WO2019109575A1 - 基于个体特征的经颅脑图谱生成方法、导航方法及其系统 - Google Patents

基于个体特征的经颅脑图谱生成方法、导航方法及其系统 Download PDF

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WO2019109575A1
WO2019109575A1 PCT/CN2018/084000 CN2018084000W WO2019109575A1 WO 2019109575 A1 WO2019109575 A1 WO 2019109575A1 CN 2018084000 W CN2018084000 W CN 2018084000W WO 2019109575 A1 WO2019109575 A1 WO 2019109575A1
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transcranial
scalp
brain
map
individual
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French (fr)
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朱朝喆
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北京师范大学
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Publication of WO2019109575A1 publication Critical patent/WO2019109575A1/zh

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T19/00—Manipulating 3D models or images for computer graphics
    • A—HUMAN NECESSITIES
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    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/40—Detecting, measuring or recording for evaluating the nervous system
    • A61B5/4058—Detecting, measuring or recording for evaluating the nervous system for evaluating the central nervous system
    • A61B5/4064—Evaluating the brain
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    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
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    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
    • G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
    • G06F3/03545—Pens or stylus
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    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
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    • G06T7/143—Segmentation; Edge detection involving probabilistic approaches, e.g. Markov random field [MRF] modelling
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/02—Operational features
    • A61B2560/0223—Operational features of calibration, e.g. protocols for calibrating sensors
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    • G06—COMPUTING; CALCULATING OR COUNTING
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Definitions

  • the invention relates to an individual transcranial brain map generation method, and relates to a transcranial brain map navigation method based on individual characteristics, and relates to a corresponding individual transcranial brain map navigation system, belonging to the technical field of cognitive neuroscience.
  • Functional brain imaging represented by functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS), enables neuroscience researchers to observe the function of living human brains in a non-invasive manner.
  • fMRI functional magnetic resonance imaging
  • fNIRS functional near-infrared spectroscopy
  • Transcranial brain mapping techniques including transcranial brain therapy and transcranial brain imaging, have been rapidly evolving and have shown great potential in brain mechanism assessment and brain injury treatment.
  • Transcranial Magnetic Stimulation achieves inhibition or excitation of local brain activity at high spatial and temporal resolutions by externally applied magnetic fields.
  • the non-invasive nature of transcranial magnetic stimulation makes it useful to assess the causal relationship between specific brain regions/brain circuits and behavior.
  • Transcranial magnetic stimulation is also widely used to treat various neuropsychiatric disorders such as Parkinson's disease, pain, addiction, and the like. It is worth mentioning that transcranial magnetic stimulation has been certified by the US Food and Drug Administration (FDA) as a clinical intervention for the treatment of drug-resistant depression.
  • FDA US Food and Drug Administration
  • Transcranial mapping techniques are typically performed on the visible scalp surface (referred to as the operating space).
  • the target area of transcranial treatment and transcranial brain imaging is located inside the brain (called the utility space), which is invisible from the outside from the operator's perspective. Therefore, it is very difficult to locate an optimal imaging or stimulation site on the surface of an individual's scalp given a certain brain region label in the target location or utility space. This can lead to suboptimal, inconsistent experimental results, and even conflicting conclusions.
  • inconsistent placement of coils that perform transcranial magnetic stimulation on a target area for treating depression eg, the dorsal prefrontal cortex
  • the placement of the fNIRS photopole is also critical.
  • Improper placement may result in deviations in the recorded cortical position and may even cover the wrong cortical area.
  • the separation between the visible operating space (scalp surface) and the invisible utility space (inside the brain) is still one of the biggest challenges in effectively and accurately applying these transcranial mapping techniques.
  • the first technical problem to be solved by the present invention is to provide a method for generating an individual's transcranial brain map.
  • Another technical problem to be solved by the present invention is to provide a transcranial brain map navigation method based on individual characteristics.
  • Yet another technical problem to be solved by the present invention is to provide an individual transcranial map navigation system.
  • a method for generating a craniofacial coordinate system based on an individual feature includes the following steps:
  • the longitude curve can be uniquely determined as the intersection curve between the surface of the scalp and the plane passing through AL, AR and p, and p' is the intersection between the equator of the skull and the longitude curve;
  • L Nz-p' is the length of the curve from Nz to p' of the equator of the skull
  • L e is the full length of the equator of the skull
  • L AL-p is the longitude curve of L AL-p-AR along the entire length The length of the curve from AL to p.
