JPH10334220A - Surgical operation aid navigation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow medical instruments to be reached accurately to an object position without interrupting a surgical operation by obtaining a 3-dimension image from the inside of a tubular organ such as a blood vessel in real time and navigating the image. SOLUTION: By what kind of shape, which size and what coordinate a medical instrument such as a catheter and a stent is to be displayed on a monitor image is decided (step 11). The initial coordinate value of a catheter is entered and a catheter 3-dimension image is configured (step 12). A 3-dimension image in a blood vessel is configured based on entry and measured values in the steps 11, 12 (step 13). The catheter 3-dimension image and the 3-dimension image in a blood vessel are synthesized to obtain a navigation use synthesis image and it is displayed on a monitor screen (step 14). A catheter coordinate detector reads a coordinate in the inside of the blood vessel (step 15) to obtain the catheter 3-dimension image and the 3-dimension image in a blood vessel and they are synthesized to obtain a new navigation sue synthesis image (steps 17, 18).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to blood vessels, esophagus, intestines,
The present invention relates to a surgical assisted navigation method suitable for navigation inside a tubular organ such as a bronchus when performing a surgical operation on a minute part in the tubular organ. In this specification, “surgery” means “examination and surgery”.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique for performing navigation inside an organ during surgery. As an example, the tip coordinate values in the sensor coordinate system of a plurality of probes are registered in the system, so that the corresponding tip coordinates can be input when exchanging the probe, and a predetermined conversion formula is obtained every time the probe is exchanged. There is one that can detect and display the position of the tip of the probe in use (the 4th academic lecture meeting of the Computer Aided Diagnostic Imaging Society, the 3rd academic presentation meeting of the Japan Society of Computer Aided Surgery (October 15, 1994-
16) Joint Journal Collection, pages 85 to 88).

[0003]

However, in the above-mentioned prior art, the position of the detected tip of the pointing device is displayed on an image in a surgical operation. In this case, the image is mainly a two-dimensional image. Here, "3D reconstructed image"
Although there is a description, it assists in understanding the anatomical orientation, and is not an image displayed in real time. For this reason, navigation such that a catheter, a stent, or the like device can accurately reach a target position cannot be performed.

In order to detect the position of the tip of the pointing device, it is necessary to attach a sensor to a calibration probe, a surgical probe, or the like, and to detect the position thereof. In tubular organs such as blood vessels where it is impossible to insert cameras and sensors,
I couldn't get the image from inside and navigate.

An object of the present invention is to provide a real-time three-dimensional image from inside even a tubular organ, such as a blood vessel, into which a camera, a sensor, or the like cannot be inserted. It is an object of the present invention to provide a surgical assistance navigation method capable of accurately navigating an instrument to a target position without interruption.

[0006]

The above object is based on a three-dimensional internal image of an organ constructed from a plurality of tomographic images of an organ using a central projection method and the position coordinates of a device inserted inside the organ. This is achieved by synthesizing and displaying in real time the device three-dimensional image configured as described above.

If a three-dimensional image of the inside of an organ and a three-dimensional image of a device are synthesized and displayed in real time, even in a tubular organ such as a blood vessel into which a camera, a sensor, or the like cannot be inserted, a three-dimensional image from the inside can be obtained. Images (images inside the tubular organ where the device such as a catheter is located) can be obtained and navigated in real time, so that the device can be navigated to reach the target position accurately without interrupting the operation.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart showing one embodiment of a surgery support navigation method according to the present invention.

In FIG. 1, in a step 11, on a monitor screen for displaying a synthetic image for navigation, a device such as a catheter or a stent (hereinafter collectively referred to as a catheter) is formed in any shape and size. so,
Decide what coordinate position to display. The shape of the catheter is selected from several patterns using a mouse, a keyboard, or the like, or formed into a shape desired by the user using a mouse, or the like. The size (diameter, length, etc.) of the catheter is also selected from values prepared in advance using a mouse, a keyboard, or the like, or a desired size is input. The same applies to the displayed coordinate position (xi, yi, zi) (i = 1, 2, 3,... N).

