JP4352449B2 - Image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a region extraction method, a region display method, and an image display device, and in particular, extracts a region such as a heart ventricle and myocardium by computer processing of an MR image and a CT image, and displays the region extraction method and region display. The present invention relates to a method and an image display device.
[0002]
The present invention also relates to an image display method and apparatus, and more particularly to an image display method and apparatus for displaying a medical image such as a tomogram.
[0003]
Furthermore, the present invention relates to a region extraction method and apparatus, and more particularly to a region extraction method and device for extracting a specific region from an image.
[0004]
[Prior art]
A bullseye display has been used as a conventional method for displaying changes in the heart wall thickness of the heart (for example, see Non-Patent Document 1).
[0005]
The bullseye display is a technique in which functional information of the heart is represented by a concentric map and is developed on polar coordinates composed of depth and angle. This depth represents the cross-sectional position of the heart, and the distance from the center of the pulls eye display unit corresponds to the depth.
[0006]
The value recorded on the bullseye display is a representative value such as the maximum value or the average value in the vicinity of the automatically extracted intima surface, for example, within 1 cm from the surface, and indicates the state of heart wall motion. And those obtained on the basis of the shadow by the harmonic method using a contrast agent.
[0007]
As an area extraction method and apparatus for extracting a specific area from a tomographic image acquired by a medical apparatus such as an MRI apparatus or a CT apparatus, as shown in the example of FIG. 24, an operator selects representative points in the tomographic image. A device that designates and extracts a region based on the designated representative point is known.
[0008]
[Non-Patent Document 1]
Comprehensive information magazine for medicine and images Inner Vision (6 ・ 9) 2001 (pages 15-18)
[0009]
[Problems to be solved by the invention]
However, the bullseye display is not a direct representation of the shape of the heart, and there is a problem that it is difficult to understand intuitively.
[0010]
Furthermore, in the above bullseye display, the feature quantity of the tomographic image, such as the myocardial thickness, is represented by a concentric map, so the correspondence between the position on the map and the actual position on the heart is difficult to understand and is displayed on the map. It is difficult to grasp the feature quantity of tomographic images such as the myocardial thickness.
[0011]
For this reason, it is difficult for an observer to identify an abnormal part in a tomographic image such as a lesion part such as a myocardial infarction.
[0012]
In addition, in the conventional region extraction, the operator designates the representative point by himself, but such an operation is complicated for the operator, and the region extraction performed based on the representative point is quickly performed. It is difficult to do.
[0013]
An object of the present invention is to accurately extract a region such as a heart ventricle and a myocardium from a tomographic image to be observed, and to display an image reflecting the thickness of the myocardium based on each extracted region. It is an object of the present invention to provide an area extraction method, an area display method, and an image display device that can be used.
[0014]
Another object of the present invention is to provide an image display method and apparatus that allows an observer to quickly grasp the feature amount of an image and easily identify an abnormal portion in the image.
[0015]
Still another object of the present invention is to provide an area extraction method and apparatus for extracting an area without an operator specifying a representative point.
[0016]
[Means for Solving the Problems]
  In order to achieve the object, an image display device according to claim 1 is provided.Obtained for each of the plurality of tomographic images, means for obtaining a plurality of tomographic images with different slice positions of the observation object, means for obtaining a binarized image by thresholding each of the plurality of tomographic images, and A means for selecting a first region based on information indicating a shape from the binarized image, and a first region selected from the binarized image obtained for each of the plurality of tomographic images Means for obtaining a correlation and obtaining a common area over a range of a predetermined tomographic image, and determining a centroid of the common area obtained for each of the plurality of tomographic images, and limiting a predetermined area centered on the centroid Means for extracting a second region by threshold processing from within a predetermined region centered on the center of gravity of the common region obtained for each of the plurality of tomographic images;It is characterized by including.
[0017]
  In the binarized image, each region may be connected by blood vessels, noise, or the like. Therefore, it is preferable to provide a step of cutting the connected regions before the selection step.
[0018]
  The means for obtaining the first area obtains the AND condition of the area selected for each binarized image, and sets the area for obtaining the AND condition. Note that, in all binarized images, not only a region where the AND condition is satisfied, but a region where the AND condition is satisfied in most binarized images.
[0019]
  When the first area is obtained as described above, a predetermined area including the first area is limited. The predetermined region to be limited is, for example, a region within a predetermined radius according to the size of the observation target from the center of the first region, or a region larger than the first region by a predetermined thickness. . Then, a second area different from the first area is extracted from the predetermined area based on the shape and the like.
