WO2016006633A1

WO2016006633A1 - Diagnosis device, diagnosis system, simulation method, and program

Info

Publication number: WO2016006633A1
Application number: PCT/JP2015/069666
Authority: WO
Inventors: 智憲岩崎
Original assignee: 国立大学法人鹿児島大学
Priority date: 2014-07-10
Filing date: 2015-07-08
Publication date: 2016-01-14
Also published as: JPWO2016006633A1; JP6579472B2

Abstract

According to the present invention, a model generation unit (12) uses a numerical analysis method to generate, on the basis of three-dimensional image data of the inside of a maxillofacial portion of a test subject, a three-dimensional shape model of the upper respiratory tract and tissues surrounding the upper respiratory tract, and a fluid model of air in the upper respiratory tract. A simulation execution unit (14) assigns unique physical property values to the three-dimensional shape model and fluid model generated by the model generation unit (12), and calculates information relating to the state of air passage in the upper respiratory tract, which varies in accordance with respiration, by carrying out a simulation of a fluid structure coupled analysis of the upper respiratory tract, surrounding tissues, and air inside the upper respiratory tract accompanying respiration of the test subject.

Description

[Correction based on Rule 91 28.08.2015] Airway ventilation state analysis system using fluid-structure interaction analysis of maxillofacial area

The present invention relates to a diagnostic apparatus, a diagnostic system, a simulation method, and a program.

Obstructive Sleep Apnea Syndrome (OSAS) is a respiratory disease that causes various respiratory effects by obstructing the upper respiratory tract during sleep and causing respiratory problems. Obstructive sleep apnea syndrome (hereinafter simply referred to as sleep apnea syndrome) is a cause of serious traffic accidents because it does not provide sufficient sleep at night and causes excessive sleepiness during the day. Attention has been paid.

A method for diagnosing sleep apnea syndrome has been proposed. For example, Non-Patent Document 1 discloses a method for diagnosing sleep apnea syndrome by constructing a fluid model of an upper airway on a computer based on a three-dimensional CT image and performing fluid analysis using the fluid model. Has been proposed. According to this method, based on the pressure distribution in the upper airway and the air velocity distribution, it is possible to narrow down the ventilation trouble site to some extent.

Sleep apnea syndrome is a disease that occurs relatively frequently. It is said that the frequency of adults with sleep apnea syndrome is 4%, and that of children is 2% from childhood to puberty regardless of age. Nevertheless, in sleep apnea syndrome, an effective method for identifying the causative site has not yet been established, and sufficient treatment results have not been obtained. The method proposed in Non-Patent Document 1 is a few effective methods for narrowing down the cause site of sleep apnea syndrome, but due to the following disadvantages, effective treatment results are not always obtained. .

(1) The simulation model of the upper airway is modeled as a rigid body that does not deform. For this reason, fluid analysis in consideration of elastic deformation of the upper airway is difficult. It is also difficult to reproduce the upper airway obstruction.

(2) Only the upper airway is modeled, and the tissue around the upper airway, which is often the root cause of sleep apnea syndrome, is not modeled. For this reason, the deformation of the tissue around the upper airway cannot be reproduced. For this reason, a person who makes a diagnosis can only estimate the root cause part indirectly from the analysis result of the fluid.

For example, the main cause of sleep apnea syndrome is narrowing of the upper respiratory tract due to tongue depression due to gravity in the supine position. However, in the technique disclosed in Non-Patent Document 1, the tongue, which is a tissue around the upper airway, is not modeled. For this reason, the narrowing of the upper airway due to the drop of the tongue due to gravity cannot be reproduced by simulation. Therefore, with this technique, it becomes difficult to specify that the cause of sleep apnea syndrome is narrowing of the upper respiratory tract due to tongue depression due to gravity in the supine position.

(3) The actual breathing aspect (periodic change of exhaled breathing) in which the air flow in the upper airway assumed in the fluid analysis using the simulation model is unidirectional and the air flow is bidirectional. Is different. For this reason, the flow of the fluid in the upper airway according to the actual aspect of breathing cannot be reproduced.

The present invention has been made to solve the above-described problems, and is a diagnostic device, a diagnostic system, a simulation method, and a program that can obtain better treatment results with respect to respiratory diseases more reliably. The purpose is to provide.

In order to achieve the above object, a diagnostic apparatus according to the first aspect of the present invention provides:
Using a numerical analysis technique, based on the three-dimensional image data inside the subject's maxillofacial portion, a three-dimensional shape model of the upper airway and tissues around the upper airway, and air fluid in the upper airway A model generation unit for generating a model;
A physical property value specific to the three-dimensional shape model and the fluid model generated by the model generation unit is given, and the upper airway, the surrounding tissue, and the air fluid in the upper airway accompanying the subject's breathing A simulation execution unit that calculates information on the ventilation state of the upper airway that fluctuates according to respiration by performing a simulation of structural coupling analysis;
Is provided.

In this case, a model display unit that displays a three-dimensional shape model of the upper airway and the surrounding tissue generated by the model generation unit;
A change unit for changing the three-dimensional shape of the three-dimensional shape model of the upper airway and the surrounding tissue displayed on the model display unit;
Further comprising
The simulation execution unit
By performing a simulation of the fluid-structure interaction analysis using the three-dimensional model of the upper airway and the surrounding tissue whose three-dimensional shape has been changed by the changing unit, information on the ventilation state of the upper airway is obtained. calculate,
It is good as well.

