Eye parameter acquisition system based on 3D-MRI eyeball model

文档序号:1851965 发布日期:2021-11-19 浏览:19次 中文

阅读说明:本技术 一种基于3d-mri眼球模型的眼部参数获取系统 (Eye parameter acquisition system based on 3D-MRI eyeball model ) 是由 吕林 陈士达 赵秀娟 于 2021-08-25 设计创作,主要内容包括:本发明涉及眼部参数定位的技术领域,公开了一种基于3D-MRI眼球模型的眼部参数获取系统,包括模型构建模块,用于构建算法模型;眼球构建模块,用于构建3D-MRI眼球模型;初始参数获取模块,用于在3D-MRI眼球模型中找出初始眼球参数及其位置;数值输入模块,用于输入变量的数值;二次参数获取模块,用于获取在基于变量的数值上计算得到的二次眼球参数;处理模块,用于对获取的初始眼球参数和二次眼球参数进行处理,获取眼球参数之间的弧长和直线距离。本发明旨在通过眼球MRI数据,构建3D-MRI眼球模型,找出初始眼球参数及其位置,以便于获取二次眼球参数以及眼球参数之间的弧长和直线距离。(The invention relates to the technical field of eye parameter positioning, and discloses an eye parameter acquisition system based on a 3D-MRI eyeball model, which comprises a model construction module, a model acquisition module and a model acquisition module, wherein the model construction module is used for constructing an algorithm model; the eyeball construction module is used for constructing a 3D-MRI eyeball model; the initial parameter acquisition module is used for finding out initial eyeball parameters and positions thereof in the 3D-MRI eyeball model; the numerical value input module is used for inputting numerical values of the variables; the secondary parameter acquisition module is used for acquiring secondary eyeball parameters obtained by calculation on the numerical value based on the variables; and the processing module is used for processing the acquired initial eyeball parameters and the acquired secondary eyeball parameters to acquire the arc length and the linear distance between the eyeball parameters. The invention aims to construct a 3D-MRI eyeball model through eyeball MRI data, and find out initial eyeball parameters and positions thereof so as to obtain secondary eyeball parameters and arc lengths and linear distances among the eyeball parameters.)

1. An ocular parameter acquisition system based on a 3D-MRI eyeball model, characterized by comprising:

the model construction module is used for constructing an algorithm model;

the eyeball construction module is used for constructing a 3D-MRI eyeball model;

the initial parameter acquisition module is used for finding out initial eyeball parameters and positions thereof in the 3D-MRI eyeball model;

the numerical value input module is used for inputting numerical values of the variables;

the secondary parameter acquisition module is used for acquiring secondary eyeball parameters obtained by calculation on the numerical value based on the variables;

and the processing module is used for processing the acquired initial eyeball parameters and the acquired secondary eyeball parameters to acquire the arc length and the linear distance between the eyeball parameters.

2. The system of claim 1, wherein the model construction module comprises:

labeling unit: the method is used for marking an eyeball two-dimensional image area in a skull MRI image;

a training unit: the method is used for training the image labeled by the labeling unit so as to obtain an algorithm model capable of automatically identifying the eyeball two-dimensional image area from the skull MRI image.

3. The system of claim 1, wherein the eyeball building module comprises:

an entry unit: the head MRI image is used for inputting parameters to be acquired;

a model generation unit: used for reconstructing a 3D-MRI eyeball model corresponding to the skull MRI image.

4. The system for obtaining ocular parameters based on 3D-MRI eyeball model according to claim 1,

the initial parameter obtaining module obtains the initial eyeball parameters in the 3D-MRI eyeball model by distinguishing the front and back, the upper and lower, the temporo-side and the nasal side directions of the 3D-MRI eyeball model.

5. The system for obtaining ocular parameters based on 3D-MRI eyeball model according to claim 1,

the initial ocular parameters include at least a corneal center point (1), an optic nerve point (4), and the location and extent of the optic nerve portion and the posterior scleral staphyloma (7).

6. The system of claim 5, wherein the values of the variables include at least a corneal deviation value;

the secondary eyeball parameters at least comprise the positions of an eyeball upper positioning point (2) and an eyeball lower positioning point (3);

the positions of the eyeball upper positioning point (2) and the eyeball lower positioning point (3) are drawn into a cross arc line along the directions of the upper, lower, positive temporal side and nasal side of the 3D-MRI eyeball model by taking the corneal central point (1) as the center; and measuring the corneal deviation value along the crisscross arc in the up-down direction.

