JP2005081046A - Stereotaxy supporting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stereotaxy supporting system which sets Z coordinate values, an X coordinate axis, and a Y coordinate axis for a targeted point of a surgery easily and accurately. <P>SOLUTION: Since a detection processing means for positions of all markers for displaying a plurality of markers by removing a head region from CT image data is provided on the stereotaxy supporting system, false discrimination in the head region on discriminating groups of the markers is prevented by removing the head region. Since the detection processing means for positions of all markers includes a binary image generating means for binarizing a CT image 1 by prescribed CT values, a head region removing means for removing a part corresponding to a head part from the binary image, and a marker coordinates calculating means for calculating the coordinates of each marker by separating each point of the markers after performing a binary treatment on the image in which the part corresponding to the head part is removed by the head region removing means, the false discrimination in the head part 2 on discriminating marker groups 3a and 3b of markers is prevented by precisely removing the entire head part from the CT image. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stereotaxic surgery support system using an image diagnostic apparatus such as an X-ray CT apparatus.

  Stereotaxic surgery involves attaching a surgical ring that can set the position of an elongated suction tube, etc., to the patient's head with a three-dimensional coordinate scale of the XYZ axes, and suctioning with a three-dimensional coordinate target to the surgical target point in the deep brain. This is a surgical method in which a tube or the like reaches a surgical target point and is treated. In order to determine the three-dimensional coordinate scale of the surgical target point, a gauge plate with a built-in bar-shaped marker is attached to the surgical ring, and the surgical ring is mounted on the patient's head, and the X-ray CT apparatus is used. The image is taken and the coordinate axis is specified by using a visceral rod-like marker image on the gauge plate shown in the tomographic image of the head, and a three-dimensional coordinate scale of the surgical target point such as a tumor or bleeding position in the brain is obtained.

  In the conventional stereotaxic device, it is necessary to read the X, Y, and Z axis coordinate scales of the surgical target point using the CT display image 1 as shown in FIG. The obtained X, Y, Z coordinate scales are set in the stereotaxic device, and an instrument such as a suction tube is positioned. In order to obtain this coordinate scale, the following operation was manually performed on the CT image 1. First, the horizontal X-axis is set by dragging between the large X-axis markers 17a and 17b at the center of each of the left and right markers with the mouse. Next, the center of the X axis is obtained and the mouse is dragged so as to pass through the center to set the vertical Y axis. Since the Y axis is a perpendicular bisector of the X axis, it can be automatically determined once the X axis is determined. The intersection of the X axis and the Y axis is the center of the surgical ring. Thereafter, when the surgical target point 30 is set by clicking the mouse, the click position, that is, the X-axis scale and the Y-axis scale of the surgical target point 30 are automatically displayed. Further, between the Z axis markers 9a and 10a and between the Z axis markers 9b and 10b in the body axis direction of the patient positioned outside the left and right marker groups, the Z coordinate scale is also obtained from the average value thereof. The distance between the Z-axis markers 9a and 10a and between the Z-axis markers 9b and 10b is the distance from the center of the surgical ring to the slice plane of the surgical target point, and the distance between the Z-axis markers depends on this distance. It is configured to change. In this way, all the X, Y and Z coordinate scales of the surgical target point can be obtained.

However, since each point of the marker group described above is a small point on the CT image, it is difficult to accurately determine the position with the mouse. Therefore, in a conventional stereotactic brain surgery support system, it has been proposed to manually set a rough region of interest ROI for a marker and search for the marker from the ROI based on the CT value (for example, Patent Document 1).
Japanese Patent Laid-Open No. 2001-170072

  However, the conventional stereotactic brain surgery support system has poor reproducibility of manual coordinate setting, and it is necessary to set the ROI by manual delicate mouse movement for a small marker. There was a problem with complexity.

  An object of the present invention is to use an X-ray CT apparatus or the like so that the X-coordinate axis of the head surgery ring can be specified, and the X-coordinate scale, Y-coordinate scale, and Z-coordinate scale of the surgical target point can be accurately acquired. To provide a stereotaxic surgery support system.