In step 12, an initial value (xj, yj, zj) (j = 0) of the catheter coordinate position is input. These initial values also form a three-dimensional image of a blood vessel. This value can be entered using a mouse or keyboard,
It is measured by a catheter coordinate position detector described later.

In step 13, the input values and measured values (xj + xi, yj + yi, zj + z) of steps 11 and 12
i) A three-dimensional (3D) image of the catheter is formed by (j = 0) and the like. Next, based on the input values and the measured values (xj, yj, zj) (j = 0) in step 12 described above, a general center projection method is used from a plurality of tomographic images of a tubular organ, here, a blood vessel, and the inside of the blood vessel (3D) image is constructed. In step 14, the three-dimensional catheter image and the three-dimensional image inside the blood vessel constructed in step 13 are combined, a combined image for navigation is obtained, and displayed on the monitor screen.

In step 15, the position coordinates of the catheter inside the blood vessel are read by a catheter coordinate position detector including an angle sensor and a two-dimensional sensor. Step 16
Then, it is checked whether or not the position coordinates (xj, yj, zj) (j = j + 1) of the catheter read in step 15 are changed. If there is a change, the process proceeds to step 17, but if there is no change, the process returns to step 15.

In step 17, the new catheter position coordinates (xj, yj, zj) (j = j + 1) are used,
A three-dimensional image of the catheter and a three-dimensional image of the inside of the blood vessel are constructed.

In step 18, the new three-dimensional catheter image formed in step 17 and the three-dimensional image of the inside of the blood vessel are synthesized, and a new synthesized image for navigation is obtained and displayed on the monitor screen. In step 19, it is checked whether or not to end the processing. When the processing is continued, the processing of steps 15 to 18 is repeated. Input of processing end is
By operation from a mouse or keyboard.

FIG. 2 is a block diagram showing an example of a hardware configuration for executing the method of the present invention. 2, a CPU 70, a main memory 71, a magnetic disk 7
2. The display memory 73, the mouse controller 75 and the catheter coordinate position detectors 77 and 78 are mutually connected by a common bus 79.

Here, the catheter coordinate position detectors 77 and 78 are used alternately and are not usually connected at the same time. As shown in the figure, the catheter coordinate position detector 77 is a sensor 1 that controls each of the angle sensors 1 to 3 (77d to 77f) attached to the catheter 77g.
The coordinate information of the catheter is detected by the controllers 77a to 77c. In this example, there are three angle sensors,
Any number is acceptable. Further, the catheter coordinate position detector 78
Converts the information obtained by the two-dimensional sensor 78b along the X and Y axes into digital data by the AD converter 78a to detect the coordinate information of the catheter.

On the magnetic disk 72, a plurality of tomographic images (including volume images obtained by MRI and the like) to be reconstructed, a program for executing each processing shown in FIG. A program for composing the original images, synthesizing and displaying them in real time, and an operation program are stored.

The CPU 70 reads the plurality of tomographic images and the execution program from the magnetic disk 72, receives the catheter position coordinate information from the catheter coordinate position detector 77 or 78, and uses the main memory 71 as shown in FIG. The processing flow is calculated and executed, and the result (combined image for navigation) is sent to the display memory 73 and displayed on the CRT monitor 74.

The mouse 76 connected to the mouse controller 75 is used for designating initial position coordinates and the like when calculating a three-dimensional catheter image and the like. The navigation synthesized image thus obtained is stored on the magnetic disk 72 as needed.

FIG. 3 is a diagram showing an example of a composite image for navigation according to the method of the present invention. Here, an example is shown in which the navigation composite image 20 is displayed on the CRT monitor 74. As described above, the navigation synthesized image 20 is composed of a three-dimensional image 20a of the inside of a blood vessel obtained by a general central projection method using a plurality of tomographic images of a tubular organ, here, a blood vessel, and a catheter tertiary image by computer graphics. It is composed of an original image 20b. The position, size, shape, and the like of the catheter three-dimensional image 20b are determined based on designated initial values.

