CN100454340C

CN100454340C - Visualization method for virtual incision of ductal organs

Info

Publication number: CN100454340C
Application number: CNB2007100374921A
Authority: CN
Inventors: 曹立基; 梁家斌; 赵俊
Original assignee: Shanghai Jiao Tong University
Current assignee: Shanghai Jiao Tong University
Priority date: 2007-02-13
Filing date: 2007-02-13
Publication date: 2009-01-21
Anticipated expiration: 2027-02-13
Also published as: CN101013506A

Abstract

A visualization method for virtual incision of ductal organs belongs to the technical field of image processing. The present invention firstly divides the organ image from the original medical data, then finds out the central path of the ductal organ, then determines the normal vector of the section surface for each point on the central path, and then uses the approximate distance from the point to the organ wall to is the radius of the sphere, according to the normal vector of the cross-sectional surface, use the hemisphere to perform collective subtraction on part of the colon volume data, thereby cutting off the invalid part of the data, and finally perform region growth on the remaining volume data to ensure connectivity, and then interactively display. The invention makes the diagnosis of the colon not limited by the viewing angle of the endoscope, becomes intuitive and fast, and at the same time does not bring deformation to the anatomical structure of the inner wall of the colon.

Description

Visual method for virtual incising tubular organ

Technical field

What the present invention relates to is a kind of method of technical field of image processing, is specifically related to a kind of visual method for virtual incising tubular organ.

Background technology

At present, utilize medical imaging datas such as CT, MRI, what the pipeline internal organs were carried out that three-dimensional visualization is rebuild and inspections and examinations are mainly adopted is the method for virtual endoscope.This technical modelling the traditional optical endoscope body in cavity, advance, internally the internal organs inwall is observed with the visual angle of endoscope optical.The advantage of this technology has been to overcome the traditional optical endoscope and has needed the shortcoming in the endoscope body insertion human body, is a kind of complete touchless inspection method.Yet, the shortcoming of existing virtual endoscopic techniques is to peep in viewing angle still is confined to, there is very big restriction at the visual angle, directly perceived inadequately during diagnosis, omission place is arranged easily, can't observe by the configuration to internal organs from the outside, directly perceived inadequately to the location of focus, and be difficult to remove its other impurity of ponding in the intestines, diagnosis is brought influence.

Find through literature search prior art, Joel G..Fletcher etc. are in Journal ofComputer Assisted Tomography (computer aided tomography magazine) (the 25th the 6th phase of volume of calendar year 2001, the 864-869 page or leaf) " Feasibility of Planar Virtual Pathology:A New Paradigm in Volume-Rendered CT Colonography " (planar virtual pathology feasibility: a kind of novel type that is used for a volume drawing CT virtual colonoscopy) literary composition of delivering on, propose a kind of plane that utilizes the segment colon has been carried out virtual incision, and then be mapped to the method for colon being observed behind the two dimensional surface.This method can partly solve the problem of angle limitations when peeping diagnosis in virtual, increases the intuitive of diagnosis, accelerates diagnosis speed.Its deficiency is: this method can only be cut very little a part of colon with a plane, must be a lot of segments with colon segmentation like this, wastes time and energy underaction; With after the virtual incision of colon three-dimensional structure being mapped to the process of two dimensional surface, can bring deformation to the anatomical structure on the colon inwall, influence diagnostic result.

Summary of the invention

The present invention is directed to the deficiency of designed scheme such as existing virtual endoscopic techniques and Joel G..Fletcher, a kind of visual method for virtual incising tubular organ has been proposed, in can not being subjected to, feasible diagnosis to colon spies on the restriction at angle, become directly perceived, quick, can not bring deformation again simultaneously the anatomical structure of colon inwall.

The present invention realizes by following technical method, the present invention at first is partitioned into the internal organs image from the primitive medicine data, again these pipeline internal organs are found out center path, determine to cut open the Surface Method vector for the every bit on the center path then, be radius of sphericity with this approximate distance of putting organ walls again, according to cuing open the Surface Method vector, with hemisphere part colon volume data is gathered subtraction, thereby the invalid part in the excision data, at last remaining volume data is carried out region growing, guarantee to be communicated with, show in interactively mode again.