[0020]
  When the observation target is a heart, the first region corresponds to the ventricle, and the second region corresponds to the myocardium around the ventricle. Since the myocardium is around the ventricle, it is determined whether there is a pixel included in the myocardium (second region) around the pixel at the edge of the ventricle. When the ratio of determining that the myocardium is included around each pixel is greater than or equal to a certain size in the pixels of all the edges of the ventricle, the ventricle (first region) and the myocardium (second Are determined to be correctly extracted.
[0021]
  An image display device according to claim 2 is the image display device according to claim 1.,in frontThe outer peripheral image of the second region of the plurality of extracted tomographic images is projected onto a predetermined projection plane, and the direction of the transition length indicating the thickness of the second region is set as one of the shading parameters. A pseudo three-dimensional image shaded by a shading algorithm, or an equal thickness to show the thickness distribution of the second region on the projected image based on the transition length indicating the thickness of the second region lineThe tableShowFurther including image display meansIt is characterized by that.
[0022]
  That is, the direction of the transition length changes greatly in the portion where the thickness change of the first region is large, and this is reflected in the shading in the pseudo three-dimensional image.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, preferred embodiments of a region extraction method, a region display method, and an image display device according to the present invention will be described in detail with reference to the accompanying drawings.
[0040]
The region extraction method according to the present invention is based on a desired region (in this embodiment, the region A of the ventricle and This is a method of extracting the surrounding myocardial region B).
[0041]
FIG. 1 is a flowchart showing an embodiment of a region extraction method according to the present invention. [Step S10]
A plurality of tomographic images having different slice positions to be observed are subjected to threshold processing using a preset threshold value to obtain a plurality of binarized images. Only the boundary of the shadow of the tomographic image may be set to the high level “1”, and the others may be set to “0”.
[0042]
2, a0, b0,... N0 are a plurality of binarized images having different slice positions.
[Step S11]
In the binarized image, a plurality of regions may be connected due to a blood vessel portion, noise, or the like. In this case, the regions are cut.
[0043]
This cutting method will be described with reference to FIG.
[0044]
First, in FIG. 3A, the position of the center of gravity of the region 1 is obtained. The minimum length R in the region 1 while rotating the moving radius 2 in the direction of the arrow 3 around the center of gravity._minAsk for. This minimum length R_minA value obtained by multiplying by a constant is defined as a cutting length L. Based on this cutting length L, the blood vessel portion is cut as shown in FIG.
[0045]
That is, the determination areas 4 and 5 having the number of pixels corresponding to the cutting length L are set in the horizontal (X-axis) direction or the vertical (Y-axis) direction, and the areas 1, 1a and 1b (1a and 1b are blood vessel shadow areas) are set. Is determined to be smaller than the determination areas 4 and 5. In the case of the determination region 4 in the horizontal direction in FIG. 3B, the pixel value of the pixel x1 is “1” and the pixel value of the pixel xc is “0”. Instead, the pixels x1 to xc are left as they are.
[0046]
On the other hand, in the case of the determination region 5 in the vertical direction, since the pixel values of the pixel y1 and the pixel yc are both “0”, the determination region 5 is a cutting target, and the pixel values of the pixels y1 to yc are “0”. Converted. By performing the above processing while moving the determination areas 4 and 5, the blood vessel shadow areas 1 a and 1 b are cut, and only the area 1 remains.
[Step S12]
Since the ventricle is nearly circular compared to other organs, the region that appears to be a ventricle is selected using the shape.
[0047]
This sorting method will be described with reference to FIG.
[0048]
In FIG. 4A, a radius of a predetermined length is rotated by about 1 ° from an angle θ = 0 ° to θ = 360 ° around the center of the region 6 as a rotation center. At this time, the length at which the radius intersects the shadow at each angle is obtained. Let r be the minimum value of the obtained length. That is, the minor axis r of the region 6 is obtained. The area S of the region 6 is divided by the minor axis r. That is, S / r²Ask for. By comparing this value with a predetermined value, it is determined whether or not the region 6 is nearly circular. When the region 6 is circular, as shown in FIG. 4B, S / r²The value of π is π, and in the case of a square, as shown in FIG.²The value of is 4. In the case of a rectangle having an aspect ratio of 1: 2, as shown in FIG.²The value of is 8.
[0049]
Therefore, S / r of each region²For example, by selecting only those having a value of 8 or less, it is possible to select a region that seems to be a ventricle.
[0050]
In FIG. 2, a1, b1,... N1 indicate areas a1t1, a1t2, b1t1, b2t2, n1t1, n1t2, and n1t3 after selection.