7. The system of claim 6, wherein the image processing device is further configured to acquire the parameters of the eye based on a 3D-MRI eyeball model,

the values of said variables also include the position (x, y) of the projected spot (5) of the macula on the outer surface of the sclera;

the position (x, y) of a projection point (5) of the macula lutea on the outer surface of the sclera is obtained through the position relation between the macula lutea and an optic nerve point (4);

the positional relationship between the macula lutea and the optic nerve point (4) is acquired by fundus images and OCT images.

8. The system of claim 7, wherein the image processing device is further configured to acquire the parameters of the eye based on a 3D-MRI eyeball model,

the position (x, y) of the projection point (5) of the macula lutea on the outer surface of the sclera is obtained by measuring the transverse distance x and the longitudinal distance y between the macula lutea and the optic nerve point (4) by taking the position point of the optic nerve point (4) as an origin, taking the direction of the temple side of the eyeball as an x axis, and taking the direction of the position of the fixed point (3) below the eyeball as a y axis.

9. The system of claim 7, wherein the image processing device is further configured to acquire the parameters of the eye based on a 3D-MRI eyeball model,

the values of the variables also include a nasal offset value z;

the secondary eyeball parameters also comprise an eyeball upper deviation point (2 ') and an eyeball lower deviation point (3');

the eyeball upper deviation point (2 ') and the eyeball lower deviation point (3') are obtained by taking an eyeball upper positioning point (2) and an eyeball lower positioning point (3) as initial points and deviating the nose side deviation value z towards the nose side direction.

10. The system of claim 9, wherein the image processing device is further configured to acquire the parameters of the eye based on a 3D-MRI eyeball model,

the straight-line distance between the eyeball parameters at least comprises the length of an axis of the eye;

the arc length between the eyeball parameters at least comprises the arc length of the upper belt and the lower belt in the initial state and the arc length of the upper belt and the lower belt after being pressed;

the length of the eye axis is the linear distance from a projection point (5) of the macula lutea on the outer surface of the sclera to a central point (1) of the cornea;

the arc length of the upper and lower belts of the girdle in the initial state is the arc length from a projection point (5) of the yellow spot on the outer surface of the sclera to an upper deviation point (2 ') of the eyeball and a lower deviation point (3') of the eyeball respectively;

the arc length of the upper and lower belts of the pressed pocket belt is determined according to the pressing height required by the eyeball, and the pressing height is determined by the length of the axis of the eye.

Technical Field

The invention relates to the technical field of eye parameter positioning, in particular to an eye parameter acquisition system based on a 3D-MRI eyeball model.

Background

At present, the three-dimensional reconstruction technology of orbital MRI and OCT images is already used for orbital diseases, preoperative evaluation of eye trauma and auxiliary surgical design, and plays a very important role in repairing orbital fractures in particular. For the MRI three-dimensional reconstruction technique of the eyeball, there are reports for identifying and classifying pathological myopic posterior scleral staphyloma, but there is no technique for performing accurate measurement of eyeball parameters, such as calculation of the axial length of the eye, horizontal diameter of the eyeball, vertical diameter and posterior scleral staphyloma configuration and range, and positioning of the macula lutea on the surface of the sclera, after the three-dimensional reconstruction of the eyeball based on the MRI.

On the other hand, the macular puccooh surgery has been proven to be effective in treating pathological myopia-induced posterior scleral staphyloma, macular hole, macular cleavage, macular detachment and other complications, but the surgery has not been effectively promoted, mainly because:

1) no method is available for accurately positioning the corresponding position of the extrabulbar macular;

2) the method for correctly calculating the top pressure height of the macular belt is not available;

3) different macular girdle materials have different designs and materials, and operators operate different materials, so that accurate positioning cannot be realized;

4) different sizes and forms of the posterior scleral staphyloma require different sizes of cuff materials, but the size of the posterior scleral staphyloma cannot be calculated or measured by the current method.

Disclosure of Invention

The present invention is directed to overcoming at least one of the above-mentioned drawbacks (disadvantages) of the prior art, and providing an eye parameter acquiring system based on a 3D-MRI eyeball model, which is used to solve the problem of accurate positioning of eye parameters.