  In order to achieve the above object, the present invention provides a plurality of gauge plates with a plurality of rod-shaped markers corresponding to the X-axis and Z-axis, and a surgical ring having XYZ-axis scales attached to the patient's head. A stereotactic brain surgery support system that acquires CT slice image data, and can specify a surgical target point in the patient's head from the head image as a display image of the CT slice image data and the plurality of marker images by the scale. In this case, for each CT slice image data, data corresponding to the head image is removed from the data, and only the data corresponding to the plurality of marker images is left and only the remaining data is selected, whereby the X axis, Y A processing device for drawing an axis and a Z-axis on the display image. The processing device displays the Z-axis coordinate value of the surgical target point determined for each CT slice image data on the display image. By designating the surgical target point on the display image on which the X and Y axes are displayed, the X axis coordinate value and the Y axis coordinate value of the surgical target point are also displayed on the display image. And

  Further, in the present invention described in claim 2, in the apparatus described in claim 1, the processing device designates the surgical target point in advance, so that the X axis of the surgical target point is determined immediately after the XY coordinates are determined. A coordinate value and a Y-axis coordinate value are output.

  Further, in the present invention according to claim 3, in a state where a gauge plate containing a plurality of rod-shaped markers corresponding to the X axis and the Z axis and a surgical ring having an XYZ axis scale are attached to the patient's head, A transmission X-ray irradiated from the X-ray source of the line CT apparatus through the patient's head is detected by a detector to obtain a plurality of CT slice image data, and a head image as a display image of the CT slice image data In the stereotaxic surgery support system having a processing device capable of identifying a target surgical point in a patient's head from the plurality of marker images using the scales, the processing device is provided with a head from the data for each CT slice image data. Marker position detecting means for leaving only data corresponding to the plurality of marker images by a head region removing means for removing data corresponding to the image, and the X axis by selecting only the remaining data, Axis, the Z-axis, characterized in that a and Z coordinate values calculated automatically means and the XY coordinate axis automatic setting means for drawing on said display image.

  Furthermore, in the present invention described in claim 4, in the apparatus described in claim 3, the XY coordinate axis automatic setting means designates the surgical target point in advance so that the surgical target point is set immediately after the determination of the XY coordinate. The X-axis coordinate value and the Y-axis coordinate value are output.

  As described above, according to the stereotaxic surgery support system of the present invention, by performing the process of removing the region of the head, it is possible to prevent misjudgment at the head when discriminating the marker group and to trust the marker group. Position information with high characteristics can be obtained, and the Z coordinate, X coordinate axis, and Y coordinate axis of the surgical target point can be set easily and accurately.

  According to the stereotaxic surgery support system of the present invention described in claim 2, the X-axis coordinate value and the Y-axis coordinate value of the surgical target point immediately after the determination of the XY coordinate by specifying the surgical target point in advance. The output information with high reliability can be easily confirmed.

  According to the stereotaxic surgery support system of the present invention as set forth in claim 3, the gauge plate and the XYZ axes can be obtained simply by adding various means to the processing apparatus without changing the basic configuration of the conventional X-ray CT apparatus. When X-rays are irradiated to a patient's head to which a surgical ring having a scale is attached, the processing device removes the head region from CT image data acquired via a detector and obtains only a plurality of marker images. In addition, it is possible to obtain a stereotaxic surgery support system that prevents the erroneous determination caused by the presence of the head region when discriminating the marker group and improves the reliability of the position information of the marker group.

  According to the stereotaxic surgery support system of the present invention as set forth in claim 4, various means are added to the processing apparatus without changing the basic configuration of the conventional X-ray CT apparatus, and the surgical target point is set in advance. By specifying, it is possible to easily confirm highly reliable output information of the X-axis coordinate value and the Y-axis coordinate value of the surgical target point immediately after the determination of the XY coordinates.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a schematic configuration of a stereotaxic surgery support system according to an embodiment of the present invention.
The X-ray CT apparatus 31 includes an X-ray source and a scanner 32 having a detector that detects transmitted X-rays irradiated to the patient from the X-ray source, a bed 33 on which the patient is placed, and data detected by the detector. A processing apparatus 12 for processing and an image display apparatus 11 capable of displaying an image or the like reconstructed by the processing apparatus 12 are provided. The processing device 12 includes a first binarized image creating unit 20, which will be described in detail later, a marker position detecting unit 19 including a head region removing unit 21, and a marker coordinate calculating unit 22, and an automatic calculation of Z coordinate values. Means 23 and XY coordinate axis automatic setting means 24 are provided. On the head of the patient 7 on the bed 33, a surgical ring 6 having a gauge plate containing a plurality of bar-shaped markers 3 corresponding to the X axis and the Z axis and an XYZ axis scale is attached.