[Step S13]
The correlation (AND) of the areas for each tomographic image selected as described above is obtained, and the common area is extracted. Note that the region extracted in this way is not limited to a region common to all tomographic images, but also includes a region common to a certain range of tomographic images.
[Step S14]
In each image, an area having no correlation with the extracted common area is deleted. As a result, only the ventricular region is extracted from each image.
[Step S15]
The center of gravity of the extracted common area is obtained, and an area having a constant radius r is defined around the center of gravity as shown in FIG. The constant radius r is a radius set in advance so that the observation target is included according to the size of the observation target.
[0051]
The limited region may be a region obtained by adding the thickness or margin of the myocardium to the outer periphery of the ventricle extracted in step S14.
[Step S16]
The tomographic image in the limited region is subjected to threshold processing with a preset threshold value, and a binarized image of the myocardium is extracted as shown in FIG.
[0052]
Next, a method for determining whether or not the ventricular region and the myocardial region extracted from each tomographic image as described above have been correctly extracted will be described.
[0053]
FIG. 6A shows the ventricle, and FIG. 6B shows the myocardium. Even if these are observed individually, it is not known whether the extraction of the ventricle and the myocardium was correct.
[0054]
As shown in FIG. 6B, anatomically, the myocardium is located around the ventricle. Therefore, it can be determined whether or not the extraction of the ventricle and the myocardium was correct by determining whether or not the myocardium is located around the ventricle.
[0055]
As shown in FIG. 6C, the total number of pixels on the edge that is considered to be the outer periphery (edge) of the region showing the ventricle is n, and the pixel i at the edge (1 ≦ i ≦ n) is the center, Let the right, bottom, and left pixels be a, b, c, d. Whether or not the pixel i is located at the edge of the ventricle can be determined by whether or not there are non-ventricular pixels in the pixels a to d around the pixel i. For example, in the case of the pixel i shown in FIG. 6C, since the surrounding pixels b and c are non-ventricular pixels, the pixel i is a pixel at the edge of the ventricle.
[0056]
In this way, if all the pixels (n) are considered to be ventricular edges, it is determined whether they are ventricular edge pixels, and the total number m (m ≦ n) of pixels determined to be ventricular edge pixels is determined. Ask.
[0057]
Similarly, whether or not the pixel i is in contact with the myocardium can be determined by whether or not the myocardial pixel is included in any of the pixels a to d around the pixel i. For example, in the case of the pixel i shown in FIG. 6C, since the surrounding pixels b and c are myocardial pixels, the pixel i is a pixel at the edge of the myocardium.
[0058]
In this way, if all the pixels (n) are considered to be ventricular edges, it is determined whether they are myocardial edge pixels, and the total number o (o ≦ n) of pixels determined to be myocardial edge pixels is determined. Ask.
[0059]
The ratio between the total number o of pixels determined as the myocardial edge pixels and the total number m of pixels determined as the ventricular edge pixels is equal to or greater than a certain value (for example, 90%) (o / m ≧ constant value). ), It is determined that the ventricular region and the myocardial region are correctly extracted.
[0060]
FIG. 7 is a flowchart showing a procedure for correctly extracting a ventricular region and a myocardial region.
[Step S50]
Parameters such as a threshold used for threshold processing in step S10 and step S16 shown in FIG. 1 are set.
[Step S51]
The ventricle and the myocardium are extracted from the tomogram according to the procedure shown in FIG.
[Step S52]
By the method described with reference to FIG. 6C, an extraction check is performed to determine whether the ventricular region and the myocardial region have been correctly extracted.
[Step S53]
If the ventricular region and the myocardial region are correctly extracted, the process ends. If not correctly extracted, the process proceeds to step 54.
[Step S54]
Change parameters such as the threshold and jump to step 51.
[0061]
Next, a display method for displaying an image of the heart from the image of the outer periphery of the myocardium extracted from each tomogram and the image of the outer periphery of the ventricle will be described.
[0062]
As shown in FIG. 8, the transition length indicating the heart wall thickness is obtained, and one end of the transition length is aligned with the reference line 50 (in FIG. 8, the outer periphery of the ventricle). The normal vector of each pixel point of the maximum transition line 51 (in FIG. 8, the outer periphery of the myocardium) constituted by the other end of the transition length is obtained, and the angle θ formed by this normal vector and the arbitrarily set projection plane 52 Ask for.