In order to solve the technical problems, the invention adopts the technical scheme that:

an ocular parameter acquisition system based on a 3D-MRI eyeball model, comprising:

the model construction module is used for constructing an algorithm model;

the eyeball construction module is used for constructing a 3D-MRI eyeball model;

the initial parameter acquisition module is used for finding out initial eyeball parameters and positions thereof in the 3D-MRI eyeball model;

the numerical value input module is used for inputting numerical values of the variables;

the secondary parameter acquisition module is used for acquiring secondary eyeball parameters obtained by calculation on the numerical value based on the variables;

and the processing module is used for processing the acquired initial eyeball parameters and the acquired secondary eyeball parameters to acquire the arc length and the linear distance between the eyeball parameters.

In one embodiment, the model building module comprises:

labeling unit: the method is used for marking an eyeball two-dimensional image area in a skull MRI image;

a training unit: the method is used for training the image labeled by the labeling unit so as to obtain an algorithm model capable of automatically identifying the eyeball two-dimensional image area from the skull MRI image.

Specifically, the labeling unit may be labelme labeling software, and the eyeball two-dimensional images are labeled from the skull MRI images in batches, and then the obtained eyeball two-dimensional images are trained by the training unit, so that the algorithm model capable of automatically identifying the eyeballs from the skull MRI images is finally obtained.

Specifically, the cranial MRI image is a picture of the head in dicom format.

In the technical scheme, MRI refers to magnetic resonance imaging, and the invention scans skull images in a dicom format obtained by the skull through an MRI technology, thereby finding out images of eyeball parts in the skull images and finally constructing a 3D-MRI eyeball model. The parameters used for 3D-MRI shooting of the eyeball are as follows: the 3D-FIESTA sequence (a new fast imaging gradient echo sequence, a kind of water imaging) of the orbit MRI is adopted, the short TR and TE values are adopted, the phase loss degree caused by liquid flow is light, the high-ratio tissue signal of T2/T1 can be enhanced, and the obvious contrast with the tissues around the eyeball is formed, meanwhile, the 3D-FIESTA sequence of the orbit MRI can reduce the scanning layer thickness, thereby improving the spatial resolution of the tissues, and the MPR is utilized to carry out the recombination of any plane of the images. The 3D-FIESTA sequence of orbital MRI adopts thin layer scanning to know the deformation degree of the eyeball and measure the axis of the eye, the volume of the eyeball and the like. The parameters in specific application can be set as follows: TR 5.9ms, TE minim ms, echo sequence length 75, field of view 180 × 180, matrix set to 256 × 256, slice thickness 1mm, 0 pitch, voxel: 0.7x 0.7. The scan time was 7:06 minutes.

Wherein, TR is Time of Repetition, Repetition Time, generally referring to the Time interval between two consecutive radio frequency pulses; TE is time of Echo, Echo time, which refers to the time interval between the radio frequency pulse and the corresponding Echo; T2/T1 are two relaxation times, T1 is the time for the longitudinal magnetic vector to recover, and T2 is the decay and disappearance time for the transverse magnetic vector.

In one embodiment, the eyeball building module comprises:

an entry unit: the head MRI image is used for inputting parameters to be acquired;

a model generation unit: used for reconstructing a 3D-MRI eyeball model corresponding to the skull MRI image.

Specifically, the model generation module automatically identifies an eyeball two-dimensional image and an image of an optic nerve part in the skull MRI image through the algorithm model, and reconstructs an eyeball two-dimensional image mask into a 3D-MRI eyeball model through a MARCHING CUBE three-dimensional reconstruction algorithm.

Furthermore, the model generation unit calculates a pixel threshold of the eyeball part based on the image of the eyeball part, estimates a pixel range of the optic nerve by using the spatial characteristic that the optic nerve is close to the eyeball, and finds out the image of the optic nerve part, thereby constructing the 3D-MRI eyeball model with the optic nerve part.

Specifically, the spatial characteristic that the optic nerve is close to the eyeball means that the position of the optic nerve is adjacent to the position of the eyeball, so that when an image of the eyeball part is obtained, the position of the optic nerve can be found at the edge of the eyeball, the image of the optic nerve part is found, and a 3D-MRI eyeball model with the optic nerve part is constructed.