FIG. 2 is a flowchart showing the operation of the stereotaxic surgery support system described above.
In this flowchart, a surgical ring having a gauge plate containing a plurality of marker bars is attached to a patient's head to determine the three-dimensional coordinates of the surgical target point of the patient's head, and the patient's head is attached to the patient's head while attached. FIG. 11 shows a step after obtaining a display image as shown in FIG. 10 taken by a line CT apparatus and showing a patient's head together with a rod-shaped marker image. First, in step S1, marker position detection processing is performed to detect all markers from the CT image data and obtain their positions. The marker position detection means 19 for performing the marker position detection process converts the CT image data into a predetermined CT value range and other ranges, for example, a CT value range of −500 to +1800 and other ranges as shown in step S2. First binarized image creating means 20 for binarizing, head region removing means 21 for removing a portion corresponding to the head from the binarized image data as shown in steps S3 to S5, As shown in steps S6 and S7, the second region is separated from the image data obtained by removing the portion corresponding to the head by the head region removing means 21 to separate each point of the marker. And a marker coordinate calculation means 22 for calculating each marker coordinate.

  In the processing of this flowchart, processing such as binarization and head region removal is performed on the CT image data, but these are exclusively used to create an image used for internal processing. Since an image displayed on the image display device 11 and shown to the operator is not created, it is called CT image data or CT slice image data. The image displayed on the image display device 11 is a display image as shown in FIG.

  In step S <b> 2, the first binarized image creating process is performed by the first binarized image creating unit 20 of the marker position detecting unit 19. The data of the CT image 1 at this time includes a patient's head 2 and marker groups 3a and 3b on both sides thereof as shown in a simplified manner in FIG. A binarized image creation process is performed on the CT image 1 data within a preset threshold range.

  For example, in the binarized image creating process by the binarized image creating means 20, a pixel having a CT value in the range of −500 to +1800 in the CT image data is set to one value 1 and a pixel outside this range is set to the other value. The value is 0. Here, when the CT value from −500 to +1800 is binarized so as to be one value, each point in the left and right marker groups 3a and 3b in the binarized image 4 is represented as shown on the right side of FIG. Although it will connect for every right and left, the whole head 2 can also be made into one continuous area | region. However, for example, if the CT value of +50 to +1800 is binarized so as to be one value, the binarized image separates each point in the left and right marker groups 3a and 3b as shown on the left side of FIG. However, the area of the head 2 does not become one as in the case described above, and a large number of small areas remain separated and are easily confused with each point of the marker groups 3a and 3b. False detection is likely to occur.

  After creating the binarized image 4 of the plateau for the purpose of removing only the region of the head 2 from the CT image data, the head region removing means 21 re-adds each of the marker groups 3a and 3b again in step S3 in step S3. A labeling process is performed for the purpose of separating points. In this labeling process, as shown in FIG. 4, different numerical values (labels) are assigned to the first binarized image 4 for each continuous region to obtain a labeled image 5. Here, for example, the label value 100 is assigned to the continuous area of the left marker group 3a, the label value 101 is assigned to the continuous area of the head 2, and the label value 102 is assigned to the continuous area of the right marker group 3b.

  The head region removing unit 21 performs a continuous region area calculation process in subsequent step S4. This continuous area calculation processing calculates the area (number of pixels) for each continuous area labeled on the labeling image 5 described above, that is, the number of pixels for each continuous area, and the label value for one continuous area. The number of pixels is stored in the array PX [label value, number of pixels] as a set of data.

