JP2005073817A - Medical image displaying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a medical image displaying apparatus which is capable of setting one region accurately by a region growing method regardless of an image with an indistinct region boundary. <P>SOLUTION: The apparatus is equipped with an input device 21, which displays images acquired by a medical image diagnostic apparatus on a display device 23 and sets at least a starting point for extracting a desired internal organ region on the displayed image, a control device 20 which extracts a pixel in the proximity of the set starting point if the pixel is within a prescribed threshold value when compared with a pixel value at the origin, clearly indicates the internal organ region by superposing the periphery of the extracted internal organ region on the image on the display device 23, varies the threshold value for adjusting the clearly indicated internal organ region within a proper range by the input device 21, and controls to interlock the size of the periphery of the clearly indicated internal organ region based on the varied threshold value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an area display method and an image display method, and relates to an area display apparatus and an image display apparatus that display organs extracted from medical images such as MR, CT, and ultrasound.

When extracting a lesion site such as an organ or a tumor or a cyst on a medical image and measuring its shape and size, for example, the region expansion method described in [Patent Document 1] has been used.
Japanese Patent No. 2859995

  However, in the above background art, for example, when the threshold setting is not accurate when there is an image in which the boundary of the region is unclear, such as an ultrasound image, or when there are a plurality of regions close to pixel values, There is a problem in that it is not uncommon for a region to be recognized as one region.

  An object of the present invention is to provide a medical image display device capable of accurately setting a desired region by a region expansion method even if the region boundary is unclear.

In order to solve the above-described problems, the present invention is configured as follows.
(1) Means for displaying an image obtained by the medical image diagnostic apparatus on a display device, setting at least one start point for extracting a desired organ region in the displayed image, and the set start point In a medical image display device comprising means for extracting a neighboring pixel as the organ region if it is within a predetermined threshold range compared with the pixel value of the starting point, the periphery of the extracted organ region is defined as the image. Means for clearly displaying the organ region by overlapping the display on the display device, means for varying the threshold for adjusting the manifested organ region to an appropriate range, and a threshold variable by the threshold variable means. And a means for controlling the surrounding size of the organ region specified by the specifying means to be interlocked.
As a result, even if the image has an unclear region boundary, a desired region can be accurately set by the region expansion method.

(2) Preferably, in (1), the means for measuring the measured amount including the area of the organ region, the length of the major axis, the length of the minor axis, and the perimeter length varied by the threshold value varying means, and the display device Displays the measured quantity on the measuring means.
As a result, the size of the organ region can be measured in real time.

(3) More preferably, in (1), the means for calculating at least one area displacement of each area difference or area ratio in different organ regions varied by the threshold value varying means, and the control means, Based on the area displacement calculated by the area displacement calculating means, control is performed so that the size of the periphery of the organ region specified in the explicit means is interlocked.
As a result, it is possible to provide information that allows the operator to determine whether or not the organ region is properly extracted due to the area displacement of the organ region.

(4) Further, in a medical image display device provided with means for displaying an image obtained by a medical image diagnostic device including an ultrasonic diagnostic device on a display device and extracting a desired organ region from the displayed image, Means for displaying the periphery of the extracted organ region in a superimposed manner on the image and the display device to clearly indicate the organ region, and means for varying the threshold value for adjusting the specified organ region to an appropriate range And a means for controlling the surrounding size of the organ region specified in the explicit means based on the threshold variable by the threshold variable means to obtain the surrounding of the organ region by interpolation. Features.
As a result, the organ region in the ultrasonic image can be clearly displayed.

  According to the present invention, it is possible to provide a medical image display apparatus that can accurately set one area by an area expansion method even if the area boundary is unclear.

  Embodiments of the present invention will be described with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the invention, and the repetitive description thereof is omitted.

  FIG. 1 is a diagram showing a system configuration example of a medical image display apparatus of the present invention, FIG. 2 is a block diagram excerpting functions of main parts of FIG. 1, and FIG. 3 is a block diagram showing details of a control unit in FIG. . These system configuration diagrams and block diagrams are common to all the embodiments described later.

  The system configuration including the medical image display device of the present invention includes a CPU 10 that performs image processing calculation, a main memory 11 that stores calculation progress, and a magnetic that stores images obtained by the medical image device 12 such as CT, MRI, and ultrasound. A disk 13, a keyboard 14 as an input device, a mouse 16 connected to a controller 15, a display memory 17 for displaying calculation results, a display 18 such as a CRT, and a LAN 19 connecting them.