In one of the embodiments, the first and second electrodes are arranged in a circular shape,

the initial parameter obtaining module obtains the initial eyeball parameters in the 3D-MRI eyeball model by distinguishing the front and back, the upper and lower, the temporo-side and the nasal side directions of the 3D-MRI eyeball model.

In one of the embodiments, the first and second electrodes are arranged in a circular shape,

the initial ocular parameters include at least a corneal center point, an optic nerve point, and locations and ranges of an optic nerve portion and a posterior scleral staphyloma.

In one embodiment, the values of the variables include at least corneal deviation value;

the secondary eyeball parameters at least comprise positions of an eyeball upper positioning point and an eyeball lower positioning point;

the positions of the positioning point above the eyeball and the positioning point below the eyeball are crossed arcs along the upper, lower, positive temporal side and nasal side directions of the 3D-MRI eyeball model by taking the central point of the cornea as the center; and measuring the corneal deviation value along the crisscross arc in the up-down direction.

The corneal deviation value is measured along the positive temporal side and nasal side directions of the cross arc, and the positions of temporal side points and nasal side points can be obtained.

The straight line distance between the eyeball upper positioning point and the eyeball lower positioning point is the eyeball upper and lower diameters; the straight-line distance between the temporal point and the nasal point is the left and right diameters of the eyeball.

Further, the corneal deviation value is 18 mm.

In one of the embodiments, the first and second electrodes are arranged in a circular shape,

the values of the variables also include the location (x, y) of the projected spot of the macula on the outer surface of the sclera;

the position (x, y) of the projection point of the macula lutea on the outer surface of the sclera is obtained through the position relation between the macula lutea and the optic nerve point;

the positional relationship between the macula lutea and optic nerve points is acquired by fundus images and OCT images.

Among them, the fundus picture is preferably obtained by taking a single fundus photograph covering the posterior pole at 50 °.

The OCT picture is a posterior segment OCT picture and can be obtained by adopting a multi-line scanning mode crossing optic nerves and a macular region.

Because the actual position of the macula lutea is located in the eyeball and cannot be really displayed, the invention can obtain the actual distance between the macula lutea and the optic nerve point on the one hand through the fundus picture and the OCT picture; and on the other hand, the macula lutea is directly projected and positioned on the outer surface of the sclera, so that the projection point of the macula lutea on the outer surface of the sclera is obtained on the 3D-MRI eyeball model.

In one of the embodiments, the first and second electrodes are arranged in a circular shape,

the position (x, y) of the projection point of the macula lutea on the outer surface of the sclera is obtained by measuring the transverse distance x and the longitudinal distance y between the macula lutea and the optic nerve point by taking the position point of the optic nerve point as the origin, taking the direction of the temple side of the eyeball as the x axis, and taking the direction of the fixed point position below the eyeball as the y axis.

Further, the transverse distance x is a left and right deviation value of the belt, and is usually 1-6 mm; the longitudinal distance y is the upper and lower offset of the belt and is typically 1-6 mm. The left deviation value, the right deviation value, the upper deviation value and the lower deviation value of the girdle are calculated according to the actual horizontal distance and the vertical distance between the macula lutea and the optic nerve point in the fundus picture and the OCT picture.

Further, the difference value of the belt lengths of the upper belt and the lower belt of the pocket belt can be known through the upper deviation value and the lower deviation value of the pocket belt, and the difference value of the belt lengths of the upper belt and the lower belt of the pocket belt is the upper deviation value and the lower deviation value of the pocket belt.

In one of the embodiments, the first and second electrodes are arranged in a circular shape,

the values of the variables also include a nasal offset value z;

the secondary eyeball parameters also comprise the positions of the pocket belt connection points;

the pocket belt connecting points comprise temporal side fixing points, eyeball upper deviation points and eyeball lower deviation points;

the temporal side fixed point is obtained according to the temporal side belt length of the pocket belt and the position relation among the cornea center point, the optic nerve point and the temporal side fixed point;

the temporal zone length of the pocket zone is obtained according to the initial eyeball parameters, and is the arc length distance between an optic nerve point and a temporal fixed point;

the eyeball upper deviation point and the eyeball lower deviation point are obtained by taking an eyeball upper positioning point and an eyeball lower positioning point as initial points and deviating the nasal deviation value z towards the nasal side direction.