FIG. 4 is a block diagram showing an example of the catheter coordinate position detector in FIG. Here, an angle sensor is used for catheter coordinate position detection.

The angle sensors 1 to 3 (77d to 77f)
One end is attached to the catheter 77g, and the other end is fixed to the ceiling 30. Instead of the ceiling 30, it may be fixed to another stationary part. Each time the catheter 77g is inserted and moved into the blood vessel of the patient 31, R1 of the catheter 77g is
3 (32-34) moves. This R1-3 (32-3
The distance, angle, etc. of the movement of 4) are measured by the angle sensors 1 to 3 (77).
d-77f) to detect the position coordinates of the current catheter 77g. The angle sensor 1 (77d) detects the state of R1 (32). Similarly, R2 (33), R3
Regarding the state of (34), the angle sensor 2 (77e),
3 (77f) detects. The number of angle sensors is shown in the illustrated example (3
).

FIG. 5 is a block diagram showing another example of the catheter coordinate position detector in FIG. Here, a two-dimensional sensor is used for detecting the catheter coordinate position. Patient 31
The X-ray tubes (35a, 35b) are installed in the X and Y directions around the position of, and the two-dimensional sensors (78b1, 7
8b2). X-ray tubes (35a, 35b)
Irradiates X-rays from the sensor and measures the intensity using a two-dimensional sensor (78b
, 78b2) and AD converters (78a1, 78a).
By performing the AD conversion in a2), the position coordinates of the tip of the catheter 77g in the patient 31 are detected.

Hereinafter, a method of constructing a three-dimensional image inside an organ used in the method of the present invention will be described with reference to FIGS. FIGS. 6 to 8 show a method of constructing a three-dimensional image from a plurality of tomographic images by a general center projection method (Japanese Patent Application No. Hei 6 (1994) -294).
-3492).

First, a description will be given of coordinate transformation by central projection in the above-described method for constructing a three-dimensional image. The conversion of the pixel coordinates of each tomographic image to the coordinates on the projection surface when projecting each tomographic image on the projection plane by the central projection is performed as follows.

In the example shown in FIG. 6, the coordinate system is set such that the projection plane, the tomographic image plane, and the xy plane are parallel to each other to simplify the description. In FIG. 6, x, y,
z is each axis of the three-dimensional coordinate system (x, y, z), and point e (x1,
y1, d1) is the position of the viewpoint e, P point (X, Y) is a point on the projection plane (corresponding to the display screen) 21, and S point (x0, y0,
d0) is a point where the straight line 22 passing through the point e (x1, y1, d1) and the point P (X, Y) intersects with the tomographic image 23A.

D is the position of the projection plane 21 (on the z-axis).
And can be set arbitrarily. d0 is the position (on the z-axis) of the tomographic image 23A and is determined at the time of measurement. d1 is the z coordinate of the viewpoint e.

According to this, the following equation is established. X = {(D−d1) / (d0−d1)} × (x0−x1) + x1 (1) Y = {(D−d1) / (d0−d1)} × (y0−y1) + y1 ( 2) x0 = {(d0-D) / (d1-D)} * (x1-x) + X (3) y0 = {(d0-D) / (d1-D)} * (y1-y) + Y … (4)

When the projected image is displayed on a display screen (not shown) corresponding to the projection plane 21 by 512 pixels vertically × 512 pixels horizontally, X and Y take values from -256 to +256. A tomographic image 23 of d0 for each X and Y
On A, x0 and y0 are determined by the above equations (3) and (4), and which point is to be projected is determined. Since there are a plurality of tomographic images 23 and a plurality of d0, a plurality of points x0 and y0 to be projected are determined for one set of X and Y.