  • the craniofacial coordinate system generating method further comprises the step (15): establishing a CPC space on the standard hemisphere; and planarizing the hemisphere with CPC coordinates using a Hammer-Aitoff projection to generate a flat ellipse.
  • a method for generating a transcranial brain map based on individual characteristics includes the following steps:
  • the step (2) comprises the following sub-steps:
  • a transcranial brain map navigation method based on individual characteristics including the following steps:
  • the sampling point comprises two parts, the first part is four skull marks Nz, Iz, AL and AR, and the second part is manually collected by the operator on the surface of the scalp of the subject. .
  • the discrete point cloud generated based on the sampling point is represented in the nose-to-ear pre-coordinate system; wherein the origin O of the nose-to-ear coordinate system is defined at the midpoint of the AL-AR connection.
  • the direction from the O point to the Nz is the positive direction of the X axis
  • the direction from the O point to the AL is the positive direction of the Y axis
  • the positive direction of the Z axis is defined in the cross direction of the XY axis.
  • the CRUST algorithm is used to reconstruct the topological connection between the discrete point clouds to obtain a triangular patch set TP ⁇ (i,j,k)
  • i,j,k 1,2,...M ⁇ ; where i, j, k are the numbers of the points in P, respectively, and each triple (i, j, k) represents three points having topological neighbors.
  • i 1, 2,3,...,N DP ⁇ , as The approximate curved surface.
  • an individual transcranial map navigation system including a processing component, a display component, a memory, a three-dimensional positioning component, and an input/output interface;
  • the processing component is respectively connected to the three-dimensional positioning component, the display component, the memory, and the input and output interface, for performing all or part of the steps in the above-described transcranial map navigation method;
  • the display component is coupled to the three-dimensional positioning component for real-time display of the current state of the three-dimensional positioning component on the surface of the scalp of the subject and the state in the transcranial map;
  • the memory is configured to store various types of data
  • the three-dimensional positioning component is configured to reconstruct an approximate curved surface of the surface of the scalp of the subject by using a plurality of points collected from the surface of the scalp of the subject;
  • the input/output interface is configured to implement connection between the individual transcranial map navigation system and an external transcranial device.
  • the three-dimensional positioning component is a Fastrak magnetic field three-dimensional locator, comprising a magnetic field emitter and two magnetic field detectors; one of the magnetic field detectors is in the shape of a probe, and the other magnetic field detector is in the shape of a cube.
  • the magnetic field emitter is fixed on a bracket behind the subject, and the cubic magnetic field detector is fixed on the subject's tibia, and the shape of the probe is The magnetic field detector was held by the experimenter and calibrated on the surface of the subject's scalp.
  • the present invention firstly provides an individual method for generating a transcranial brain map, which can project invisible map information in the brain onto the visible surface of the scalp, so that the originally separated operation space and utility space are merged. Together.
  • the present invention further provides an individual transcranial map navigation system for the problem of applying a transcranial map to an individualized placement that directs transcranial devices.
  • the experimental results show that the invention can effectively improve the coverage accuracy of the brain region of the near-infrared measurement photopole and the consistency of the measurement positions in different human epithelial layers, thereby improving the sensitivity of the near-infrared detection task to induce brain activity.
  • 1(a) to 1(e) are schematic views of a series of embodiments of a transcranial brain map
  • FIG. 2 is a schematic diagram of identifying a skull mark from a magnetic resonance image
  • Figure 3 is a schematic diagram of a CPC coordinate system
  • Figure 4 shows a schematic diagram of the probability of a single CPC coordinate point through the brain mapping
  • FIG. 5 is a diagram showing an example of the structure of an individual transcranial brain map navigation system provided by the present invention.
  • Figure 6 is a schematic diagram showing the spatial position and attitude of the magnetic field detector under the reference frame of the magnetic field emitter.
  • FIG. 7 is a schematic diagram showing spatial transformation of a physical coordinate system to a head coordinate system
  • Figure 8 is a schematic view of a nose-to-ear coordinate system
  • Figure 9 is a schematic diagram of the scalp surface reconstruction process, where a shows 21 unstructured scatters collected on the scalp surface, b shows the topological relationship of the sample points calculated by the CRUST algorithm, and c shows the reconstructed point cloud obtained by the spheroidization process. ;
  • FIG. 10 is a schematic diagram of the use state of the individual transcranial map navigation system provided by the present invention, wherein a is a screenshot displayed by the display component, and b is a schematic diagram of the actual operation performed by the experimenter.