Further, the length of the temporal side of the girdle is obtained according to the disk type of the selected girdle. The model of the belt is selected according to the size of the scleral staphyloma, and the central position of the belt is the position of the projection point of the yellow spot on the outer surface of the sclera.

Further, the temporal side fixed point is obtained according to the arc length between the central point of the cornea and the temporal side fixed point; and the arc length between the central point of the cornea and the fixed point on the temporal side is obtained by subtracting the length of the temporal zone from the arc length from the central point of the cornea to the optic nerve point.

In this technical scheme, optic nerve also is located the inside of eyeball, and unable true demonstration, consequently can't directly measure optic nerve point to the arc length of temporal side fixed point through optic nerve point, consequently, this technical scheme subtracts the length of direct definite positive temporal side pocket area through the arc length of before-operation measurement cornea central point to optic nerve point, can calculate the arc length of cornea central point to temporal side fixed point to obtain the position of temporal side fixed point.

Wherein, contain titanium plate and the length scale mark of different circles combination in the pocket area temporal side area length, through determining which circle as temporal side fixed point, can obtain the length in positive temporal side pocket area.

For example: when the arc length from the optic nerve point to the central point of the cornea is 32mm and the belt length of the pocket belt on the positive temporal side is 14mm, the arc length from the central point of the cornea to the fixed point on the temporal side can be obtained by subtracting the belt length of the pocket belt on the positive temporal side from the arc length from the optic nerve point to the central point of the cornea, and the arc length from the central point of the cornea to the fixed point on the temporal side is 18mm, so that the position of the fixed point on the temporal side can be found.

Furthermore, because the positioning point above the eyeball and the positioning point below the eyeball are just positioned at the muscle stopping point, in order to avoid the muscle stopping point, the invention respectively deviates zmm towards the nasal side, thereby obtaining the deviation point above the eyeball and the deviation point below the eyeball. Preferably, the nasal offset value is 2 mm.

In one embodiment, the linear distance between the eyeball parameters at least comprises the length of the axis of the eye; the arc length between the eyeball parameters at least comprises the arc length of the upper belt and the lower belt in the initial state and the arc length of the upper belt and the lower belt after being pressed;

the arc length of the upper and lower belts of the pressed pocket belt is determined according to the pressing height required by the eyeball, and the pressing height is determined by the length of the axis of the eye.

Furthermore, the eye parameter acquiring system further comprises a storage module, which is used for generating a data list from the calculated eyeball parameters and the arc length and the straight line distance between the eyeball parameters, and displaying the data list on the two-dimensional eyeball image for reference.

The invention aims to construct a 3D-MRI eyeball model through eyeball MRI data, and eyeball parameters including the positions of various parameter points in the front-back, upper-lower, temporalis and nasal sides of an eyeball, the axial length of the eyeball, the front-back diameter of the eyeball, the upper-lower diameters of the eyeball, the left-right diameters of the eyeball, the position and the range of an optic nerve part, an optic nerve point and retroscleral staphyloma can be automatically measured and positioned through an automatic positioning technology, so that the placement position and the fixed position of a girdle and the pressing height of the girdle can be conveniently measured and calculated in the following process.

Compared with the prior art, the invention has the beneficial effects that:

the invention reconstructs an eyeball three-dimensional model based on eyeball MRI data, and realizes automatic measurement of various parameters of the eyeball through an automatic positioning system, wherein the parameters comprise the length of an axis of the eyeball, the front and back diameters of the eyeball, the left and right diameters of the eyeball, the upper and lower diameters of the eyeball, the pocket arc length of the eyeball, the size and range of the retroscleral staphyloma and the like.

The invention realizes the beneficial effects of positioning the projection point of the yellow spot on the surface of the sclera and directly displaying the positioning in the 3D model by combining the fundus picture and the OCT picture.

Drawings

Fig. 1 is a schematic structural diagram of an eyeball model according to the present invention.

Fig. 2 is a top view of the eyeball 3D model of the present invention.

Fig. 3 is a bottom view of the 3D eyeball model according to the present invention.

Fig. 4 is a schematic structural diagram of an eyeball 3D model optic nerve direction according to the present invention.