In the same coordinate system, tomographic images 23B to 23E are prepared in addition to the tomographic image 23A, and a diagram viewed from the y-axis direction is shown in FIG. In FIG. 7A, tomographic images 23A to 23E are tomographic images obtained at equal intervals in the same direction for the same object (although they are equal in the illustrated example, they are not necessarily equal). On the tomographic image 23B, the organ regions B1, B2, and B3 are emphasized and written. When the organ regions B1, B2, B3 are projected on the projection plane 21, B1 ',
B2 'and B3'. Similarly, when the organ regions C1 and C2 of the tomographic image 23C are projected on the projection plane 21, they become C1 'and C2'.

Here, the projection data (here, B1 ',
When writing B2 ', B3'; C1 ', C2') in a display memory (not shown), first write projection data which is farther from the viewpoint e to obtain a three-dimensional effect. ,
Later projection data is overwritten. Therefore, here, the projection data B is obtained from the projection data C1, C2.
Since 1, B2 and B3 are farther than the viewpoint e, the projection data B1 ', B2' and B3 'are written first, and the projection data C1' and C2 'are overwritten later. In FIG. 7A, the projection data B1 ', B2', B3 '; C
1 'and C2' are shown apart from the projection plane 21, respectively.
This corresponds to the projection data B1 ', B2',
B3 '; This is merely to make the order of C1', C2 'easy to understand, and the projection data B1', B2 ', B3' to be written first
In addition, the projection data C1 'and C2' overwritten thereon are actually written on the projection plane 21.

FIG. 7B shows a more generalized example than FIG. 7A, and shows an example in which the projection plane and the tomographic image plane are not parallel. In this case, tomographic images 23A, 23B, 23C
, It is necessary to create tomographic images 23a, 23b, 23c,... Directed to a plane parallel to the projection plane 21 by interpolation. Others are the same as in the case of FIG. In addition,
b1 ';c1', c2 ';d1' are organ regions b1; c1, c2; on the interpolated tomographic images 23b, 23c, 23d;
d1 is projection data.

FIG. 8 is a diagram for explaining coordinate conversion by central projection when the viewpoint, tomographic image, and projection plane have a more complicated positional relationship. The point S (x0, z0,
y0) indicates that the projection result is a point P (x, y, z) on the projection plane.

In FIG. 8, the conversion of the pixel coordinates of the tomographic image 23 to the coordinates on the projection surface 21 in the projection of the tomographic image 23 onto the projection surface 21 by the central projection is performed as follows. Here, a is a point at which the x-axis intersects with the projection plane 21, b
Is a point at which the y-axis intersects with the projection plane 21, and c is a z-axis and the projection plane 21
Is the intersection of

Further, α is an angle formed by a line projected from the origin to the projection plane 21 on the zx plane and the x axis, β is an angle formed by the perpendicular on the xz plane, and point e (x1, y1, z1) is the position of the viewpoint e, P point (x, y, z) is a point on the projection plane (corresponding to the display screen) 21, and S point (x0, z0, y0) is e point (x1, y1). , Z1) and a straight line 2 passing through point P (x, y, z)
Assuming that the point 2 intersects the tomographic image 23, the following equation is established.

First, the projection plane 21 is represented by (x / a) + (y / b) + (z / c) = 1 (5). Further, a straight line 22 passing through the point e (x1, y1, z1) and the point P (x, y, z) is (x0-x) / (x1-x) = (y0-y) / (y1-y) = (Z0−z) / (z1−z) (6)

When the projection plane 21 is at the point C1 (xc1, yc1, zc
When passing through 1), k1 = sinα k2 = cosα / sinβ k3 = cosα · cosβ / sinβ ai = 1 / a bi = 1 / b ci = 1 / c, and z = [X · k1−Y · k2−yc1・ K3 − ｛(ci · k3 · zc1) / bi｝ + ｛(ai · k3 · X) / (bi · cosα)｝ − ｛(ai · k3 · xc1) / bi｝] / [1-｛(ci)・ K3) / bi｝ + {(ai · k3 · sinα) / (bi · cosα)}] (7) x = (X−z · sinα) / cosα (8) y = [yc1 + ｛− ci · (Z-zc1) -ai · (x-xc1)｝] / bi (9)