The three-dimensional model of the nasal cavity of the upper airway is a rigid body, and performs fluid analysis over one respiratory period to calculate information on the ventilation state of the nasal cavity, and at the boundary between the nasal cavity and the pharynx A fluid analysis unit for calculating a cross-sectional average pressure;
The simulation execution unit
Using the cross-sectional average pressure at the boundary between the nasal cavity and the pharynx over one respiratory cycle calculated by the fluid analysis unit as an initial condition, a model of the three-dimensional shape of the upper airway and the surrounding tissue excluding the nasal cavity is used. , By calculating a simulation of the fluid structure coupling analysis, to calculate information on the ventilation state of the upper airway,
It is good as well.

In addition, the simulation execution unit
In a state where the three-dimensional shape model of the surrounding tissue is deformed by gravity, the fluid-structure interaction analysis is performed, and information on the ventilation state of the upper airway is calculated.
It is good as well.

In addition, the simulation execution unit
As information on the ventilation state of the upper airway,
Calculating information on the flow of air in the upper airway or information on deformation of the upper airway and a region around the upper airway;
It is good as well.

In addition, the simulation execution unit
As information on the air flow in the upper airway,
Calculating pressure distribution or flow velocity distribution in the upper airway,
It is good as well.

In addition, a result display unit that displays information on the ventilation state of the upper airway calculated by the simulation execution unit,
It is good as well.

The diagnostic system according to the second aspect of the present invention is:
An imaging device for imaging three-dimensional image data inside the maxillofacial portion of the subject;
A diagnostic apparatus according to the present invention using the three-dimensional image data imaged by the imaging apparatus;
Is provided.

A simulation method according to the third aspect of the present invention provides:
A computer uses a numerical analysis method to calculate a model of a three-dimensional shape of the upper airway and a tissue around the upper airway based on the three-dimensional image data inside the maxillofacial portion of the subject, A model generation process for generating a fluid model of the air;
A computer gives specific physical property values to the three-dimensional shape model and the fluid model generated in the model generation step, and the upper airway, the surrounding tissue, and the upper airway associated with the subject's breathing A simulation execution step of calculating information on the ventilation state of the upper airway, which fluctuates according to breathing, by performing a simulation of fluid-structure interaction analysis of air;
Is provided.

A program according to the fourth aspect of the present invention is:
Computer
Using a numerical analysis method, based on the three-dimensional image data inside the subject's maxillofacial region, a model of the three-dimensional shape of the upper airway and the tissue around the upper airway, and the air in the upper airway A model generation unit for generating a fluid model;
A physical property value specific to the three-dimensional shape model and the fluid model generated by the model generation unit is given, and the upper airway, the surrounding tissue, and the air fluid in the upper airway accompanying the subject's breathing A simulation execution unit that calculates information on the ventilation state of the upper airway that fluctuates according to respiration by performing a simulation of structural coupling analysis;
To function as.

According to the present invention, simulation of fluid-structure interaction analysis is performed using a model of the three-dimensional shape of not only the upper airway but also the surrounding tissue. By this simulation, it is possible to calculate not only the flow of air in the upper airway accompanying breathing but also the deformation of the upper airway and surrounding tissues. Since the state of the upper airway and the surrounding tissue during actual sleep can be reproduced by simulation, the cause of the respiratory system disease can be more accurately identified. As a result, good treatment results can be obtained for respiratory diseases more reliably.

It is a block diagram which shows the schematic structure of the diagnostic system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the hardware constitutions of a computer. It is a figure which shows an example of the three-dimensional image of an upper airway, a tongue, and a soft palate. It is a figure which shows an example of the three-dimensional image of an upper airway, a tongue, a soft palate, and a bone. It is a figure which shows an example of the three-dimensional image of soft tissues, such as the muscle around a jaw. An example of a mesh model having a three-dimensional shape of an upper airway and a tissue around the upper airway is shown. It is a figure which shows an example of the three-dimensional image of an upper airway. It is a figure which shows an example of the cross-sectional average pressure in the boundary of the nasal cavity and pharynx over one respiration cycle. FIG. 9A is a diagram showing an example of a cross section of the upper airway when not lying on the back, and FIG. 9B is a diagram showing an example of a cross section of the upper airway when lying on the back. . An example of pressure distribution in the upper pharyngeal airway is shown by fluid-structure interaction analysis accompanying respiration. An example of the displacement distribution of the upper pharyngeal airway by the fluid-structure interaction analysis accompanying respiration is shown. It is a flowchart of a diagnostic process. It is a flowchart of a model production | generation process. It is a flowchart of a simulation execution process. It is a flowchart which shows the flow of the process of the simulation of fluid structure interaction analysis. It is a figure which shows typically the force which each element receives. It is a figure which shows the site | part used as treatment object. It is a block diagram which shows the schematic structure of the diagnostic system which concerns on Embodiment 2 of this invention. It is a figure which shows typically the structure around the upper airway and the upper airway before a change. It is a figure which shows typically the structure | tissue of the upper airway after change, and the upper airway.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG.
First, a first embodiment of the present invention will be described.

The diagnostic system 100 according to the first embodiment shown in FIG. 1 is used to reproduce on the computer the ventilation state of the upper respiratory tract of the human body that is the subject in order to identify the cause of sleep apnea syndrome. It is done. The diagnostic system 100 is based on the three-dimensional image data inside the subject's maxillofacial region acquired by an X-ray CT (Computer Tomography) device or the like in order to reproduce the ventilation state of the subject's upper airway. A model of a three-dimensional shape of the upper airway in the maxillofacial portion and a tissue around the upper airway and a fluid model of air in the upper airway are generated. The upper respiratory tract means from the nose to the nasal cavity, nasopharynx, pharynx, and larynx.