Fig. 5 is a schematic diagram of a position relationship between an eyeball displacement point and an eyeball positioning point of the eyeball 3D model according to the present invention.

Fig. 6 is a schematic diagram illustrating a positional relationship between an eyeball upper offset point and an eyeball lower offset point of the 3D eyeball model according to the present invention.

FIG. 7 is a schematic diagram illustrating a positional relationship between an eyeball upward deviation point and an eyeball downward deviation point on a plane according to the present invention.

Detailed Description

The drawings are only for purposes of illustration and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

As shown in fig. 1 to 7, the present embodiment discloses an eye parameter obtaining system based on a 3D-MRI eyeball model, including:

the model construction module is used for constructing an algorithm model;

the eyeball construction module is used for constructing a 3D-MRI eyeball model;

the initial parameter acquisition module is used for finding out initial eyeball parameters and positions thereof in the 3D-MRI eyeball model;

the numerical value input module is used for inputting numerical values of the variables;

the secondary parameter acquisition module is used for acquiring secondary eyeball parameters obtained by calculation on the numerical value based on the variables;

the processing module is used for processing the acquired initial eyeball parameters and the acquired secondary eyeball parameters to acquire arc length and linear distance between the eyeball parameters;

and the storage module is used for generating a data list from the calculated eyeball parameters and the arc length and the straight-line distance between the eyeball parameters and displaying the data list on the two-dimensional eyeball image for reference.

Specifically, the model building module comprises:

labeling unit: the method is used for marking an eyeball two-dimensional image area in a skull MRI image;

a training unit: the method is used for training the image labeled by the labeling unit so as to obtain an algorithm model capable of automatically identifying the eyeball two-dimensional image area from the skull MRI image.

Specifically, the labeling unit may be labelme labeling software, and the eyeball two-dimensional images are labeled from the skull MRI images in batches, and then the obtained eyeball two-dimensional images are trained by the training unit, so that the algorithm model capable of automatically identifying the eyeballs from the skull MRI images is finally obtained.

Specifically, the cranial MRI image is a picture of the head in dicom format.

In the technical scheme, MRI refers to magnetic resonance imaging, and the invention scans skull images in a dicom format obtained by the skull through an MRI technology, thereby finding out images of eyeball parts in the skull images and finally constructing a 3D-MRI eyeball model. The parameters used for 3D-MRI shooting of the eyeball are as follows: the 3D-FIESTA sequence (a new fast imaging gradient echo sequence, a kind of water imaging) of the orbit MRI is adopted, the short TR and TE values are adopted, the phase loss degree caused by liquid flow is light, the high-ratio tissue signal of T2/T1 can be enhanced, and the obvious contrast with the tissues around the eyeball is formed, meanwhile, the 3D-FIESTA sequence of the orbit MRI can reduce the scanning layer thickness, thereby improving the spatial resolution of the tissues, and the MPR is utilized to carry out the recombination of any plane of the images. The 3D-FIESTA sequence of orbital MRI adopts thin layer scanning to know the deformation degree of the eyeball and measure the axis of the eye, the volume of the eyeball and the like. The parameters in specific application can be set as follows: TR 5.9ms, TE minim ms, echo sequence length 75, field of view 180 × 180, matrix set to 256 × 256, slice thickness 1mm, 0 pitch, voxel: 0.7x 0.7. The scan time was 7:06 minutes.

Wherein, TR is Time of Repetition, Repetition Time, generally referring to the Time interval between two consecutive radio frequency pulses; TE is time of Echo, Echo time, which refers to the time interval between the radio frequency pulse and the corresponding Echo; T2/T1 are two relaxation times, T1 is the time for the longitudinal magnetic vector to recover, and T2 is the decay and disappearance time for the transverse magnetic vector.

In this embodiment, the eyeball building module includes:

an entry unit: the head MRI image is used for inputting parameters to be acquired;

a model generation unit: used for reconstructing a 3D-MRI eyeball model corresponding to the skull MRI image.

Specifically, the model generation module automatically identifies an eyeball two-dimensional image and an image of an optic nerve part in the skull MRI image through the algorithm model, and reconstructs an eyeball two-dimensional image mask into a 3D-MRI eyeball model through a MARCHING CUBE three-dimensional reconstruction algorithm.