The described internal organs image that is partitioned into from the primitive medicine data is found out center path to these pipeline internal organs again, is meant: cut apart for the primitive medicine data, the organic image that reconstructs is then found out center path to the whole pipe cavity again.

Describedly determine to cut open the Surface Method vector, be meant:, vertical with tangential direction by three condition: a. according to the tangential direction of every bit on the center path for the every bit on the center path; The angle that cuts direction of b. catching up with a center path point is the least possible; C. vector length is 1.Thereby what solve this point cuts open the Surface Method vector.

Described is radius of sphericity with this approximate distance of putting organ walls, is meant: every on the center path

Point is obtained its distance to organ walls on every side, and according to the form of wall this distance is increased processing, eliminates the influence of gauffer, and with this radius as spheroid in next step processing.

Described according to cuing open the Surface Method vector, with hemisphere the pipeline organ model is gathered subtraction, be meant: for each point on the center path, with this point is the center of circle, the approximate distance that previous step obtains is a radius, and it is last cuing open the determined direction of Surface Method vector, makes hemisphere, and deduct hemispheroidal pixel with the volumetric pixel of organ, hinder the part of observing thereby be equivalent to remove organ.

Described remaining model is carried out region growing, guarantee to be communicated with, be meant: carry out region growing for cutting the pixel that needs to keep among the result, and the connectedness of assurance results area, because cutting issuable fragment is not communicated with reserve area, thereby removed, obtain being convenient to the organ image of inspections and examinations.

The present invention is with respect to the advantage of prior art: 1, the visual angle is more flexible and open, makes diagnostic procedure more directly perceived.2, can remove ponding and other foreign material in the colon, make that diagnosis is more accurate.3, the visual angle can also move on to the colon outside, observe configuration and with the getting in touch of perienchyma's organ.

Description of drawings

Fig. 1 cavity viscera dummy cuts synoptic diagram

Embodiment

Below in conjunction with accompanying drawing one embodiment of the invention are elaborated: present embodiment is being to implement under the prerequisite with the technical solution of the present invention; provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

The present embodiment implementation step is as follows: (1) image segmentation.(2) find out center path.(3) determine to cut open the Surface Method vector.(4) determine cutting hemisphere.(5) utilize hemisphere cutting.(6) growth is communicated with.(7) draw also interactive the demonstration.

Embodiment adopts part prone position human colon Spiral CT scan data is handled, and implementation procedure is as follows:

1. utilize the method for region growing in the original CT scan image, to be partitioned into the binaryzation volume data of colon lumen, carry out the morphology dilation operation then, deduct the data of former cavity in the volume data after expansion again, thereby obtain the volume data of colon wall.

To cut apart and expand after colon binaryzation volume data, as the border, carry out range conversion with outer wall, utilize the inverse of range conversion value to make shortest path first again, obtain the center path of colon lumen.

3. to each point on the center path, determine that it cuts open the Surface Method vector.Make the Surface Method vector that cuts open of desired current center path point be

The unit tangent vector that points to next center path point is The Surface Method vector that cuts open of a last center path point is

Cut open the Surface Method vector

Satisfy following three constraint conditions:

Condition 1: vertical with unit tangent vector, also promptly:

\overset{&RightArrow;}{A} \cdot \overset{&RightArrow;}{Y} = 0

Condition 2: catch up with angle that cuts open the Surface Method vector the least possible (can be equivalent to tangent vector and last and cut open Surface Method vector coplane).Also promptly:

| \begin{matrix} a_{1} & a_{2} & a_{3} \\ x_{1} & x_{2} & x_{3} \\ y_{1} & y_{2} & y_{3} \end{matrix} | = 0

Condition 3: the length of cuing open the Surface Method vector is 1.Also promptly:

| | \overset{&RightArrow;}{Y} | | = \sqrt{y_{1}^{2} + y_{2}^{2} + y_{3}^{2}} = 1

4. to each point on the center path, determine cutting hemisphere.The centre of sphere is the center path point, and the hemisphere direction is with to cut open Surface Method vector consistent, and the radius of hemisphere is that the range conversion value of center path point adds 10.