  • the transcranial map is a brain map based on the surface of the scalp that projects invisible information in the brain onto the visible surface of the scalp (especially the upper surface of the scalp), allowing researchers or physicians to directly use these brains. Atlas information on structure and brain function.
  • the present invention first explicitly constructs a standard skull coordinate system for quantitative description of the surface space of different individual skulls. Then, based on the assumption that the cranial-brain correspondence is consistent in the population, a correspondence between the standard skull surface space and the standard brain space where the brain map is located is established. Finally, the present invention solves the correspondence between the skull surface space-brain partition label space from the correspondence between the skull surface space-standard brain space and the standard brain space-brain partition label space provided by the brain map. As a result, the present invention reversely presents information in the corresponding brain standard space and brain map to the skull coordinate system, thereby forming a novel "transcranial brain map".
  • the transcranial map is essentially a map of brain function built on the surface of the coordinated scalp, that is, in a coordinate brain space, the traditional brain map corresponds to each brain position and its function or anatomical label, thus The various cortical locations and their corresponding map labels accessible by the brain mapping technique are depicted and presented explicitly on the surface of the scalp as a visible operating space.
  • the transcranial brain map can map the prior brain partition information in the traditional brain map to the skull space for the transcranial brain imaging device in the sense of the population level cranial-brain correspondence. Therefore, it can be seen as an extension of the traditional brain map in the field of transcranial brain imaging technology.
  • the location of the transcranial data in the brain space can be transformed into the location of the transcranial imaging device in the skull space, which makes real-time localization of the transcranial mapping technique possible.
  • the label information of the transcranial brain map is displayed in the space of the skull, this characteristic is very advantageous for superimposing the transcranial brain map on the surface of the individual scalp for display, thereby guiding the transcranial imaging device on the surface of the skull of the subject in an intuitive manner. Place. Therefore, the establishment of the transcranial brain map solves the contradiction between the separation of the operating space and the utility space in the transcranial brain mapping technique.
  • FIG. 1(a) to 1(e) are schematic views of a series of embodiments of a transcranial brain map.
  • a uniform craniofacial coordinate system is defined on the surface of the scalp, which describes all possible positions of the probe that can be set by the brain mapping technique, and the probe is placed on a given skull.
  • Position the location of the black dot in the picture.
  • a probe placed on the surface of its scalp will be able to detect a specific cortical location/brain region (where the yellow dot is located).
  • this cranial-brain correspondence may not be determined given the differences in anatomical structures between individuals.
  • this probability correspondence provides the probability of accessing the population level of each brain region from the skull position and uses it as a priori knowledge.
  • the transcranial map is essentially a mapping of the prior knowledge of the entire brain space defined for the craniofacial coordinate system. Specifically, in the series of embodiments shown in FIG. 1, if the most likely target brain partition label and its associated probability are considered for each skull position, the maximum likelihood label map as shown in FIG. 1(d) ( MLM) and the maximum probability map (MPM) as shown in Figure 1(e) can serve as a useful guide for probe alignment through transcranial mapping techniques.
  • the process of generating the transcranial map mainly comprises three steps: 1) creating a craniofacial coordinate system at the individual level; 2) establishing a transcranial mapping system for connecting the position of the skull with the position of the brain; A three-step stochastic process in a Markov chain is used to construct a transcranial brain map.
  • the craniofacial coordinate system needs to meet two basic requirements: first, it should provide a one-to-one mapping of the individual scalp surface; second, for the convenience of group-level research, for each position in the craniofacial coordinate system, The position of the underlying cortex from different individuals is substantially identical in neuroanatomy.
  • CPC coordinate system The basic idea of the CPC coordinate system is to construct a coordinate system similar to the latitude and longitude lines on the surface of the scalp. Unlike the geographic latitude and longitude system, the CPC coordinate system determines the "latitude and longitude" by means of two surface scale measurements.
  • a two-dimensional proportional coordinate system called a continuous proportional coordinate space (abbreviated as CPC space) is established on the scalp surface of an individual by the following three steps:
  • Identify at least five skull markers Nz, Iz, AL, AR and Cz from the 10-20 system on the scalp surface of the navie space See Figure 3(a)). See Figure 2 for an example of identifying a skull marker in a magnetic resonance image, where Iz is the outer occipital bulge of the human skull to which the trapezius muscle is attached; AL and AR are the anterior points of the left and right ears, identified as tragus The peak region; Nz is determined as the depression position in the upper part of the bridge of the nose; Cz is determined as the intersection of the cranial surface geodesic line AL-Cz-AR and Nz-Cz-Iz, and the two cranial surface geodesics are equally divided.