  As shown in FIG. 2, in the medical image display device, a control device 20 is connected to an input device 21, a storage device 22, and a display 23, respectively. Of course, transmission / reception of medical image data from a network connected to the control device 20 is also included in the present invention.

  The control device 20 controls information input from the input device 21 or the storage device 22 and outputs the information to the display device 23 or stores the information output to the display device 23 by the storage device 22. The input device 21 is a keyboard, a pointing device such as a mouse or a drag ball, and is used by an operator to perform settings and operations for performing image processing based on display information on the display unit 23. The display 23 is a CRT or a liquid crystal display for displaying image information, parameter information for performing image processing, and the like.

  As shown in FIG. 3, the control device 20 includes an input image display image creation unit 30 connected to the input device 21 and the storage device 22, a region expansion parameter setting unit 31 connected to the input device 21, and a region expansion A processing unit 32 and a result image creation unit 33 are included.

  Next, the operation in each embodiment will be described with reference to the drawings. FIG. 4 is a diagram showing an example of a user interface common to the embodiments described below.

(First embodiment)
FIG. 5 is a flowchart for explaining the first embodiment, and FIG. 6 is a schematic diagram for explaining step 52 of FIG.
The operator operates the input device 21 and presses the image input button 40 to input the medical tomographic image read from the storage device 22 to the control unit 20. (Step 50)

  The control unit 20 displays the input medical tomographic image on the display 23 (medical image display unit 41 on the user interface). (Step 51)

  The operator operates the input device 21 to set a region of interest for performing region expansion processing. This setting of the region of interest can be omitted when the entire image is targeted, for example. The region of interest may be a region displayed as a rectangle 61 on the image 60 as shown in FIG. 6, or may be a region displayed as an ellipse 62. The size and direction (angle) of these regions of interest can be arbitrarily changed by the operator. Instead of setting the region of interest as a rectangle or an ellipse, only the region surrounded by the thick solid line 63 is displayed on the display 23 in advance, and the region inside the thick solid line region may be used as the region of interest. The operator can operate the input device 21 to change the region of interest, for example, by sliding the image 64 indicated by the solid line to the position of the image 65 indicated by the broken line. In addition, the size of the region of interest indicated by the thick solid line can be arbitrarily changed by the operator. The region-of-interest setting process can be omitted. In that case, the entire input image is set as the region of interest. (Step 52)

  The operator operates the input device 21 to designate one point in the organ region of interest on the medical image displayed on the medical image display unit 41. The point specified here is the starting point of the area expansion process described below. The designated point is displayed as a circle 42 on the medical image display unit 41. If the operator accidentally specifies a point that is not intended, the circle 42 moves to the newly specified point by operating the input device 21 and specifying another point again. The point is adopted as the starting point of the area expansion process. The coordinates and pixel value of the pixel of the designated point 42 may be displayed on the image information display unit 43. Instead of manually setting the region expansion start point, the point that takes the maximum pixel value or the minimum pixel value in the set region of interest may be set as the region expansion start point. Alternatively, the center point of the region of interest may be set as the region expansion start point. (Step 53)

The operator operates the input device 21 to move the scroll bar 44 on the display unit 23, and sets a threshold width for an area expansion process to be described later. The set threshold value is displayed on the threshold value display unit 45. The threshold width is a parameter for determining a threshold value for an area expansion process described later.
Here, the threshold value width may be set by directly inputting a numerical value into the threshold value width display unit 45. (Step 54)

  The control unit 20 performs region expansion processing using the set region expansion processing start point 42 and the threshold value displayed on the threshold value display unit 45. In the area expansion process, first, a threshold value is set. For example, the threshold value is given as “3 ± 47” using the pixel value “3” of the region expansion processing start point displayed on the image information display unit 43 and the threshold width “47” displayed on the threshold width display unit 45. It is done. That is, the lower threshold is “−44” and the upper threshold is “50”. The control unit 20 examines the pixels around the region expansion start point 42 and connects regions having pixel values within the threshold range. Finally, a connected region including the region expansion start point 42 and having a pixel value within the threshold range is obtained. (Step 55)

In setting the threshold value, instead of setting one type of threshold width as in the above setting method, prepare two types of threshold width, upper threshold width and lower threshold width, and add and subtract to the pixel value of the region expansion start point respectively. The threshold value may be obtained. In this case, two types of scroll bars, an upper threshold width setting scroll bar and a lower threshold width setting scroll bar, are arranged on the user interface.
The control unit 20 assigns an arbitrary color (pixel value) to all the pixels in the connection area. Here, the arbitrary color may be selectable by the operator, or a preset color may be used. (Step 56)