  The head area removing unit 21 performs the maximum area deleting process in the subsequent step S5. This maximum area deletion process is performed continuously using the CT image data shown in FIG. 3, the labeling image 5 shown in FIG. 4, the number N of continuous areas, and the number of pixels for each continuous area calculated in step S4. The continuous region of the head 2 having the largest number of pixels is searched from the array PX [label value, number of pixels], and the label value V is obtained. Further, the pixel on the CT image data corresponding to the pixel matching the label value V from the labeling image 5 is replaced with −1000, while the non-matching pixel is copied as it is. At this time, the CT display image 1 is not overwritten and a separate image area is secured, and the processed CT image data is held separately.

  Thereafter, the marker coordinate calculation means 22 first performs a second binarized image creation process in step S6. In the second binarized image creation process, the binarization process is performed to extract the marker groups 3a and 3b using the CT image data processed in step S5. At this time, for example, a pixel in the CT value range of +50 to +1800 in the processed CT image is set as one unit 1, and a pixel outside this range is set as the other unit 0. A new binarized image in which the region of the head 2 is removed from the CT image 1 shown in FIG. 3 by the second binarized image creation process and each point of the left and right marker groups 3a and 3b is separated. Can be obtained.

  In the next step S7, the marker coordinate calculation means 22 performs marker center coordinate calculation processing in order to specify a reference point for distance measurement and coordinate determination. This marker center coordinate calculation process is performed by a labeling process using the second binarized image in step S6. As shown in FIG. 5, a labeling image 7 is obtained by assigning a different numerical value (label) to each image continuous area of each point in the second binarized image 6. Here, labels 11 to 16 are assigned to each continuous region of one value 1 corresponding to each point of the left and right marker groups 3a and 3b. Subsequently, the center coordinates of each continuous area to which the labels 11 to 16 are assigned are obtained. The central coordinates have the center of gravity of each continuous area as a central point. This is the first procedure for determining three-dimensional coordinates (XYZ axis coordinates). As another simple marker center coordinate calculation process, the pixel value of the CT image corresponding to each continuous area may be examined, and the coordinates of the maximum value pixel in the area may be calculated as the center point. In any case, the calculated marker center coordinates Q for M markers exist from Q1 [X1, Y1] to QM [XM, YM], and are stored as an array.

  The labeling process described above is a process of assigning a different label for each continuous component with the same label (number) in connected pixels (continuous components). There are various labeling methods, but an example is introduced. First, a CT image is scanned to find unlabeled pixels and a new label is applied. Then, the same label is attached to all the pixels that are continuous with this pixel. By continuing this operation until there are no more pixels to label, one continuous component is labeled the same. Thereafter, returning to the beginning, if there is a pixel that is not yet labeled, a new label is attached and the above-described processing is repeated. When the entire image has been scanned, the process ends.

  Next, the Z coordinate axis automatic calculation means 23 performs the Z coordinate automatic calculation process of step S8 shown in FIG. The concept of Z-axis marker automatic detection will be described. As shown in FIG. 6, in a state in which the portion corresponding to the head is removed from the CT image data to form a binarized image, the binarized image is scanned vertically from the upper left corner 8, and two Z-axis markers 9a, Scan is stopped when 10a is detected. The distance between the two detected Z-axis markers 9a and 10a is the Z coordinate axis. The right side is also scanned from the upper right corner, and the two Z-axis markers 9b and 10b are similarly detected. Actually, if the two leftmost points and the two rightmost points are selected from the marker coordinates obtained in step S7 shown in FIG. 2, the Z axis markers 9a and 10a and the Z axis markers are selected. 9b and 10b are detected. Next, distances between the left and right Z-axis markers 9a and 10a and the Z-axis markers 9b and 10b are calculated, and the average value is used as the average Z-coordinate value. Since the pixel size is recorded in the image supplementary information, the distance between the two points can be obtained by calculation based on this.

  Next, the XY coordinate axis automatic setting means 24 automatically sets the X coordinate axis and the Y coordinate axis in step S9 shown in FIG. In the automatic setting process of the X coordinate axis and the Y coordinate axis, the four points of the Z coordinate markers 9a, 9b, 10a, and 10b previously extracted in step S8 are removed from all the markers, and the X axis markers are extracted from the remaining markers. To do. As a method for extracting the X-axis marker, there are a method of determining by the number of pixels of the marker, a method of determining by the center position of the marker, and the like.