Furthermore, the diagnosis system 100 performs a simulation of fluid-structure interaction analysis using a three-dimensional shape model of the upper airway and the surrounding tissue of the upper airway and a fluid model of the air in the upper airway. The upper airway, the three-dimensional shape model of the surrounding tissue, and the fluid model of the air in the upper airway are given unique physical properties, and the simulation of fluid-structure interaction analysis makes the upper airway fluctuating according to respiration, It is possible to clarify the interaction between the surrounding tissue deformation and the air flow due to breathing in the upper airway. In addition, it is possible to accurately reproduce both the air flow (pressure distribution, flow velocity distribution) in the upper airway and the deformation of the upper airway due to the deformation of surrounding tissue during breathing. By reproducing these, the cause site of sleep apnea syndrome can be identified more accurately.

As shown in FIG. 1, the diagnostic system 100 includes an imaging device 1 and a computer 2. The imaging device 1 and the computer 2 are connected via a communication network. Through this communication network, data can be transmitted and received between the imaging apparatus 1 and the computer 2.

The imaging apparatus 1 is an X-ray CT apparatus. The imaging apparatus 1 captures a three-dimensional X-ray CT image of the subject's maxillofacial portion. The imaging device 1 includes an X-ray tube and a detector. When the X-ray CT scan is executed, X-rays irradiated from the X-ray tube and transmitted through the subject are detected by the detector. The detection result of the detector is stored in the imaging device 1 as raw data.

Further, the imaging apparatus 1 generates cross-sectional data (slice image data) of the maxillofacial portion of the subject by performing image reconstruction processing based on the stored raw data. Furthermore, the imaging device 1 generates three-dimensional image data inside the maxillofacial portion of the subject based on the slice image data. As described above, three-dimensional image data inside the maxillofacial portion of the subject is obtained. The obtained three-dimensional image data is transmitted to the computer 2 through the communication network as DICOM (Digital Imaging and Communications Communications in Medicine) data.

DICOM data refers to data generated based on the DICOM standard. The DICOM standard is mainly used as a format for medical image data. The DICOM data is composed of the three-dimensional image data and incidental information according to the DICOM standard. The incidental information is attribute information of image data such as patient information, imaging condition information, image information, and display information, and is embedded as tag information in DICOM data.

The computer 2 generates a model of a three-dimensional shape of the upper airway in the maxillofacial portion of the subject and the tissue around the upper airway based on the three-dimensional X-ray CT image data included in the received DICOM data. This model is generated based on the finite element method. This model is generated by dividing an object into a finite number of elements bounded by nodes. That is, the generated upper airway and the tissue model around the upper airway are so-called mesh models configured by joining a plurality of elements in a mesh shape at nodes. The element may be divided on the basis of voxel data constituting the medical image data.

Furthermore, the computer 2 gives unique physical property values to the mesh model of the three-dimensional shape of the tissue around the upper airway and its maxillofacial surface, and performs a fluid-structure interaction analysis simulation accompanying the breathing of the subject, Get information about the ventilation status of the upper airway.

FIG. 2 shows the hardware configuration of the computer 2 in FIG. As shown in FIG. 2, the computer 2 includes a control unit 31, a main storage unit 32, an external storage unit 33, an operation unit 34, a display unit 35, and a communication unit 36. The main storage unit 32, the external storage unit 33, the operation unit 34, the display unit 35, and the communication unit 36 are all connected to the control unit 31 via the internal bus 30.

The control unit 31 includes a CPU (Central Processing Unit) and the like. The CPU executes the program 39 stored in the external storage unit 33, thereby realizing each component of the computer 2 shown in FIG.

The main storage unit 32 is composed of RAM (Random-Access Memory) or the like. The main storage unit 32 is loaded with a program 39 stored in the external storage unit 33. In addition, the main storage unit 32 is used as a work area (temporary data storage area) of the control unit 31.

The external storage unit 33 includes a non-volatile memory such as a flash memory, a hard disk, a DVD-RAM (Digital Versatile Disc Random-Access Memory), a DVD-RW (Digital Versatile Disc ReWritable). In the external storage unit 33, a program 39 to be executed by the control unit 31 is stored in advance. Further, the external storage unit 33 supplies data used when executing the program 39 to the control unit 31 in accordance with an instruction from the control unit 31, and stores the data supplied from the control unit 31.

The operation unit 34 includes a pointing device such as a keyboard and a mouse, and an interface device that connects the keyboard and the pointing device to the internal bus 30. Information regarding the content operated by the operator is input to the control unit 31 via the operation unit 34.

The display unit 35 includes a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), an organic EL (ElectroLuminescence), or the like. When the operator inputs operation information, an operation screen is displayed on the display unit 35. Further, as will be described later, information related to the ventilation state of the upper airway of the subject is displayed on the display unit 35.

The communication unit 36 includes a serial interface or a parallel interface. The communication unit 36 is connected to the imaging device 1 via the communication network and receives the 3D X-ray CT image data transmitted from the imaging device 1.

1 includes a control unit 31, a main storage unit 32, an external storage unit 33, an operation unit 34, a display unit 35, a communication unit 36, etc. as hardware resources. It demonstrates its function by being used as a.

As shown in FIG. 1, the computer 2 having a hardware configuration as shown in FIG. 2 has a storage unit 10, a data acquisition unit 11, a model generation unit 12, a fluid analysis unit 13, A simulation execution unit 14 and an output unit 15 are provided.

The storage unit 10 corresponds to the external storage unit 33 in FIG. 2 in the hardware configuration shown in FIG. The storage unit 10 stores various data. One of the data stored by the storage unit 10 is DICOM data 21.

The data acquisition unit 11 corresponds to the control unit 31 and the communication unit 36 in the hardware configuration shown in FIG. The data acquisition unit 11 receives the three-dimensional X-ray CT image data (DICOM data) of the maxillofacial portion transmitted from the imaging device 1. The data acquisition unit 11 stores the received DICOM data 21 in the storage unit 10.