  The control unit 20 displays on the image display unit 46 an image in which colors are assigned to the pixels in the connection area. The hatched area 47 is a connected area obtained by the area expansion process. Of course, an image assigned a color to the connected area may be displayed on the image display unit 41 as it is instead of being displayed on the image display unit 46. (Step 57)

  The operator looks at the result image and determines whether to reset the threshold width. If the obtained region is clearly wrong, the threshold width is reset and the process proceeds to step 55. If the obtained area is appropriate, the operator proceeds to step 59 without performing input. When the operator operates the scroll bar 44 or changes the value in the threshold width display unit 45 while the colored image in the connected region is displayed on the image display unit 46, the region is displayed in real time on the image display unit 46. An extended processing result image can be displayed. The operator can obtain an appropriate boundary of the region by resetting the threshold width while visually confirming. For example, as illustrated in FIG. 7, when the scroll bar 70 is operated and the threshold width is set to a small value “23” displayed on the threshold width display unit 71, the obtained extraction region is the extraction region displayed on the image display unit 72. As shown in 73, it is smaller than the actual area. On the other hand, when the scroll bar 70 is operated and the threshold width is set to a large value “96” displayed on the threshold width display section 71, the obtained extraction area 74 extends to an area other than the area to be extracted. In these cases, the operator interactively extracts a region by resetting the threshold width. (Step 58)

  The control unit 20 stores the coordinates of the organ region obtained by the region expansion process in the main memory. The stored coordinates are used when measuring the area of the organ area, the length of the long axis, the length of the short axis, the circumference, and the like. (Step 59)

(Second embodiment)
FIG. 8 is a flowchart for explaining the second embodiment.
The operator operates the input device 21 and presses the image input button 40 to input the medical tomographic image read from the storage device 22 to the control unit 20. (Step 800)

  The control unit 20 displays the input medical tomographic image on the display 23 (medical image display unit 41 on the user interface). (Step 801)

  The region of interest is set in the same manner as in step 52 of the first embodiment. (Step 802)

  The operator sets the region expansion start point manually or automatically by the same method as in step 53 of the first embodiment. (Step 803)

  The operator operates the input device 21 to operate the scroll bar 44 or sets the initial threshold width by directly inputting a numerical value to the threshold width display unit 45. Here, the initial threshold width is set to “1”, for example. The threshold width changes in the second embodiment as will be described later. What is set here is a value serving as a reference for the change. (Step 804)

  The control unit 20 performs region expansion processing based on the set region expansion start point and threshold width. (Step 805)

The control unit 20 obtains the area of the connected region or the number of pixels in the region (= S ₀ ) obtained by the region expansion process. May be displayed area value S ₀ obtained here to the image information display section 43. (Step 806)

  The control unit 20 changes the set threshold width. For example, the threshold width may be changed by adding 1 to the set threshold width. (Step 807)

  The control unit 20 performs region expansion processing using the region expansion start point set in step 803 and the threshold width set in step 807. (Step 808)

The control unit 20 obtains the area of the connected region obtained in Step 808 or the number of pixels in the region (= S ₁ ). The area value obtained here may be displayed on the image information display unit 43. (Step 809)

The control unit 20 obtains a difference (= S ₁ −S ₀ ) between the area values S ₀ and S ₁ . If the difference obtained here exceeds a predetermined threshold value set in advance, it is considered that the area change is large, and the process proceeds to Step 811. On the other hand, if the difference does not exceed a certain threshold, it is considered that the area change is small, and the process returns to step 807. Here, the value of S ₁ is substituted for the area value S _0, and the same operation is repeated from step 807 to step 810 until the area change becomes large. Here, an area ratio (= S ₁ / S ₀ ) may be used instead of the area difference. (Step 810)

Here, the processing in step 810 will be described with reference to FIG. Consider a case where regions 91 and 92 with close pixel values exist in the medical image 90. A point 93 in the region 91 is set as a region expansion start point. The area 94 has a very large pixel value or a small pixel value as compared with the areas 91 and 92. By gradually increasing the threshold width, the threshold range is expanded. When the threshold width becomes larger than a certain width, the areas 91 and 92 are connected to form one area by the area expansion process (area 95). In the threshold width immediately before the regions 91 and 92 are connected, the region 91 is the only region obtained by the region expansion process. Therefore, when the threshold width is gradually changed, there is a place where the area of the obtained connection region changes rapidly. If the immediately preceding threshold width is used, only the region 91 can be extracted without underestimating.
The control unit 20 performs any colored coupling in the region corresponding to the area value S _0. Here, the arbitrary color may be selectable by the operator, or a preset color may be used. (Step 811)