  In the method of discriminating by the number of pixels, that is, the area of the marker, the X-axis markers 17a and 17b are slightly larger than the other markers as shown in FIG. To extract the X-axis markers 17a, 17b. Further, in the method of discriminating by the center position of the markers, the X-axis markers 17a and 17b are extracted by utilizing the fact that the marker located at the center in the vertical direction in the left and right marker groups is the X-axis marker.

  In any case, if the extracted left and right X-axis markers 17a and 17b are connected by a line, an X-axis line segment can be drawn. A vertical bisector perpendicular to the X axis at the midpoint of the X axis line segment becomes the Y axis.

  According to such a stereotactic brain surgery support system, since the head region is removed from the CT image data and the all marker position detection means 19 for displaying a plurality of markers is provided, the head region is removed. In the determination of the marker group, it is possible to prevent erroneous determination in the head region, and the Z coordinate value, X coordinate axis and Y coordinate axis of the surgical target can be obtained fully automatically as shown in FIG. Since it is not necessary to manually move the mouse finely with the mouse, the X, Y, and Z values can be obtained easily and accurately. In particular, the entire marker position detecting means 19 includes a first binarized image creating means 20 for binarizing the data of the CT image 1 into a range of −500 to +1800 and other pixels in terms of CT values, and this binary value. A head region removing unit 21 for removing a portion corresponding to the head from the digitized image, and performing a second binarization process on the image from which the portion corresponding to the head is removed by the head region removing unit 21 By having a marker coordinate calculation means 22 that separates each point of the marker and calculates each marker coordinate, the entire head is accurately removed from the CT image, and the marker groups 3a and 3b are automatically discriminated. In this case, erroneous determination caused by the image of the head 2 can be prevented.

  By simply giving a CT image with reference to FIG. 7, the position of the marker is automatically detected from the CT image data, the Z-axis marker is determined, the distance between the Z-axis markers is calculated, and the Z coordinate of the slice A value can be calculated. Further, the X-axis marker can be automatically detected, and the X-axis and the Y-axis can be automatically determined. Therefore, if the surgical target point 30 is first designated with the mouse, the X, Y, Z coordinate values of the surgical target point 30 are automatically calculated, and the calculation result can be displayed on the screen. .

Next, a stereotaxic surgery support system according to another embodiment of the present invention will be described.
The operation of the stereotaxic surgery support system in this embodiment is the same as that in the flowchart shown in FIG. 1, and at least one of the Z coordinate value automatic calculation process in step S8 and the XY coordinate axis automatic setting process in step S9 is all performed. The difference is from the automatic to semi-automatic processing. Here, a case where the XY coordinate axis automatic setting process shown in step S9 is performed semi-automatically is illustrated. In this example, when the operator moves the mouse cursor on the CT display image displaying only the points of the left and right marker groups 3a and 3b and approaches the X-axis marker 17a of the left marker group 3a, As shown in FIG. 9, marker highlighting means for highlighting the marker 17a at the shortest distance from the mouse cursor 18 in red or the like is used. This highlighting can be set to be executed only when the mouse cursor 18 approaches within a predetermined distance.

  If one of the markers is selected and the one highlighted in red or the like is the X-axis marker 17a, when the operator clicks the mouse button, the tip of the X-axis marker 17a and the mouse cursor 18 will be displayed. They are connected by a display line 18a. Next, when the mouse is moved to bring the mouse cursor 18 close to the right marker group 3b, the marker highlighting means determines the shortest distance marker within a predetermined distance from the mouse cursor 18, and the previous marker is displayed. As in the case, the marker is highlighted in red or the like. If the highlighted marker is the X-axis marker 17b, when the operator clicks the mouse button, the previously selected X-axis marker 17a and the currently selected X-axis marker 17b can be connected with a line. . Thus, the X axis can be obtained, and this perpendicular bisector becomes the Y axis. The marker display highlighting means has been described with respect to the example in which the X axis markers 17a and 17b are highlighted. However, the marker highlighting means is not limited to this, and the marker highlighting means includes the markers 3a and 3b, the axis markers 9a, 9b, 10a, and 10b. Markers may also be highlighted.

  By using such marker highlighting means, even if the marker groups 3a and 3b are a set of close points, a desired marker can be easily selected by highlighting a desired coordinate axis. Can be prevented, and the correct X-axis and Y-axis can be drawn.