  • the skull equator is defined as the intersection curve between the surface of the scalp and the plane passing through Nz, Cz and Iz (ie curve 1 in Figure 3(a));
  • the longitude curve (ie curve 2 in Figure 3(a)) can be uniquely determined as the intersection curve between the surface of the scalp and the plane passing through AL, AR and p, p' is The intersection between the equator of the skull and the longitude curve.
  • any point p of the upper scalp (higher than the curve specified by Nz, Iz, AL, AR points) can be uniquely determined by a pair of non-negative real numbers (p e , p l ):
  • L Nz-p' is the length of the curve along the Nz to p' of the skull equator
  • L e is the full length of the skull equator (from Nz to Iz)
  • L AL-p is along the full length
  • L AL-p The length of the longitude curve of -AR from AL to p.
  • the surface position of the p-point as an arbitrary point is uniquely represented by the ratio of p' and p to the two curves, respectively, and the calculation formula is shown in the formula (1) and the formula (2).
  • Fig. 3(b) is a schematic diagram of a two-dimensional proportional coordinate system (abbreviated as CPC coordinate system) established on the surface of the scalp.
  • the two-dimensional proportional coordinate system provides a one-to-one mapping of any point p on the surface of the scalp to the CPC space.
  • the CPC coordinate system essentially constructs a coordinate system similar to the latitude and longitude lines on the surface of the scalp. However, unlike the geographic latitude and longitude lines, the determination of "latitude and longitude" by the CPC coordinate system is determined by means of two surface ratio measurements.
  • a reasonable anatomy can be established on the scalp surface of the individual level based on the correspondence between the skull markers (Nz, Iz, AL, AR and Cz) and the proportional relationship defined by the CPC coordinate system (proportional to scale and shape). Learn the correspondence.
  • a special CPC space is created on the standard hemisphere.
  • the hemisphere with the CPC coordinate system is planarized using the existing Hammer-Aitoff projection to generate a map of the CPC coordinate system presented on the flat ellipse, which the applicant calls the Beijing Normal University Map ( See Figure 3(d)), which is essentially a two-dimensional projected image of a standard CPC coordinate system.
  • any brain function data related to the scalp surface can be presented on the map, enabling effective comparisons between different projects, populations, laboratories, and even different imaging modalities.
  • TBM Transcranial brain mapping
  • the bottom layer corresponding to any point p of a given scalp surface can be determined in an individual space (eg, an individual 3D MRI image).
  • Cortical position c After all cortical locations are spatially normalized to standard brain space (ie, MNI space), all (p, c) pairs are aggregated to produce a deterministic individual transcranial mapping model. Then, by integrating all individual transcranial mapping models to generate a probabilistic transcranial mapping model at the population level:
  • C is a subset of the standard brain space and contains all cortical locations associated with the brain mapping technique. Probability through the brain mapping model gives the probability of each targeted cortical position c(x, y, z) when stimulating or recording from any point p(p e , p l ) on the scalp surface of a given coordinate.
  • Figure 4 shows the probability transcranial mapping model corresponding to a single CPC coordinate.
  • P (0.4, 0.6)
  • the corresponding point B can be determined on the scalp surface of each individual level, and the corresponding position of the cortical projection point C is determined using a mature balloon expansion model.
  • the magnetic resonance image space on the individual level is identified.
  • a mapping from a point in the skull space to a label in the label space can be seen as a two-step mapping. First, it is mapped from the skull space S to the brain space B, and then from the brain space B to the label space L. Since the two-step mapping is a probability mapping, this process can also be seen as a two-step stochastic process. Since the correspondence between brain space and brain partition labels is determined by the structural laws of the human brain itself, we assume that for any point in the brain coordinate space, the probability of corresponding to each brain region label is determined, and the previous skull coordinate space It is irrelevant to the corresponding path in the brain coordinate space. Therefore, this two-step stochastic process has Markov properties.
  • brain maps are constructed in a probabilistic framework.
  • the basic relationship described by a traditional brain map eg, MNI map
  • B is a subset of the standard brain space and contains all possible brain tissue points in the brain template of the map; l ⁇ L, L contains all possible map labels, each Each of the map labels represents a specific brain region in the brain map.