  The control unit 20 displays on the image display unit 46 an image in which colors are assigned to the pixels in the connection area. The hatched area 47 is a connected area obtained by the area expansion process. Of course, an image assigned a color to the connected area may be displayed on the image display unit 41 as it is instead of being displayed on the image display unit 46. (Step 812)

(Third embodiment)
In the first and second embodiments, the start point of area expansion is set to only one point. However, in the third embodiment, a plurality of area expansion start points can be set. The operator may manually set a plurality of area expansion start points using the input device 21. A plurality of points having the minimum pixel value or the maximum pixel value may be used as the region expansion start point. Alternatively, all pixels having a pixel value smaller than a preset threshold value, or all pixels having a pixel value larger than a preset threshold value may be used as the region expansion start point. In this case, there may be a plurality of connected regions obtained by the region expansion process. When there are a plurality of extracted connected regions, only the region of interest is selected.

  Alternatively, different threshold values may be set for a plurality of start points, and the area expansion may be performed independently. The region obtained for each start point and threshold value may be displayed in different colors. Thereby, it is possible to simultaneously extract a plurality of organs, a plurality of tumors, and the like.

  In addition, the threshold setting performed by the operator for a plurality of start points may be one type. However, in the region extraction means that is performed for each region selected by the operator for region extraction, the one type of value set as the threshold may be weighted for each of the plurality of regions. . For example, consider a case where “1” is selected in the initial threshold width setting described in step 804. Here, although there are a plurality of desired region extraction locations, the threshold value change described in steps 804 to 811 is limited to only one type.

  Consider a case where there are three independent extraction desired regions at the same time. For the first extraction region, the initial threshold setting width of “1” is applied as it is by the region extraction means. For the second extraction area, for example, “3” is applied as the initial threshold setting width, and “5” is set for the third extraction area. Although it is a type, the area extraction may be performed by automatically assigning a weight determined to be optimal to each desired extraction area in the actual calculation.

In this weighting method, for example, for each area to be extracted, the luminance distribution is examined for an area having an appropriate width. For an area where the change is large, a large weight is assigned to an area where the change in the luminance distribution is small. On the other hand, it is conceivable that weighting is not performed or small weighting is performed.
The attention area selection process may be performed manually by an operator. Alternatively, a region near the center of a region of interest that is set in advance may be adopted as the region of interest. Or you may employ | adopt as an attention area | region the area | region with the largest area value among the several area | regions obtained.

  The four embodiments have been described above. Only one of these embodiments may be implemented in a system including a user interface, or all the embodiments may be made in advance, and an operator operates the input device 21 to select a mode selection radio. Any mode from group 58 may be selected and used.

  In addition to the area value of the area obtained by area expansion, the long axis and short axis length of the rectangle surrounding the area, the average pixel value, the maximum pixel value, and the minimum pixel value in the area are calculated to display image information. It may be displayed on part 43. Of course, other measurement values may be displayed.

(Fourth embodiment)
Here, an ultrasonic diagnostic apparatus will be described as a specific example of the medical image display apparatus.
As shown in FIG. 10, the ultrasonic diagnostic apparatus transmits an ultrasonic wave to a subject (not shown) and receives a reflected echo signal from the subject, and drives the probe 100 A transmission / reception unit 101 that performs signal processing such as amplification of the reflected echo signal, a phasing unit 102 that phasing the signal-processed reflected echo signal, and a monitor of the phased signal A digital scan converter unit (DSC) 103 that performs scan conversion to the scanning line, a monitor 104 that displays the scan-converted signal, and image data extraction that sets a region of interest (ROI) in the image displayed on the monitor 104 Unit 105, region extraction calculation unit 106 for extracting an organ region in the set ROI, transmission / reception unit 101, phasing unit 102, DSC 103, image data extraction unit 105, and region extraction calculation unit 106 are controlled. Various control information in the control unit 107 and the control unit 107 And an operation section 108 which is input by the operator.