  In the above description, the stereotactic surgery support system using the surgical ring attached to the patient's head has been described. However, the stereotactic surgery support system is configured as an X-ray CT apparatus incorporating the stereotaxic surgery support system. It can also be applied as a stereotactic brain surgery support system that acquires a plurality of CT slice image data with the surgical ring attached to the patient's head.

1 is a schematic configuration diagram showing a stereotaxic surgery support system according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the stereotaxic surgery assistance system shown in FIG. It is a top view of the image which shows the binarized image creation process of the stereotaxic surgery operation support system shown in FIG. It is a top view of the labeling image which shows the labeling process of the stereotaxic surgery assistance system shown in FIG. It is a top view of the image which shows the marker center coordinate calculation process of the stereotaxic surgery operation support system shown in FIG. It is a top view of the binarized image which shows the Z coordinate automatic calculation process of the stereotaxic surgery operation support system shown in FIG. It is explanatory drawing which shows the coordinate system of the ring for a surgery. It is a top view of the binarized image which shows the XY coordinate axis automatic setting process of the stereotaxic surgery assistance system shown in FIG. It is a principal part top view of the binarized image which shows the XY coordinate axis setting process of the stereotaxic surgery assistance system by other embodiment of this invention. It is a top view which shows CT display image of the head which attached the ring for surgery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CT image 2 Head 3, 3a, 3b Marker group 4 Binary image 5 Labeling image 6 Surgical ring 7 Patient 9a, 10a Z axis marker 9b, 10b Z axis marker 11 Image display device 12 Processing device 17a, 17b X Axis marker 18 Mouse cursor 18a Display line 19 Marker position detection means 20 Binarized image creation means 21 Head area removal means 22 Marker coordinate calculation means 23 Z coordinate value automatic calculation means 24 XY coordinate axis automatic setting means 31 X-ray CT apparatus 32 Scanner 33 Sleeper

Claims (4)

A plurality of CT slice image data is obtained with a gauge plate containing a plurality of bar-shaped markers corresponding to the X-axis and Z-axis, and a surgical ring having XYZ-axis scales attached to the patient's head. In a stereotactic brain surgery support system that can identify a surgical target point in a patient's head from the head image as a display image of image data and the plurality of marker images by the scale, the data for each CT slice image data The data corresponding to the head image is removed from the image, and only the data corresponding to the plurality of marker images is left. By selecting only the remaining data, the X, Y, and Z axes are drawn on the display image. The processing apparatus displays the Z-axis coordinate value of the surgical target point determined for each CT slice image data on the display image, and sets the surgical target point to the X-axis and Y-axis. axis By specifying on the display image displayed, stereotaxic surgery assistance system X-axis coordinate value of the operation target point and the Y-axis coordinate value is also characterized in that displayed on the display image. 2. The apparatus according to claim 1, wherein the processing device outputs the X-axis coordinate value and the Y-axis coordinate value of the surgical target point immediately after the determination of the XY coordinate by designating the surgical target point in advance. Stereotaxic surgery support system characterized by The patient's head from the X-ray source of the X-ray CT apparatus with a gauge plate incorporating a plurality of bar-shaped markers corresponding to the X-axis and Z-axis and a surgical ring having XYZ-axis scales attached to the patient's head A plurality of CT slice image data is acquired by detecting transmitted X-rays irradiated through the head, and a head image as a display image of the CT slice image data and the plurality of marker images are displayed on the scale according to the scale. A stereotactic brain surgery support system having a processing device capable of specifying an intraoperative head target point, wherein the processing device removes data corresponding to the head image from the data for each CT slice image data. Marker position detecting means for leaving only data corresponding to the plurality of marker images by the area removing means and selecting only the remaining data draws the X, Y, and Z axes on the display image. Stereotaxic surgery assistance system characterized in that a coordinate value automatic calculation unit and the XY coordinate axis automatic setting means. The XY coordinate axis automatic setting means according to claim 3, wherein the XY coordinate axis automatic setting means specifies the surgical target point in advance to determine the X axis coordinate value and the Y axis coordinate value of the surgical target point immediately after determining the XY coordinate. Stereotaxic surgery support system characterized by output.

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