Furthermore, the model generation unit calculates a pixel threshold of the eyeball part based on the image of the eyeball part, estimates a pixel range of the optic nerve by using the spatial characteristic that the optic nerve is close to the eyeball, and finds out the image of the optic nerve part, thereby constructing the 3D-MRI eyeball model with the optic nerve part.

Specifically, the spatial characteristic that the optic nerve is close to the eyeball means that the position of the optic nerve is adjacent to the position of the eyeball, so that when an image of the eyeball part is obtained, the position of the optic nerve can be found at the edge of the eyeball, the image of the optic nerve part is found, and a 3D-MRI eyeball model with the optic nerve part is constructed.

Further, the initial parameter obtaining module obtains the initial eyeball parameter in the 3D-MRI eyeball model by distinguishing the front and back, the upper and lower sides, the temporo side and the nasal side of the 3D-MRI eyeball model.

Specifically, the initial parameter acquisition module simulates a 3D-MRI eyeball model into a three-dimensional sphere by using a point cloud simulation technology, and finds out initial ocular parameters of the eyeball by distinguishing the front and back, upper and lower, temporo-temporal side and nasal side directions of the eyeball.

As shown in fig. 1, further, the initial eyeball parameters at least include a central corneal point 1, an optic nerve point 4, and the location and range of the optic nerve portion and the posterior scleral staphyloma.

In this embodiment, the values of the variables include at least corneal deviation value;

as shown in fig. 2 and fig. 3, the secondary eyeball parameters at least include positions of an eyeball upper positioning point 2 and an eyeball lower positioning point 3;

the positions of the eyeball upper positioning point 2 and the eyeball lower positioning point 3 are drawn with a cross arc line along the upper, lower, temporo side and nasal side directions of the 3D-MRI eyeball model by taking the cornea central point 1 as the center; and measuring the corneal deviation value along the crisscross arc in the up-down direction.

The corneal deviation value is measured along the positive temporal side and nasal side directions of the cross arc, and the positions of temporal side points and nasal side points can be obtained.

Wherein, the straight line distance between the eyeball upper positioning point 2 and the eyeball lower positioning point 3 is the eyeball upper and lower diameters; the straight-line distance between the temporal point and the nasal point is the left and right diameters of the eyeball.

Further, the corneal deviation value is 18 mm.

As shown in fig. 4, further, the values of the variables also include the position (x, y) of the projected spot 5 of the macula lutea on the outer surface of the sclera;

the position (x, y) of the projected spot 5 of the macula lutea on the outer surface of the sclera is obtained by the position relation between the macula lutea and the optic nerve point 4;

the positional relationship between the macula lutea and the optic nerve point 4 is acquired by fundus images and OCT images.

Among them, the fundus picture is preferably obtained by taking a single fundus photograph covering the posterior pole at 50 °.

The OCT picture is a posterior segment OCT picture and can be obtained by adopting a multi-line scanning mode crossing optic nerves and a macular region.

Because the actual position of the macula lutea is located in the eyeball and cannot be really displayed, the invention can obtain the actual distance between the macula lutea and the optic nerve point 4 on the one hand through the fundus picture and the OCT picture; and on the other hand, the macula lutea is directly projected and positioned on the outer surface of the sclera, so that a projection point 5 of the macula lutea on the outer surface of the sclera is obtained on the 3D-MRI eyeball model.

Specifically, the position (x, y) of the projected spot 5 of the macula lutea on the outer surface of the sclera is obtained by measuring the lateral distance x and the longitudinal distance y between the macula lutea and the optic nerve point 4 with the position point of the optic nerve point 4 as the origin, the anteroposterior direction of the eyeball as the x axis, and the direction of the position of the localization point 3 below the eyeball as the y axis.

Wherein, the transverse distance x is the left and right deviation value of the belt, and is usually 1-6 mm; the longitudinal distance y is the upper and lower offset of the belt and is typically 1-6 mm. The left and right deviation values of the girdle and the upper and lower deviation values of the girdle are calculated according to the actual horizontal distance and the vertical distance between the macula lutea and the optic nerve point 4 in the fundus picture and the OCT picture.