The model generation unit 12 corresponds to the control unit 31 in the hardware configuration illustrated in FIG. The model generation unit 12 inputs DICOM data 21 stored in the storage unit 10, that is, three-dimensional image data inside the subject's maxillofacial portion. Based on the DICOM data 21, the model generation unit 12 generates a three-dimensional shape model of the upper airway and the tissue around the upper airway and a fluid model of air in the upper airway using the finite element method.

The three-dimensional shape model of the upper airway and the tissues around the upper airway is constructed based on the governing equations indicating the structure and shape deformation of each tissue. Tissues around the upper respiratory tract include soft tissues such as bones, tongue, soft palate, and maxillofacial muscles.

The fluid model is constructed based on a fluid governing equation (for example, Bernoulli's equation, Naviestoke's equation, etc.) using information on the air flow such as the pressure and flow velocity of the fluid as variables.

FIG. 3 shows an example of a three-dimensional image of the upper airway, tongue, and soft palate. A1 is the upper airway, A2 is the soft palate, and A3 is the tongue. As shown in FIG. 3, the tongue A3 and the soft palate A2 are tissues around the upper airway adjacent to the upper airway A1. The tongue A3 is known as the main cause of sleep apnea syndrome. This is because the tongue A3 falls down and squeezes the upper airway when sleeping in the supine position.

FIG. 4 shows a three-dimensional image of bone in addition to the upper airway, soft palate, and tongue. A4 is a bone. As shown in FIG. 4, the mandible and cervical vertebrae exist around the upper airway, tongue, and soft palate. For the mandible and cervical vertebra, their three-dimensional shape models are generated as tissues around the upper airway.

FIG. 5 shows an example of a three-dimensional image of soft tissues such as muscles and fat around the jaw. For such soft tissue around the jaw, a three-dimensional shape model is generated as tissue around the upper airway. This is because enlargement of the soft tissue around the jaw greatly affects respiration.

FIG. 6 shows an example of a three-dimensional mesh model of soft tissue portions around the upper airway, tongue, soft palate, bone, and jaw. In these three-dimensional shape models, nodes connecting elements are common on the boundary surface of each tissue. For this reason, the upper airway and its surrounding area are formed so as to be regarded as one three-dimensional shape model. In this way, it is possible to reproduce, by the three-dimensional shape model, how the adjacent tissues are deformed due to the deformation of each tissue.

The model generation unit 12 generates a three-dimensional model by dividing the upper airway into a nasal cavity portion and a portion below the pharynx. The nasal cavity portion is generated as STL (Standard （Triangulated Language) data. The STL data is data representing three points of a triangular patch used to approximate a solid, and the object surface is represented as a polygon by triangular patches (facets).

FIG. 7 shows an example of a three-dimensional image of the upper airway. In FIG. 7, the part above the line L is the nasal cavity part. Here, the portion above the line L is stored in the storage unit 10 as the nasal cavity portion STL data 22.

The model generation unit 12 generates a three-dimensional mesh model for the upper respiratory tract below the pharynx. The generated three-dimensional mesh model of the upper airway below the pharynx and the three-dimensional mesh models of other tissues are stored in the storage unit 10 as the three-dimensional shape model data 23.

The fluid analysis unit 13 corresponds to the control unit 31 in the hardware configuration illustrated in FIG. The fluid analysis unit 13 uses the nasal cavity portion STL data 22 to perform a fluid analysis over one respiratory cycle with the nasal cavity as a rigid body, and calculates information regarding the ventilation state of the nasal cavity. This is because the internal structure of the nasal cavity is complicated, there is almost no change in the shape of the airway, and fluid-structure interaction analysis is difficult. As information about the calculated ventilation state of the nasal cavity, for example, there is a pressure distribution in the nasal cavity.

The fluid analysis unit 13 calculates the cross-sectional average pressure P (t) at the boundary between the nasal cavity and the pharynx based on the pressure distribution in the nasal cavity. FIG. 8 shows an example of the cross-sectional average pressure P (t) at the boundary between the nasal cavity and the pharynx over one respiratory cycle. As shown in FIG. 8, the cross-sectional average pressure P (t) repeats exhalation and inspiration with a period T. In expiration, air in the nasal cavity is positive with respect to the external pressure, and in inspiration, air in the nasal cavity is in negative pressure with respect to the external pressure.

The simulation execution unit 14 corresponds to the control unit 31 in the hardware configuration illustrated in FIG. The simulation execution unit 14 gives specific physical property values to the three-dimensional shape model and the fluid model generated by the model generation unit 12, and the upper airway, surrounding tissues, and air fluid in the upper airway accompanying the subject's breathing By performing a simulation of the structural coupling analysis, information on the ventilation state of the upper airway that varies with breathing is calculated.

The fluid structure coupled analysis simulation is a numerical analysis simulation for analyzing a phenomenon in which a solid structure is deformed by a force exerted by a fluid flow. Sleep apnea syndrome is often the root cause of tissue surrounding the upper respiratory tract. For this reason, if the simulation of fluid-structure interaction analysis including the tissues around the upper airway is performed to reproduce the deformation of the tissues around the upper airway during sleep, the cause of sleep apnea syndrome Can be identified more accurately.

Specific physical property values of the three-dimensional shape model include Young's modulus, linear expansion coefficient, Poisson's ratio, shear elastic modulus, etc. of each tissue. For fluid, the viscosity coefficient of air, density, bulk modulus, Reynolds number, etc. is there. As these physical property values, those stored in the storage unit 10 as the physical property value data 25 are used. As the physical property values, those known as the physical property values of the tissue may be used, but those measured for each subject may be used.