  The operator designates the start point 112 of the region expansion process in the arbitrary region extraction part with the indicator such as the pointer shown in FIG. 11 for the diagnostic images 110 and 111 obtained by the ultrasonic diagnostic apparatus. The shape and contour of the part can be automatically extracted.

  For regions where the boundary of the region is unclear, the operator can specify the ROI123 as shown in Fig. 12 to limit the extraction region, and the operator can arbitrarily select the obtained extraction unit By performing interpolation suitable for a certain part, it is possible to compensate for a part with an unclear boundary, or to draw a contour for obtaining information more easily than an extracted selected part.

  The region rendering algorithm uses an arbitrary region extraction means such as a snake method or a region growing method to grasp a rough outline shape of the measurement object. Furthermore, an interpolation algorithm that takes into account the general shape of the organ is used for the obtained contour to compensate for an obscure portion in the ultrasonic diagnostic apparatus, and information is provided to the apparatus user.

    In addition, various information (diameter, radius, etc.) is automatically measured from the obtained part and information is provided at the same time.

  The diagnostic image used for the extraction process is not limited to the image obtained in the normal mode # by the apparatus, but may be an image subjected to image processing that can be arbitrarily selected by the user, such as differential calculation.

  Furthermore, the image subjected to this image processing may be displayed on a monitor, and the above extraction processing may be performed based on the display.

  Further, according to each of the embodiments described above, it is possible to manually or automatically extract a region of interest such as an organ, a tumor, or a cyst from a medical image. By making the threshold variable or setting the region of interest, it is possible to prevent a plurality of regions from being connected and extracted. Furthermore, it is possible to easily measure the amount of the extracted area, the length of the major axis / minor axis of the figure surrounding the extracted area, the average pixel value, and the like. In an ultrasonic image or the like, the boundary between regions is often ambiguous, but the present invention can quantitatively determine the boundary.

  Furthermore, by applying this method to an arbitrary plurality of areas selected by the user of the apparatus, the boundaries of the extracted plurality of areas can be drawn simultaneously.

The figure which shows the system configuration example of the medical image display apparatus of this invention. The block diagram which extracted the function of the principal part of FIG. FIG. 3 is a block diagram showing details of a control unit in FIG. The figure which shows the example of the user interface common to each embodiment. 6 is a flowchart for explaining the first embodiment. FIG. 6 is a schematic diagram illustrating step 52 in FIG. FIG. 6 is a schematic diagram illustrating step 58 in FIG. 9 is a flowchart for explaining a second embodiment. FIG. 9 is a schematic diagram illustrating step 810 in FIG. The figure which shows the structural example of an ultrasound diagnosing device. The figure which shows the aspect which sets a starting point to an ultrasonic image. The figure which shows the transition of a display when an ultrasonic image is used.

Explanation of symbols

  20 ... Control device, 21 ... Input device, 23 ... Display

Claims (4)

Means for displaying an image obtained by the medical image diagnostic apparatus on a display device, setting at least one start point for extracting a desired organ region in the displayed image, and pixels adjacent to the set start point And a means for extracting the organ region as long as it is within a predetermined threshold range compared to the pixel value of the starting point, wherein the image and the display device surround the extracted organ region. Means for clearly displaying the organ region by overlapping the display, means for changing the threshold for adjusting the specified organ region to an appropriate range, and the explicit based on the threshold variable by the threshold variable unit A medical image display device comprising: means for controlling the surrounding size of the organ region clearly indicated by the means to be interlocked with each other. Means for measuring a measurement amount including an area of an organ region, a length of a short axis, a length of a short axis, and a perimeter, which are varied by the threshold variable means; and the display device displays the measurement amount measured on the measurement means. The medical image display apparatus according to claim 1. Means for calculating an area displacement of at least one of an area difference or an area ratio in different organ regions varied by the threshold value varying means; and the control means is based on the area displacement calculated by the area displacement calculating means. 2. The medical image display apparatus according to claim 1, wherein control is performed so that the peripheral size of the organ region clearly shown in FIG. In the medical image display device provided with means for displaying an image obtained by a medical image diagnostic device including an ultrasonic diagnostic device on a display device and extracting a desired organ region from the displayed image, the extracted organ Means for displaying the surroundings of the region superimposed on the image and the display device to clearly indicate the organ region, means for varying the threshold for adjusting the specified organ region to an appropriate range, and variable the threshold Means for controlling the surroundings of the organ region specified in the explicit means based on a threshold variable by the means, and obtaining the surroundings of the organ region by interpolation. Display device.

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