[0063]
Further, an angle η formed by a perpendicular line on which each pixel point is projected onto the projection plane 52 and a straight line perpendicular to the line representing the transition length is obtained. Then, the pixel value projected on the projection surface 52 of each pixel point on the outer periphery of the myocardium is added with a density proportional to the product of the power of cos θ and the power of cos η to obtain the pixel value on the projection surface 52. decide.
[0064]
Thereby, on the projection surface 52, for example, a pseudo three-dimensional image shaded as shown in FIG. 9 is displayed. In FIG. 9, 1 is the front of the projection plane and there is no change in the thickness of the myocardium, and 2 corresponds to the place where the myocardium is thin and the transition length is short.
[0065]
Here, the reference line to match the displacement length has been described according to the outer periphery of the ventricle, but since the size of the ventricle changes depending on the heartbeat, an arbitrary cylinder including the ventricle is obtained, and the reference line is aligned with the outer periphery. Also good. By aligning the reference line with the cylinder, it is not necessary to perform an operation for the alignment for each heartbeat, and the operability is improved. Further, the average, maximum, and minimum perimeters of all images used may be matched with the reference line. As a result, the matching operation can be performed for each reference value of the heart rate, so that the operability is also improved.
[0066]
FIG. 10 shows another display example. As shown in the figure, among the pixel points projected on the projection plane, pixel points (contour lines) corresponding to the outline of the heart are displayed, and the projection is performed based on the transition length indicating the thickness of the myocardium. A contour line is displayed in the outline of the heart to show the distribution of the thickness of the heart muscle. In FIG. 10, 3 indicates the thickest part of the myocardium, and 4 indicates the thinnest part of the myocardium.
[0067]
FIG. 11 shows a state in which a plurality of tomographic images are acquired at a predetermined time interval (for example, 80 milliseconds). For the plurality of tomographic images for each time phase of time phase 0, time phase 1,..., The above-described processing such as extraction of the ventricle and myocardium is performed, and the display as shown in FIG. Thus, it is possible to display a state in which the myocardium is exercising (particularly, a state in which the thickness of the myocardium changes). As a result, the infarcted part (the part where the thickness of the myocardium does not change) can be easily recognized.
[0068]
FIG. 12 is a schematic diagram showing a hardware configuration of an apparatus for carrying out the region extraction method and the region display method according to the present invention.
[0069]
This apparatus comprises a central processing unit (CPU) 10, a main memory 12, a magnetic disk 14, a display memory 16, a display 18, a controller 20, a mouse 22, a keyboard 24, and a common bus 26. This apparatus is a network. It is connected to the MR apparatus 30 via the (LAN) 28.
[0070]
The magnetic disk 14 stores each tomographic image of the subject acquired from the MR apparatus 30 via the network 28, and the CPU 10 performs predetermined processing according to the area extraction and area display software of the main memory 12. In this processing, input / output processing and processing operations using the mouse 22 and keyboard 24 attached to the controller 20 are performed. The processing result is displayed on the display 18 via the display memory 16, and the processing result and display contents are stored in the magnetic disk 14 and used for redisplay.
[0071]
Note that the tomographic image is not limited to that obtained from the MR apparatus 30, but may be obtained by another image diagnostic apparatus such as an X-ray CT apparatus or an ultrasonic diagnostic apparatus. Further, the observation target is not limited to the heart described in this embodiment.
(Second embodiment)
Hereinafter, preferred embodiments of an image display method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0072]
FIG. 13 shows an overall configuration of an image display system 70 to which the present exemplary embodiment is applied.
[0073]
The image display system 70 includes an image display device 72, a CT device 94, an MR device 96, and an image data server 98, which are connected via a network 92.
[0074]
The image display device 72 is an embodiment of the image display device according to the present invention, and the CT device 94 and the MR device 96 are devices that acquire images such as tomographic images. The image data server 98 stores and manages image data. The image display device 72, the CT device 94, the MR device 96, and the image data server 98 perform transmission / reception of image data via the network 92.
[0075]
Note that the image display device 72 can process an image such as a tomographic image taken under various conditions with respect to the type and part of the organ.
[0076]
In addition, various networks such as a LAN (local area network) and the Internet can be used as the network 92, and the image data server 98 can also use one or more servers connected to the network. it can.
[0077]
The image display device 72 includes a central processing unit (hereinafter referred to as a CPU) 76 that controls each component, and the CPU 76 is connected to a common bus 74. The common bus 74 stores a control program for the image display device 72 and a main memory 78 used as a storage area for image processing and data processing, and a magnetic disk storing image files, databases, programs, and the like. 80, a display memory 82 for temporarily storing display image data, a controller 86, and a keyboard 90 having keys and switches for setting various parameters are connected. The display memory 82 is connected with a display 84 (hereinafter referred to as CRT) for displaying images and the like, and the controller 86 is connected with a mouse 88 as means for performing various operations on the screen of the CRT 84. Yes.