The simulation execution unit 14 uses a calculated cross-sectional average pressure P (t) at the boundary between the nasal cavity and the pharynx over one respiratory cycle as an initial condition, and generates a three-dimensional mesh model of the upper airway excluding the nasal cavity and surrounding tissues. It is used to simulate the fluid-structure interaction analysis of the upper respiratory tract and surrounding tissues associated with the subject's breathing.

The simulation execution unit 14 performs a simulation of fluid-structure interaction analysis of the upper airway and the surrounding tissue that accompanies the subject's breathing in a state where the three-dimensional model of the surrounding tissue is deformed by gravity.

FIG. 9A shows an example of a cross section of the upper airway when not lying on the back, and FIG. 9B shows an example of a cross section of the upper airway when lying on the back. ing. As can be seen by comparing FIG. 9A and FIG. 9B, the upper airway is narrower when lying on its back. This is because the tongue part is sunk by gravity and compresses the upper airway.

As described above, the simulation execution unit 14 performs the simulation of the fluid structure coupled analysis in consideration of the gravity. Therefore, the ventilation of the upper airway is accurately reproduced while the upper airway deforming according to the posture of the subject is accurately reproduced. The state can be calculated.

The simulation execution unit 14 calculates information regarding the air flow in the upper airway and the deformation state of the upper airway and the three-dimensional shape model of the tissue around the upper airway. The simulation execution unit 14 calculates the pressure distribution in the upper airway, the flow velocity distribution, or the displacement distribution of the three-dimensional shape model of the tissue around the upper airway and the upper airway as information on the air flow in the upper airway. These pieces of information are stored in the storage unit 10 as simulation result data 26.

The output unit 15 corresponds to the control unit 31 and the display unit 35 in the hardware configuration of FIG. The output unit 15 displays the pressure distribution in the upper airway, the flow velocity distribution, or the deformation state of the upper airway.

FIG. 10 shows an example of the pressure distribution in the pharyngeal airway part by the fluid structure coupled analysis accompanying respiration. Further, FIG. 11 shows an example of the displacement distribution of the upper pharyngeal airway portion by the fluid structure coupled analysis accompanying respiration. In FIG. 10, the higher the pressure is, the darker the color is displayed. In FIG. 11, the larger the displacement is, the darker the color is displayed. In the pressure distribution shown in FIG. 10, the pressure on the upper airway is higher. Further, in the displacement distribution shown in FIG. 11, there is no place where the displacement is locally increased.

The output unit 15 can also display and output the upper airway deformed by the fluid-structure interaction analysis and the three-dimensional shape of the tissue around the upper airway.

Next, the flow of diagnostic processing by the diagnostic system 100 will be described. As shown in FIG. 12, first, an imaging process is performed in the imaging apparatus 1 (step S1). In this imaging step, three-dimensional image data inside the subject's maxillofacial portion is obtained. The three-dimensional image data is sent to the computer 2 and stored in the storage unit 10 of the computer 2 as DICOM data 21 by the data acquisition unit 11.

Subsequently, the computer 2 performs a model generation process (step S2). In the model generation step, as shown in FIG. 13, the model generation unit 12 performs the three-dimensional analysis of the upper airway and surrounding tissues based on the three-dimensional image data (DICOM data 21) inside the subject's maxillofacial portion. A shape model and a fluid model in the upper airway are generated, and the data of the generated fluid model is stored in the storage unit 10 as the three-dimensional shape model data 23 (step S21). Here, the model generation unit 12 generates the three-dimensional model of the nasal cavity part and the three-dimensional model of the part other than the nasal cavity for the upper airway separately. Subsequently, the model generation unit 12 generates STL data of the nasal cavity portion and stores it as the nasal cavity portion STL data 22 in the storage unit 10 (step S22).

Subsequently, the fluid analysis unit 13 performs a fluid analysis of the nasal cavity part based on the nasal cavity part STL data 22, calculates the pressure distribution in the nasal cavity, and stores it in the storage unit 10 as the intranasal pressure distribution data 24 ( Step S23). The fluid analysis is performed on the assumption that the nasal cavity portion is rigid and does not deform. The fluid analysis unit 13 calculates an average cross-sectional pressure P (t) between the nasal cavity and the pharynx based on the pressure distribution obtained by the fluid analysis, and also includes it in the intranasal pressure distribution data 24 to store it. 10 (step S24).

Returning to FIG. 12, subsequently, the computer 2 performs a simulation execution process (step S3). In the simulation execution step, as shown in FIG. 14, the simulation execution unit 14 refers to the physical property value data 25 stored in the storage unit 10, and sets the physical property values of the upper airway and surrounding tissues to the respective three-dimensional shape models. (Step S31).

For example, for the three-dimensional shape model of the upper respiratory tract below the pharynx, physical properties such as Young's modulus and Poisson's ratio specific to each tissue are set in the three-dimensional shape model. For example, the physical property value of the tongue is set for the three-dimensional shape model of the tongue, the physical property value of the soft palate is set for the three-dimensional shape model of the soft palate, and the physical property value of the bone is set for the three-dimensional shape model of the bone. For the three-dimensional shape model of the soft tissue around the jaw, the physical property value of the soft tissue is set.

Subsequently, the simulation execution unit 14 sets the direction of gravity (step S32). This setting is performed by an operation input from the operation unit 34. For example, when diagnosing the ventilation state of the upper airway in the supine position, the occipital side of the subject is set as the lower side.

Subsequently, the simulation executing unit 14 performs a fluid structure coupled analysis simulation (step S33). The simulation is performed in a state where the three-dimensional shape model of the upper airway and surrounding tissue and the fluid model of the upper airway are integrated.

In this simulation, the average cross-sectional pressure P (t) between the nasal cavity and pharynx in the upper airway is used as an initial condition. Then, the fluid analysis that analyzes the air flow in the upper airway and the structural analysis that analyzes the deformation of the upper airway and the surrounding tissue take into account the mutual effects of the three-dimensional shape model and the fluid model. The pressure distribution, flow velocity distribution, and upper airway displacement distribution in the upper airway in one breath are calculated.