Here, the above C1 point (xc1, yc1, zc
In 1), for example, a point at which a perpendicular line drawn from the viewpoint e (x1, y1, z1) to the projection surface 21 intersects with the projection surface 21 (the distance between this point and the viewpoint e is h): zc1 = z1 +-[ ^{h / sqrt {1+ (c 2} / a 2) + (c 2 / b 2)}] ( "z1 + -" in "-" when the z0 <zc1) ... (10) xc1 = x1 + {c · (z1 −zc1) / a｝ (11) yc1 = y1 + {c · (z1−zc1) / b} (12)

When the projected image is displayed on a display screen (not shown) corresponding to the projection plane 21 with 512 pixels vertically × 512 pixels horizontally, X and Y take values from -256 to +256. The above (7) for each X and Y,
X and y are determined by the equations (8) and (9). x1 at point e,
Since y1 and z1 are given arbitrarily, the following (13), (14)
From the equation, the coordinates x0, x of the pixel S on the tomographic image of y0 = d0
z0 is determined. x0 = {(d0-y) / (y1-y)} × (x1-x) + x (13) z0 = {(d0-y) / (y1-y)} × (z1-z) + z ( 14) Since there are a plurality of tomographic images and a plurality of d0, a plurality of points x0 and y0 to be projected are determined for one set of X and Y.

Note that R in FIG. 8 indicates the distance from the viewpoint e to the point S, and this R is a parameter for calculating the pixel value (luminance) at the point P. In the case of a depth image, the pixel value at point P is the maximum value Rmax of the set pixel value (luminance).
Is proportional to the value obtained by subtracting the above R from.

A three-dimensional image may be constructed by a volume rendering method that takes opacity into account (Marc Levoy,
"Display of Surface From Volume Data" IEEE Comput
er Graphics and Application, May, pp. 29-37, 1988).

[0042]

As described above, according to the present invention, even in a tubular organ such as a blood vessel into which a camera or a sensor cannot be inserted, a three-dimensional image from the inside is obtained in real time for navigation. Therefore, there is the effect that the instrument can be accurately navigated to the target position without interrupting the operation.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of the method of the present invention.

FIG. 2 is a block diagram showing an example of a hardware configuration to which the method of the present invention can be applied.

FIG. 3 is a diagram showing an example of a composite image for navigation according to the method of the present invention.

FIG. 4 is a configuration diagram illustrating an example of a catheter coordinate position detector in FIG. 2;

FIG. 5 is a configuration diagram showing another example of the catheter coordinate position detector in FIG. 2;

FIG. 6 is an explanatory diagram of a method of constructing a three-dimensional image by a center projection method used in the method of the present invention.

FIG. 7 is an explanatory diagram of a method of constructing a three-dimensional image by a center projection method used in the method of the present invention.

FIG. 8 is an explanatory diagram of a method of constructing a three-dimensional image by a center projection method used in the method of the present invention.

[Explanation of symbols]

 Reference Signs List 20 synthetic image for navigation 20a three-dimensional image of inside of blood vessel 20b three-dimensional image of catheter 70 CPU 71 main memory 72 magnetic disk 73 display memory 74 CRT monitor 75 mouse controller 76 mouse 77, 78 catheter coordinate position detector 79 common bus

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kawa-Saki ▼ Shinji 1-1-1 Uchikanda, Chiyoda-ku, Tokyo Inside Hitachi Medical Co., Ltd. (72) Kenji Takiguchi 1-chome Uchikanda, Chiyoda-ku, Tokyo No. 1-14 Inside Hitachi Medical Corporation

Claims (1)

[Claims] 1. An organ three-dimensional image formed from a plurality of tomographic images of an organ using a central projection method, and a device three-dimensional image formed based on position coordinates of a device inserted inside the organ. Surgery-assisted navigation method, which synthesizes and displays in real time.