[0078]
As the storage device, in addition to the magnetic disk 80, devices such as a CD-ROM drive, a magneto-optical disk (MO) drive, and a DVD drive can be connected, and a storage medium that can be inserted into and removed from these devices. An image file or the like may be input / output via the.
[0079]
Next, the operation of the above embodiment will be described. FIG. 14 shows a processing routine executed by the image display device 72.
[0080]
First, in step 200, a tomographic image file corresponding to a preset condition is read from the magnetic disk 80 via the mouse 88 and the keyboard 90.
[0081]
In addition to reading from the magnetic disk 80, the image file may be read from the image data server 98 via the network 92, or the image display device 72 may be provided with the storage device as described above and read via the storage medium. Good.
[0082]
In the next step 202, it is determined whether the criterion for extracting a tomographic image is a cardiac region cross-sectional area, a myocardial partial area, or a myocardial thickness average value. This determination is made by input via the mouse 88 or the keyboard 90. If the tomographic image extraction standard is the cardiac region cross-sectional area, the process proceeds to step 204. If it is the myocardial partial area, the process proceeds to step 212. If it is the myocardial thickness average value, the process proceeds to step 220.
[0083]
If the tomographic image extraction criterion is the heart area cross-sectional area, the cross-sectional area of the heart area is obtained for all tomographic images in step 204 and the next step 206, and then the process proceeds to step 208, where the cross-sectional area is maximum / minimum. A tomographic image is extracted.
[0084]
In the next step 210, the difference in myocardial thickness is calculated and stored for the tomographic image having the maximum / minimum cross-sectional area of the heart region. As shown in the example of FIG. 15, the calculated myocardial thickness difference is a difference in polar coordinate display angle measured in the radial direction from the center or center of gravity of the heart region or ventricle.
[0085]
On the other hand, if the tomographic image extraction criterion is the myocardial partial area in step 202, the process proceeds to step 212. In step 212 and step 214, the area of the myocardial portion is obtained for all tomographic images, and then the process proceeds to step 216 to extract the tomographic image having the maximum / minimum area.
[0086]
In the next step 218, as in step 210, the difference in myocardial thickness is calculated and stored for the tomographic image having the maximum / minimum myocardial partial area.
[0087]
If the tomographic image extraction standard is the myocardial thickness average value in step 202, the process proceeds to step 220. In steps 220 and 222, the myocardial thickness average value in each tomographic image is obtained for all tomographic images, and then the process proceeds to step 224 to extract a tomographic image having the maximum / minimum average value.
[0088]
In the next step 226, the myocardial thickness difference is calculated and stored for the tomographic image having the maximum / minimum myocardial thickness average value as in steps 210 and 218.
[0089]
When the myocardial thickness difference is calculated by any one of step 204 to step 210, step 212 to step 218, and step 220 to step 226, the process proceeds to step 228.
[0090]
In step 228, it is determined whether there is a threshold value for the difference in myocardial thickness. This determination can be made based on whether or not a threshold value is input via the mouse 88 or the keyboard 90. If the determination is affirmed, the process proceeds to step 230. If the determination is negative, the process proceeds to step 236.
[0091]
In addition to the difference in myocardial thickness, the threshold value can be set for a heart area cross-sectional area, a myocardial area, and the like.
[0092]
If the determination in step 228 is affirmative, an image enhancement range is set based on the threshold value in step 230. For example, a difference larger than the threshold value is set as the image enhancement range.
[0093]
In the next step 232, the difference in myocardial thickness is converted into a color. This process is a process of assigning a different color to the difference in the myocardial thickness calculated and stored in step 210, step 218, or step 226 according to the magnitude of the difference, and the image enhancement range set in step 230 above. Is considered. For example, red is assigned to a difference smaller than the threshold (outside the image enhancement range), blue is assigned to the largest difference, and a color gradation from red to blue is assigned to the difference (image enhancement range) therebetween.
[0094]
Thereafter, the process proceeds to step 234, and the color assigned in step 232 is added to the corresponding myocardial portion for each tomographic image input in step 200.
[0095]
On the other hand, if the determination in step 228 is negative, the process proceeds to step 236, and the myocardial thickness difference is converted into a color in the same way as in step 232. For example, red is assigned to the smallest difference in myocardial thickness, blue is assigned to the largest difference, and color gradations from red to blue are assigned to the difference in myocardial thickness therebetween.