FIG. 15 shows the flow of the simulation process of the fluid structure interaction analysis performed in step S33. First, the simulation execution unit 14 performs a gravity calculation so that the three-dimensional shape model of the surrounding tissue is deformed (step S41). In this state, the three-dimensional shape model including the upper airway and surrounding tissues is in the state shown in FIG.

FIG. 16 schematically shows the upper airway in the supine position and the tissue around the upper airway. As shown in FIG. 16, when the subject is lying on his / her back, the upper airway A1 is vertically sandwiched between the tongue A3 and the lower bone A4. Furthermore, due to the drop of the tongue A3 due to the gravity G, the upper airway A1 is deformed and becomes narrower than the awake state.

15, the simulation execution unit 14 first performs a fluid analysis of the fluid model A5 in the upper airway A1 to obtain the pressure P in the upper airway (step S42). Here, the simulation execution part 14 calculates | requires the load conditions to the inner wall surface (boundary surface) of upper airway A5 based on the pressure P (refer FIG. 16) calculated | required by the fluid analysis.

Subsequently, the simulation execution unit 14 performs structural analysis of the upper airway A1 and surrounding tissue using the load condition as a boundary condition, and the displacement of the inner wall surface of the upper airway in a state where the gravity G and the pressure P are balanced (for example, , [Delta] x in FIG. 16 and the like are obtained (step S43). The simulation execution unit 14 updates the three-dimensional shape of the model of the upper airway and the tissue around the upper airway based on the displacement of the inner wall surface obtained by the structural analysis.

Subsequently, the simulation execution unit 14 determines whether or not the termination condition is satisfied (step S44). The end condition may be that the load condition and the displacement of the wall surface converge within an allowable range.

If the termination condition is not satisfied (step S44; No), the simulation executing unit 14 performs a fluid analysis based on the inner wall surface displaced by the structural analysis (step S42). In this way, steps S41 → S42 are repeated. By repeating this, the load condition (pressure P) and the displacement (Δx) of the inner wall surface converge to constant values.

As shown in FIG. 16, a negative pressure P is generated in the upper airway during breathing and in the inspiratory phase. This negative pressure P further narrows the upper airway and displaces the boundary surface. In this simulation, the final load that converged within the allowable range of each boundary element was repeatedly performed by fluid analysis using the fluid model in the upper airway and structural analysis using the model of the upper airway and surrounding tissue. A set of conditions (pressure P) and displacement (Δx) of the inner wall surface is obtained as pressure distribution and displacement distribution in the upper airway.

When the pressure P in the upper airway and the gravity G are in a balanced state and the end condition is satisfied (step S44; Yes), the simulation executing unit 14 ends the simulation and stores the simulation result in the storage unit 10 (step S45). Thereby, the simulation of the fluid structure interaction analysis is completed. The simulation result data 26 stored in the storage unit 10 includes the pressure distribution in the upper airway, the displacement distribution of the upper airway, and the deformed three-dimensional shape of the tissue around the upper airway when the termination condition is satisfied. It is data.

14, the output unit 15 displays and outputs the simulation result (step S34). As a result, the display unit 35 displays a pressure distribution and a flow velocity distribution in the upper airway, a deformed three-dimensional model of the tissue around the upper airway, and the like.

Referring to the simulation result displayed on the output unit 15, it is possible to know the pressure distribution during breathing in the upper airway of the subject, the deformation of the upper airway, the deformation of surrounding tissues, and the like. Based on these pieces of information, it is possible to detect which part of the upper airway is constricted. If the upper airway is narrowed, it is easy to identify the cause of sleep apnea syndrome.

As described above, the output unit 15 can display the deformation of the three-dimensional shape of the tissue model around the upper airway along with the pressure distribution in the upper airway or the displacement distribution of the upper airway. In this way, it becomes possible to more accurately identify which part of the surrounding tissue is causing the stenosis in the upper airway.

For example, as shown in FIG. 17, when the pressure is extremely high at B1, the nasal cavity is considered as a cause of sleep apnea syndrome. Such as nasal congestion and nasal catarrh. In this case, the site to be treated is the nose.

In addition, when the pressure is extremely high in B2, adenoid is considered as a cause of sleep apnea syndrome. In this case, excision of adenoids is an appropriate treatment method.

Also, when the pressure is extremely high at B3, the tonsils of the palate are considered as the cause of sleep apnea syndrome. In this case, the site to be treated is the soft palate.

When the pressure is extremely high at B4, the jaw is considered to be a cause of sleep apnea syndrome. In this case, the site to be treated is the lower jaw. Correction or weight loss of the upper teeth and lower teeth is the main treatment method.

Also, the cause of sleep apnea syndrome is not always one. Of the parts B1 to B4 shown in FIG. 17, a plurality of parts may be the cause part. If the simulation of the fluid-structure interaction analysis according to this embodiment is performed, it is easy to find out that a plurality of parts cause sleep apnea syndrome.

As described in detail above, according to this embodiment, simulation of fluid-structure interaction analysis is performed using a model of a three-dimensional shape of not only the upper airway but also the surrounding tissue. By this analysis, it is possible to calculate not only the flow of air in the upper airway accompanying breathing but also the deformation of the upper airway and surrounding tissues. Since the state of the upper airway and the surrounding tissue during actual sleep can be reproduced by simulation, the cause of the respiratory system disease can be more accurately identified. As a result, good treatment results for respiratory diseases can be obtained more reliably.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described.

The diagnostic system according to Embodiment 2 of the present invention is used for planning a treatment plan for sleep apnea syndrome, which is a respiratory disease.