And the difference value of the belt lengths of the upper belt and the lower belt of the pocket belt can be known through the upper deviation value and the lower deviation value of the pocket belt, and the difference value of the belt lengths of the upper belt and the lower belt of the pocket belt is the upper deviation value and the lower deviation value of the pocket belt.

As shown in FIGS. 5-7, the values of the variables also include a nasal offset value z;

the secondary eyeball parameters also comprise the positions of the pocket belt connection points;

the pocket belt connecting points comprise temporal side fixing points 6, eyeball upper deviation points 2 'and eyeball lower deviation points 3';

the temporal fixing point 6 is obtained according to the temporal zone length of the pocket zone and the position relation among the cornea central point 1, the optic nerve point 4 and the temporal fixing point 6;

the temporal zone length of the pocket zone is obtained according to the initial eyeball parameters, and is the arc length distance between the optic nerve point 4 and the temporal fixed point 6;

the eyeball upper deviation point 2 'and the eyeball lower deviation point 3' are obtained by taking an eyeball upper positioning point 2 and an eyeball lower positioning point 3 as starting points and deviating the nose side deviation value z towards the nose side direction.

Further, the length of the temporal side of the girdle is obtained according to the disk type of the selected girdle. The model of the belt is selected according to the size of the scleral staphyloma, and the central position of the belt is the position of the macula lutea on the projection point 5 of the outer surface of the sclera.

Further, the temporal side fixed point 6 is obtained according to the arc length between the cornea central point 1 and the temporal side fixed point 6; and the arc length between the central point 1 of the cornea and the fixed point 6 on the temporal side is obtained by subtracting the length of the temporal zone from the arc length from the central point 1 of the cornea to the optic nerve point 4.

In this technical scheme, optic nerve also is located the inside of eyeball, can't truly show, consequently can't directly measure optic nerve point 4 through optic nerve point 4 to the arc length of temporal side fixed point 6, consequently, this technical scheme subtracts the length of the positive temporal side pocket area of direct definite through the arc length of measuring cornea central point 1 to optic nerve point 4 before the art, can calculate the arc length of cornea central point 1 to temporal side fixed point 6 to obtain the position of temporal side fixed point 6.

Wherein, contain titanium plate and the length scale mark of different circles combination in the pocket area temporal side area length, through determining which circle is as temporal side fixed point 6, can obtain the length in positive temporal side pocket area.

For example: when the arc length from the optic nerve point 4 to the cornea center point 1 is 32mm and the belt length of the pocket belt on the positive temporal side is 14mm, the arc length from the cornea center point 1 to the fixed point 6 on the temporal side can be obtained by subtracting the belt length of the pocket belt on the positive temporal side from the arc length from the optic nerve point 4 to the cornea center point 1, and therefore the position of the fixed point 6 on the temporal side can be found.

Furthermore, because the eyeball upper positioning point 2 and the eyeball lower positioning point 3 are just positioned at the muscle stopping points, in order to avoid the muscle stopping points, the invention respectively deviates zmm towards the nasal side, thereby obtaining the eyeball upper deviation point 2 'and the eyeball lower deviation point 3'. Preferably, the nasal offset value is 2 mm.

The straight-line distance between the eyeball parameters at least comprises the length of the axis of the eye; the arc length between the eyeball parameters at least comprises the arc length of the upper belt and the lower belt in the initial state and the arc length of the upper belt and the lower belt after being pressed;

the arc length of the upper and lower belts of the pressed pocket belt is determined according to the pressing height required by the eyeball, and the pressing height is determined by the length of the axis of the eye.

Specifically, in the technical scheme, the top pressure height, namely the height of the posterior scleral staphyloma 7 after being pressed, can be obtained by predicting the shortened length of the eye axis by combining the calculus principle.

Preferably, the height of the retroscleral staphyloma 7 pressed against the retroscleral staphyloma can be simulated through software, and the length of the upper and lower belts of the pressed belt can be obtained.

Furthermore, the pressed height of the posterior scleral staphyloma 7 is generally 1-4 mm.

Furthermore, the system for acquiring eye parameters of the present invention further comprises a storage module, configured to generate a data list from the calculated eyeball parameters and the arc length and the linear distance between the eyeball parameters, and display the data list on the two-dimensional eyeball image for reference.

The obtained data list is shown in the following table 1:

TABLE 1

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific embodiments of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention claims should be included in the protection scope of the present invention claims.

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