[0096]
Thereafter, the process proceeds to step 238, and the color assigned in step 236 is added to the corresponding myocardial portion for each tomographic image input in step 200.
[0097]
In step 240, the image colored in step 234 or step 238 is displayed. In this display, a tomographic image at an arbitrary time phase is selectively displayed as a still image as shown in the example of FIG. 16, or may be displayed in order of time as a moving image as shown in the example of FIG. As shown in the example of FIG. 18, an image colored in consideration of the image enhancement range set based on the threshold value may be displayed.
[0098]
In the flowchart shown in FIG. 2 and the above description, a case where a threshold value is set and a tomographic image is colored based on the threshold value is described. As shown, after displaying an image, a threshold value may be set again, and an image colored based on the threshold value may be displayed.
[0099]
When displaying, as shown in the examples of FIGS. 16, 17 and 18, the correspondence between the difference in myocardial thickness and the color gradation, the number of the time phase direction of the image to be displayed, and the set threshold value Values etc. can be displayed along with images.
[0100]
Furthermore, start / end of image display, setting of threshold, selection and switching of still image or moving image display, selection of time phase of image to be displayed, setting of display speed in case of moving image display, etc. The operator of the device 72 can freely and repeatedly perform the operation by operating buttons, scroll bars, and the like displayed on the screen of the CRT 84 via the mouse 88 and the keyboard 90.
[0101]
When the display of the image is finished in step 240, the process proceeds to step 242.
[0102]
In step 242, it is determined whether or not to end the process. If the determination is affirmative, the present processing routine is terminated, and if the determination is negative, the processing returns to step 200.
[0103]
As described above, in the image display system 70 to which the present exemplary embodiment is applied, the tomographic image input to the image display device 72 is displayed by being colored according to the magnitude of the difference in myocardial thickness. An observer can quickly and easily identify a lesion portion in a tomographic image such as myocardial infarction (the infarcted site has a small change in myocardial thickness and a small difference).
[0104]
Furthermore, in the image display system 70 to which the present exemplary embodiment is applied, it is possible to perform functional observation of the heart by reproducing a moving image in a state in which image enhancement processing is performed, that is, in a state in which a lesion is identifiable. .
[0105]
In this embodiment, the case where a tomographic image colored as an image display is displayed has been described. However, the display of an image is not limited to a tomographic image, and volume rendering or surface as shown in the example of FIG. It may be a three-dimensional image created and colored using a technique such as rendering. In addition, the three-dimensional image created in this way may be displayed as an image at an arbitrary time phase as a still image or as a moving image in order of time phase.
[0106]
Further, in the present embodiment, a case has been described in which image processing is assigned a color gradation from red to blue according to the difference in myocardial thickness, but image enhancement processing is not limited to this, You may make it allocate light and shade according to the magnitude | size of a difference.
(Third embodiment)
Hereinafter, preferred embodiments of a region extraction method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
[0107]
FIG. 20 shows the overall configuration of a region extraction system 40 to which this exemplary embodiment is applied.
[0108]
The region extraction system 40 includes a region extraction device 42, a CT device 64, an MR device 66, and an image data server 68, which are connected via a network 62.
[0109]
The region extraction device 42 is an embodiment of the region extraction device according to the present invention, and the CT device 64 and the MR device 66 are devices that acquire images such as tomographic images. The image data server 68 is for accumulating and managing image data. The region extraction device 42, the CT device 64, the MR device 66, and the image data server 68 perform image data transmission / reception via the network 62.
[0110]
Note that the region extraction device 42 can process images such as tomographic images taken under various conditions for organ types, parts, and the like.
[0111]
Further, various networks such as a LAN (local area network) and the Internet can be used as the network 62. As the image data server 68, one or more servers connected to the network can be used. it can.
[0112]
The area extraction device 42 includes a central processing unit (hereinafter referred to as CPU) 46 that controls each component, and the CPU 46 is connected to a common bus 44. The common bus 44 stores a control program for the area extraction device 42 and a main memory 48 used as a storage area for image processing and data processing, and a magnetic disk storing image files, databases, programs, and the like. 50, a display memory 52 for temporarily storing image data for display, a controller 56, and a keyboard 60 having keys and switches for setting various parameters. The display memory 52 is connected to a display for displaying images (hereinafter referred to as CRT) 54, and the controller 56 is connected to a mouse 58 as means for performing various operations on the screen of the CRT 54. Yes.