As shown in FIG. 18, in the diagnostic system 100 according to this embodiment, the output unit 15 displays and outputs the three-dimensional shape model of the upper airway generated by the model generation unit 12 and the tissue around the upper airway. In addition, the computer 2 is different from the first embodiment in that the changing unit 16 is provided.

The output unit 15 displays and outputs the upper airway and the tissue around the copper based on the nasal cavity portion STL data 22 and the three-dimensional shape model data 23 stored in the storage unit 10 in response to the operation input.

The user operates the operation unit 34 (for example, by operating the mouse) while looking at the 3D model of the upper airway displayed on the output unit 15 and the tissue around the upper airway (for example, by operating the mouse). Specify an area. The operation input input from the operation unit 34 is input to the control unit 31, and the control unit 31 performs processing according to the operation input. This processing corresponds to the changing unit 16 in FIG.

For example, it is assumed that an area D shown in FIG. 19 is designated as a specific area by an operation input from the operation unit 34. In this case, the change unit 16 changes the three-dimensional shape mesh model of the upper airway and the tissue around the upper airway so as to cut out the designated region D according to the operation input of the operation unit 34. The output unit 15 displays the three-dimensional shape mesh model of the changed upper airway and the tissue around the upper airway. Thus, the changing unit 16 changes the three-dimensional mesh model of the upper airway and the tissue around the upper airway according to the operation input.

FIG. 20 shows the upper airway after excision of the designated region D and the tissue around the upper airway. The changed three-dimensional model is stored in the storage unit 10 as the three-dimensional shape model data 23. When the changed region D is the nasal cavity part, the STL data of the changed nasal cavity part is stored in the storage unit 10 as the nasal cavity part STL data 22.

After the change by the changing unit 16 is completed, the simulation executing unit 14 uses the three-dimensional shape mesh model of the upper airway and the tissue around the upper airway edited by the changing unit 16 and stored in the storage unit 10. The fluid structure coupled analysis of the upper airway associated with breathing and the tissue surrounding the upper airway is simulated to calculate information on the air flow in the upper airway and information on the deformation of the upper airway. The calculated simulation result is stored in the storage unit 10 as simulation result data 26 and is displayed and output by the output unit 15. With reference to this information, it is possible to check the ventilation state of the upper airway after the designated area D is deleted.

As described above in detail, according to this embodiment, the fluid-structure interaction analysis is simulated using the model of the three-dimensional shape of the upper airway changed by the changing unit 16 and the surrounding tissue. By this simulation, it is possible to predict information about the ventilation state of the upper airway after treatment. If it is possible to predict the upper respiratory tract and the surrounding tissue during sleep after surgery by simulation, the optimal amount of tissue resection can be obtained before surgery, and an appropriate treatment plan can be established. Can stand. As a result, good treatment results for respiratory diseases can be obtained more reliably.

As mentioned above, the cause of sleep apnea syndrome may not be one. In this case, the diagnosis system 100 according to this embodiment is used to change the three-dimensional shape of each tissue suspected as a causal site and perform simulation to analyze how the ventilation state of the upper airway changes. By doing so, it is also possible to accurately specify a complex cause site.

There are no particular restrictions on the subject according to each of the above embodiments. Both children and adults can diagnose and treat sleep apnea syndrome. Childhood sleep apnea syndrome has a profound effect on growth. Sleep apnea syndrome is also said to have an incidence of over 50% in children with Down syndrome. For this reason, identification of the exact cause site of sleep apnea syndrome has great benefits for society. If the cause of sleep apnea syndrome can be accurately identified, medical costs can be greatly reduced, and serious accidents can be prevented in advance, reducing economic loss and making it safer. A society can be realized.

In each of the above embodiments, the fluid-structure interaction analysis was performed using a weakly coupled method (time difference method). However, the strongly coupled method (integrated solution) solves the governing equations of the fluid and the structure exactly at the same time. For example, fluid-structure interaction analysis may be performed. As described above, the simulation method of the fluid-structure interaction analysis is not limited to the above-described method, and various methods can be applied.

In each of the embodiments described above, the finite element method is used to generate the three-dimensional shape model of the upper airway and the tissue around the upper airway and the fluid model of the air in the upper airway. Absent. For example, in addition to the finite element method, using a numerical analysis method such as a finite difference method, a boundary element method, a finite volume method, etc., a three-dimensional shape model of the upper airway and the tissue around the upper airway, An air fluid model may be generated.

In each of the above embodiments, the imaging apparatus 1 and the X-ray CT apparatus are used, but the present invention is not limited to this. An MRI (Magnetic Resonance Imaging) apparatus or an ultrasonic diagnostic apparatus may be used as the imaging apparatus 1. Furthermore, one 3D image data is generated from a plurality of 3D image data obtained from an X-ray CT apparatus, an MRI apparatus, and an ultrasonic diagnostic apparatus, and a model of a 3D shape of each tissue is generated from the generated image data. You may make it produce | generate.

In each of the above embodiments, the case where the sleep apnea syndrome is diagnosed and treated has been described, but the present invention is not limited to this. An evaluation system can be used for diagnosis and treatment as long as it is a respiratory disease and is related to the shape of the upper respiratory tract. The present invention can also be used to identify the cause of symptoms such as hypertension.

In addition, the hardware configuration and software configuration of the computer 2 are merely examples, and can be arbitrarily changed and modified.

The central part that performs processing of the computer 2 composed of the control unit 31, the main storage unit 32, the external storage unit 33, the operation unit 34, the display unit 35, the communication unit 36, the internal bus 30, and the like is a dedicated system Regardless, it can be realized using a normal computer system. For example, a computer program for executing the above operation is stored and distributed in a computer-readable recording medium (flexible disk, CD-ROM, DVD-ROM, etc.), and the computer program is installed in the computer. Thus, the computer 2 that executes the above-described processing may be configured. Further, the computer 2 may be configured by storing the computer program in a storage device included in a server device on a communication network such as the Internet and downloading it by a normal computer system.