5. the every bit on the center path utilizes the hemisphere of above-mentioned acquisition, and the colon volume data is cut.Also promptly in the colon wall volume data, with the zone of hemisphere process voxel as a setting all.

6. because the image bottom after handling has fragmentary fragment, therefore the volumetric pixel that colon top is kept partly carries out region growing, the part that can grow into is kept, the part that can not grow into is pixel as a setting, remove the fragment that incision brings with this, obtain being convenient to the organ image of inspections and examinations.

7. the part colon after the cutting is carried out volume drawing, show then, and allow any transformation angle, the colon inwall after cutting is observed.

As shown in Figure 1, be the synoptic diagram of virtual incision on two dimension.Through such processing, can remove ponding and other impurity of generally being in the below in the colon, and removed the colon of Lower Half, feasible observation visual angle to first half colon wall increases greatly, and it is more directly perceived and flexible, observation point can be more freely selected, and the tissue and the organ of colon outside can be watched.

Claims

1, a kind of visual method for virtual incising tubular organ, it is characterized in that, at first from the primitive medicine data, be partitioned into the internal organs image, again these pipeline internal organs are found out center path, determine to cut open the Surface Method vector for the every bit on the center path then, be radius of sphericity with this distance of putting organ walls again, according to cuing open the Surface Method vector, with hemisphere part colon volume data is gathered subtraction, thereby the invalid part in the excision data, at last remaining volume data is carried out region growing, guarantee to be communicated with, show in interactively mode again.

2, visual method for virtual incising tubular organ according to claim 1, it is characterized in that, the described internal organs image that from the primitive medicine data, is partitioned into, again these pipeline internal organs are found out center path, be meant: cut apart for the primitive medicine data, reconstruct the image of organ then, again the whole pipe cavity is found out center path.

3, visual method for virtual incising tubular organ according to claim 1 is characterized in that, describedly determines to cut open the Surface Method vector for the every bit on the center path, is meant: according to the tangential direction of every bit on the center path, by three conditions:

A. vertical with tangential direction;

The angle that cuts direction of b. catching up with a center path point is the least possible, promptly is equivalent to tangent vector and last one and cuts open Surface Method vector coplane:

|\begin{matrix} a_{1} & a_{2} & a_{3} \\ x_{1} & x_{2} & x_{3} \\ y_{1} & y_{2} & y_{3} \end{matrix}| = 0;

C. vector length is 1, thus solve this point cut open the Surface Method vector.

4, visual method for virtual incising tubular organ according to claim 1, it is characterized in that, described is radius of sphericity with this distance of putting organ walls, be meant: for the every bit on the center path, obtain its distance to organ walls on every side, and this distance is increased processing according to the form of wall, eliminate the influence of gauffer, and the radius of spheroid in handling as next step with this.

5, visual method for virtual incising tubular organ according to claim 1, it is characterized in that, describedly with hemisphere part colon volume data is gathered subtraction, be meant: for each point on the center path according to cuing open the Surface Method vector, with this point is the center of circle, the distance that previous step obtains is a radius, and it is last cuing open the determined direction of Surface Method vector, makes hemisphere, and deduct hemispheroidal pixel with the volumetric pixel of organ, hinder the part of observing thereby removed organ.

6, visual method for virtual incising tubular organ according to claim 1, it is characterized in that, described remaining volume data is carried out region growing, guarantee to be communicated with, be meant: carry out region growing for cutting the pixel that needs to keep among the result, and guarantee the connectedness of results area, because the fragment that cutting produces is not communicated with reserve area, thereby removed, obtain the organ image of being convenient to observe.