[0113]
As the storage device, in addition to the magnetic disk 50, devices such as a CD-ROM drive, a magneto-optical disk (MO) drive, and a DVD drive can be connected, and a storage medium that can be inserted into and removed from these devices. An image file or the like may be input / output via the.
[0114]
Next, the operation of the above embodiment will be described. FIG. 21 shows a processing routine executed by the region extraction device 42.
[0115]
First, in step 100, a tomographic image file corresponding to a preset condition is read from the magnetic disk 50 via the mouse 58 and the keyboard 60.
[0116]
In addition to reading from the magnetic disk 50, the image file may be read from the image data server 68 via the network 62, or the image display device 42 may be provided with a storage device as described above and read via a storage medium. Good.
[0117]
In the next step 102, it is determined whether or not the designation of the representative point is automatic. This determination can be made by the screen display of the CRT 54 and input via the mouse 58 or the keyboard 60 as shown in the example of FIG. If the determination is affirmed, the representative point is automatically extracted in the steps after step 104, and if the determination is negative, the representative point is set by the operator's designation in the steps after step 118.
[0118]
If the determination in step 102 is affirmative, the process proceeds to step 104 to clear the addition memory (the storage area used for adding difference data in the main memory 48), and then proceeds to step 106.
[0119]
In step 106, a reference image is set. The reference image may be a tomographic image in an arbitrary time phase among the input tomographic images, for example, a tomographic image in the first time phase.
[0120]
In the next step 108, for the tomographic image having a time phase different from that of the reference image among the input tomographic images, the difference between the image data is calculated for each pixel, and an absolute value is obtained.
[0121]
In the next step 110, the absolute value of the difference obtained in step 108 is added to the addition memory, and then the process proceeds to step 112.
[0122]
The above-described processing of Step 108 and Step 110 is performed for all tomographic images having a time phase different from that of the reference image.
[0123]
Here, when the input is a tomographic image of the heart, the size of the heart is displaced (deformed) with time, but the portion other than the ventricle is basically slightly displaced. For example, as shown in the example of FIG. 23, the portions 1, 2, 5, and 6 hardly change, the ventricle 3 and the myocardium 4 change, and particularly the ventricle 3 changes greatly. Therefore, when the difference is calculated between the tomographic images having different time phases and added, only the pixel value of the ventricle portion having a large displacement becomes a large value.
[0124]
In step 112, it is determined whether or not processing has been completed for all tomographic images. If the determination is affirmative, the process proceeds to step 114. If the determination is negative, the process returns to step 108.
[0125]
In step 114, threshold processing is performed on the addition memory to obtain a binary image of 0 and 1, and then the process proceeds to step 116 where the target region (for example, the region of pixel value 1) of the binary image is processed. Find the center of gravity.
[0126]
In the next step 118, the center of gravity obtained in step 116 is set as a representative point.
[0127]
In this way, in the region extraction system 40 to which this embodiment is applied, the representative point can be automatically set based on the input tomographic image without the operator specifying the representative point.
[0128]
On the other hand, if the determination in step 102 is negative, a representative point is set based on the operator's designation through the processing from step 120 to step 124.
[0129]
In step 120, a reference image is set. As in step 106, the reference image can be a tomographic image at an arbitrary time phase as the reference image.
[0130]
In the next step 122, representative points are set. This process is a process of setting a point in the reference image designated by the operator via the mouse 58 or the keyboard 60 as a representative point, as shown in the example of FIG.
[0131]
As described above, in the region extraction system 40 to which the present exemplary embodiment is applied, it is also possible to set a representative point according to an operator's designation.
[0132]
When the representative point is set by the processing of step 118 or step 122, the process proceeds to step 124, and region extraction is performed based on the representative point. This region extraction process can be performed by a method similar to the conventional method. When region extraction ends, the process proceeds to step 126.
[0133]
In step 126, an image is displayed. In this image display, the input tomographic image, the representative points set automatically or by the operator's designation, and the extracted area can be displayed. These displays can be freely repeated as the operator operates the mouse 58 or the keyboard 60. Further, the tomographic image or the like may be subjected to processing such as coloring or shading, or an image obtained by superimposing the tomographic image, the representative point, and the extracted region may be displayed. When the image display ends, the process proceeds to step 128.
[0134]
In step 128, it is determined whether or not to end the process. If the determination is affirmative, the present processing routine is terminated, and if the determination is negative, the processing returns to step 100.
[0135]
As described above, in the region extraction system 40 to which the present embodiment is applied, the representative points can be automatically set without specifying the operator himself, and the region extraction can be performed quickly. One is free from annoyance.