When the functions of the computer 2 are realized by sharing an OS (operating system) and an application program or by cooperation between the OS and the application program, only the application program portion may be stored in a recording medium or a storage device. .

It is also possible to superimpose a computer program on a carrier wave and distribute it via a communication network. For example, the computer program may be posted on a bulletin board (BBS, “Bulletin” Board System) on the communication network, and the computer program may be distributed via the network. The computer program may be started and executed in the same manner as other application programs under the control of the OS, so that the above-described processing may be executed.

The present invention is capable of various embodiments and modifications without departing from the broad spirit and scope of the present invention. The above-described embodiments are for explaining the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

The present application claims priority based on Japanese Patent Application No. 2014-142076 filed on July 10, 2014, and the specification of Japanese Patent Application No. 2014-142076 is included in this specification. The claims and the entire drawing are incorporated by reference.

1 imaging device, 2 computer, 10 storage unit, 11 data acquisition unit, 12 model generation unit, 13 fluid analysis unit, 14 simulation execution unit, 15 output unit, 16 change unit, 21 DICOM data, 22 nasal cavity part STL data, 23 3D shape model data, 24 nasal pressure distribution data, 25 physical property value data, 26 simulation result data, 30 internal bus, 31 control unit, 32 main storage unit, 33 external storage unit, 34 operation unit, 35 display unit, 36 Communication department, 39 program, 100 diagnostic system.

Claims

Using a numerical analysis technique, based on the three-dimensional image data inside the subject's maxillofacial portion, a three-dimensional shape model of the upper airway and tissues around the upper airway, and air fluid in the upper airway A model generation unit for generating a model;
A physical property value specific to the three-dimensional shape model and the fluid model generated by the model generation unit is given, and the upper airway, the surrounding tissue, and the air fluid in the upper airway accompanying the subject's breathing A simulation execution unit that calculates information on the ventilation state of the upper airway that fluctuates according to respiration by performing a simulation of structural coupling analysis;
A diagnostic device comprising:
A model display unit for displaying a three-dimensional shape model of the upper airway and the surrounding tissue generated by the model generation unit;
A change unit for changing the three-dimensional shape of the three-dimensional shape model of the upper airway and the surrounding tissue displayed on the model display unit;
Further comprising
The simulation execution unit
By performing a simulation of the fluid-structure interaction analysis using the three-dimensional model of the upper airway and the surrounding tissue whose three-dimensional shape has been changed by the changing unit, information on the ventilation state of the upper airway is obtained. calculate,
The diagnostic device according to claim 1.
The model of the three-dimensional shape of the nasal cavity of the upper airway is a rigid body, and fluid analysis over one respiratory cycle is performed to calculate information on the ventilation state of the nasal cavity, and the cross-sectional average at the boundary between the nasal cavity and the pharynx A fluid analysis unit for calculating pressure;
The simulation execution unit
Using the cross-sectional average pressure at the boundary between the nasal cavity and the pharynx over one respiratory cycle calculated by the fluid analysis unit as an initial condition, a model of the three-dimensional shape of the upper airway and the surrounding tissue excluding the nasal cavity is used. , By calculating a simulation of the fluid structure coupling analysis, to calculate information on the ventilation state of the upper airway,
The diagnostic device according to claim 1 or 2.
The simulation execution unit
In a state where the three-dimensional shape model of the surrounding tissue is deformed by gravity, the fluid-structure interaction analysis is performed, and information on the ventilation state of the upper airway is calculated.
The diagnostic device according to any one of claims 1 to 3.
The simulation execution unit
As information on the ventilation state of the upper airway,
Calculating information on the flow of air in the upper airway or information on deformation of the upper airway and a region around the upper airway;
The diagnostic device according to any one of claims 1 to 4.
The simulation execution unit
As information on the air flow in the upper airway,
Calculating pressure distribution or flow velocity distribution in the upper airway,
The diagnostic device according to claim 5.
A result display unit for displaying information on the ventilation state of the upper airway calculated by the simulation execution unit;
The diagnostic device according to any one of claims 1 to 6.
An imaging device for imaging three-dimensional image data inside the maxillofacial portion of the subject;
The diagnostic apparatus according to any one of claims 1 to 7, wherein the three-dimensional image data captured by the imaging apparatus is used.
A diagnostic system comprising:
A computer uses a numerical analysis method to calculate a model of a three-dimensional shape of the upper airway and a tissue around the upper airway based on the three-dimensional image data inside the maxillofacial portion of the subject, A model generation process for generating a fluid model of the air;
A computer gives specific physical property values to the three-dimensional shape model and the fluid model generated in the model generation step, and the upper airway, the surrounding tissue, and the upper airway associated with the subject's breathing A simulation execution step of calculating information on the ventilation state of the upper airway, which fluctuates according to breathing, by performing a simulation of fluid-structure interaction analysis of air;
A simulation method comprising:
Computer
Using a numerical analysis method, based on the three-dimensional image data inside the subject's maxillofacial region, a model of the three-dimensional shape of the upper airway and the tissue around the upper airway, and the air in the upper airway A model generation unit for generating a fluid model;
A physical property value specific to the three-dimensional shape model and the fluid model generated by the model generation unit is given, and the upper airway, the surrounding tissue, and the air fluid in the upper airway accompanying the subject's breathing A simulation execution unit that calculates information on the ventilation state of the upper airway that fluctuates according to respiration by performing a simulation of structural coupling analysis;
Program to function as.