured by the system by the 1st Embodiment of this invention. It is the schematic which shows how the 1st and 2nd height in an attention object is measured by the system by the 1st Embodiment of this invention. FIG. 3 is a schematic diagram showing several cross-sections for measuring and averaging the first and second heights of interest based on the first embodiment of the present invention. FIG. 3 is a schematic diagram showing several cross-sections for measuring and averaging the first and second heights of interest based on the first embodiment of the present invention. FIG. 3 is a schematic diagram showing several cross-sections for measuring and averaging the first and second heights of interest based on the first embodiment of the present invention. FIG. 3 is a schematic diagram showing several cross-sections for measuring and averaging the first and second heights of interest based on the first embodiment of the present invention. It is the schematic which shows the approximation by the elliptic curve of the outline of an attention object based on the 1st Embodiment of this invention. It is the schematic which shows the approximation by the elliptic curve of the outline of an attention object based on the 1st Embodiment of this invention. It is the schematic which shows a mode that an attention object is divided with the model of a predetermined shape in the 1st and 2nd ultrasonic diagnostic image based on the 2nd Embodiment of this invention. It is the schematic which shows a mode that an attention object is divided with the model of a predetermined shape in the 1st and 2nd ultrasonic diagnostic image based on the 2nd Embodiment of this invention. FIG. 6 is a schematic diagram showing continuous compression of an object of interest based on a third embodiment of the present invention. Fig. 2 is a schematic diagram illustrating a method according to the present invention.

Claims (10)

An ultrasound imaging system,
-Compression means for compressing the area of the patient's body;
-Acquisition using an ultrasound probe to acquire a first ultrasound diagnostic image before compression and a second ultrasound diagnostic image being compressed for a target of interest located in the region of the patient's body Means,
Measuring means for measuring a first height of the target object in the first ultrasonic diagnostic image and a second height of the target object in the second ultrasonic diagnostic image;
-A system comprising calculation means for obtaining a compression ratio from the first and second heights.   Sub-detection means for detecting the upper edge point and the lower edge point in the first and second ultrasonic diagnostic images on at least one cross-sectional line facing the direction based on the scanning direction of the ultrasonic probe. And the first and second heights are calculated as a distance between the upper edge point and the lower edge point in each of the first and second ultrasonic diagnostic images. The ultrasound imaging system of claim 1.   The detection means is configured to detect the upper edge point and the lower edge point on a plurality of cross-sectional lines in order to give a plurality of first and second heights, and the measurement means includes the measurement The ultrasound imaging system according to claim 2, further comprising averaging sub-means for calculating a first average height and a second average height from the plurality of measured first and second heights.   The ultrasonic imaging system according to claim 3, wherein the measuring unit includes a fitting unit that adapts a curved contour having a predetermined shape to the plurality of detected first and second edge points.   A division sub-unit for dividing the first predetermined shape surface of the target object in the first ultrasonic diagnostic image and the second predetermined shape surface of the target object in the second ultrasonic diagnostic image by the measuring unit. The ultrasound imaging system of claim 1, comprising:   6. The ultrasound imaging system of claim 5, wherein the measuring means comprises association sub- means for associating the first predetermined shape surface with the second predetermined shape surface.   6. The ultrasound imaging system according to claim 4 or 5, wherein the calculating means is adapted to calculate a surface-based compressibility from the first and second predetermined shaped surfaces.   The ultrasound imaging system of claim 1, wherein the compression is applied to the region of the patient's body using the ultrasound probe as a piston. In the ultrasonic imaging method for measuring the compression rate of the target object,
-Using a ultrasound probe placed on the patient's body to obtain a first ultrasound diagnostic image of the object of interest located on the patient's body;
-Compressing the object of interest;
Obtaining a second ultrasound diagnostic image during compression of the object of interest;
Measuring the first height of the target of interest in the first ultrasonic diagnostic image and the second height of the target of interest in the second ultrasonic diagnostic image;
Obtaining the compression rate of the object of interest from the first and second heights.   A computer program having a set of instructions that, when loaded into a processor, causes the processor to perform the method of claim 9.

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