[0136]
Further, in the region extraction system 40 to which the present embodiment is applied, the input tomographic image, the representative point, and the extracted region are displayed, so that the operator can confirm the processing result quickly and easily. .
[0137]
【The invention's effect】
As described above, according to the present invention, it is possible to accurately extract regions such as the heart ventricle and the myocardium from the tomographic image to be observed, and reflect the thickness of the myocardium based on the extracted regions. It is possible to display an intuitively easy-to-understand image. Therefore, the heart can contribute to the diagnosis of functional disorders such as myocardial infarction.
[0138]
Further, according to the present invention, the observer can quickly grasp the feature amount of the image, and can easily identify the abnormal part in the image.
[0139]
Furthermore, according to the present invention, the region can be extracted without the operator specifying the representative point.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of a region extraction method according to the present invention.
FIG. 2 is a diagram used for explaining a region extraction method according to the present invention.
FIG. 3 is a diagram used for explaining a cutting method when a plurality of regions are connected.
FIG. 4 is a diagram used for explaining a method of selecting an area by shape.
FIG. 5 is a diagram used for explaining a region extraction method according to the present invention.
FIG. 6 is a diagram used for explaining a method of determining whether or not a plurality of extracted areas are correct.
FIG. 7 is a flowchart showing a procedure until a correct area is extracted.
FIG. 8 is a diagram used for explaining a region display method according to the present invention.
FIG. 9 is a diagram showing an example of an image displayed based on the region display method according to the present invention.
FIG. 10 is a diagram showing another example of an image displayed based on the region display method according to the present invention.
FIG. 11 is a diagram illustrating a state in which a plurality of tomographic images are captured at predetermined time intervals.
FIG. 12 is a diagram illustrating a hardware configuration example of an apparatus to which the region extraction method and the region display method according to the present invention are applied.
FIG. 13 is a configuration diagram of an image display system according to an embodiment of the present invention.
FIG. 14 is a flowchart showing processing in the image display apparatus according to the embodiment of the present invention.
FIG. 15 is a conceptual diagram showing calculation of a difference in myocardial thickness between tomographic images according to one embodiment of the present invention.
FIG. 16 is a diagram illustrating an example of displaying a tomographic image as a still image according to an embodiment of the present invention.
FIG. 17 is a diagram illustrating an image when a tomographic image is displayed as a moving image according to the embodiment of the present invention.
FIG. 18 is a diagram illustrating an example of display of an image colored in consideration of an image enhancement range set based on a threshold according to an embodiment of the present invention.
FIG. 19 is a diagram showing an example of display of a three-dimensional image according to one embodiment of the present invention.
FIG. 20 is a configuration diagram of a region extraction system according to an embodiment of the present invention.
FIG. 21 is a flowchart showing processing in the region extraction device according to one embodiment of the present invention.
FIG. 22 is an image diagram showing an example of a representative point setting method selection screen.
FIG. 23 is an image diagram showing an example of a temporal change in the size of the heart.
FIG. 24 is an image diagram showing an example of representative point setting by an operator's designation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Central processing unit (CPU), 12 ... Main memory, 14 ... Magnetic disk, 16 ... Display memory, 18 ... Display, 20 ... Controller, 22 ... Mouse, 24 ... Keyboard, 26 ... Common bus, 28 ... Network, 30 ... MR device, 40 ... region extraction system, 42 ... region extraction device, 70 ... image display system, 72 ... image display device

Claims (2)

Means for acquiring a plurality of tomographic images having different slice positions of the observation target;
Means for thresholding each of the plurality of tomographic images to obtain a binarized image;
Means for selecting a first region based on information indicating a shape from a binarized image obtained for each of the plurality of tomographic images;
Means for obtaining a correlation between first regions selected from the binarized images obtained for each of the plurality of tomographic images, and obtaining a common region over a range of a predetermined tomographic image;
Means for determining a center of gravity of a common area obtained for each of the plurality of tomographic images, and limiting a predetermined area centered on the center of gravity;
Means for extracting a second region by threshold processing from a predetermined region centered on the center of gravity of the common region obtained for each of the plurality of tomographic images;
An image display device comprising: The outer peripheral image of the second region of the plurality of tomographic images that have been pre-Symbol extraction, as well as projected onto the predetermined projection surface, one of the displacement length direction of the shading parameters indicating the thickness of the second region In order to show the thickness distribution of the second region on the projected image based on the pseudo three-dimensional image shaded by the shading algorithm, or on the transition length indicating the thickness of the second region, etc. the Atsusen further comprising a table Shimesuru image display means,
The image display apparatus according to claim 1.

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