  • b) represents the probability that a map number l appears at position b in the human brain.
  • the basic relationship described by the brain map is also a conditional probability:
  • a transcranial map can be constructed by a two-step stochastic process in a Markov chain. Specifically, the first step: the given point p(p e , p l ) as an input is mapped to the cortical position c(x, y, z) in the standard brain space by the probability transcranial mapping P(c
  • the two-step stochastic process uses a Markov chain commonly used by those skilled in the art.
  • p) can be used in P(c
  • b) to calculate.
  • the Chapman-Kolmogorov equation represents:
  • the transcranial brain map constructed by the above steps is a probability map, that is, when the probe is stimulated or recorded at any position of the scalp surface of a given coordinate, the brain can be given a mark by l. The probability that each targeted brain region is explored. It projects the invisible map information of the brain onto the visible scalp, allowing researchers or doctors to directly use these brain structures and functional map information, greatly improving the role of brain maps in transcranial mapping techniques.
  • the present invention first provides a theoretical framework based on a two-step Markov chain model as a transcranial brain map.
  • the first step is the cranio-cortical mapping from the scalp position in the CPC space to the underlined cortical position in the MNI space.
  • the second step is to construct a transcranial brain map using a traditional brain map, essentially a mapping from the cortical location of the MNI space to the map label space.
  • the present invention provides a scalable transcranial brain model using a probabilistic framework, and the brain map used in the second step above can be replaced by any other brain map.
  • transcranial brain map Although only three macroscopic anatomical brain maps (BA map, AAL map and LPBA map) are provided for constructing a transcranial brain map in the present invention, similar functional maps, connection maps, and other maps can be A transcranial brain map used to provide functionality for a specific application.
  • transcranial brain imaging technology a primary problem faced by transcranial brain imaging technology is how to locate the functional information obtained by the measurement of the skull bone into the brain map, that is, the transcranial positioning problem.
  • transcranial devices including transcranial imaging devices or transcranial therapeutic devices
  • another aspect of the problem of transcranial brain imaging technology is how to use the anatomical information in the brain map to guide the individualized placement of transcranial devices, ie transcranial navigation problems.
  • the overall solution of the present invention is as follows: First, a standardized coordinate system is constructed in the skull space visible by the transcranial device to quantitatively describe the entire cranial space covered by the entire transcranial technique. Then, based on the large sample structure image data, the corresponding relationship at the crowd level is solved from the cranial space to the standard brain space and the cranial space to the brain map label space. In this way, the problems of both transcranial positioning and transcranial navigation are solved. This will be explained in detail below.
  • the location of the transcranial data in the brain space can be transformed into the location of the transcranial device in the skull space, which makes real-time localization of the transcranial mapping technique possible.
  • this feature is very useful for superimposing the transcranial brain map on the surface of the individual scalp for display, thereby guiding the transcranial device on the surface of the scalp of the subject in an intuitive manner. Place.
  • the present invention provides a surface reconstruction technique based on sparse sampling points, and on the basis of the automatic realization of the skull coordinate system.
  • Location Algorithm can reconstruct the approximate surface of the scalp surface of the subject only by sparse uniform sampling of dozens of points on the surface of the scalp of the subject, and realize the reconstruction of the individual CPC coordinate system of the subject on the curved surface.
  • the present invention proposes an individual transcranial map navigation system based on a skull coordinate system and a transcranial brain map.
  • the system can realize the real-time positioning function of the magnetic field three-dimensional locator, and transform the position of the probe surface of the subject's scalp in real time into the CPC coordinate system of the transcranial brain map, thereby realizing the transcranial brain map and physics of the computational space.
  • the fusion of the surface of the scalp of the subject in the space thereby using the information of the transcranial brain map to guide the placement of the transcranial device on the surface of the scalp.
  • the individual transcranial map navigation system at least includes a processing component, a display component, a memory, a three-dimensional positioning component, and an input and output interface.
  • the processing component is respectively connected to the three-dimensional positioning component, the display component, the memory and the input and output interface for controlling the overall operation of the entire individual transcranial map navigation system, and performing all of the transcranial brain mapping methods provided by the present invention or Part of the steps.
  • the processing component can be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable A gate array (FPGA), controller, microcontroller, microprocessor or other electronic component implementation for performing the above-described transcranial brain mapping method.
  • ASICs application specific integrated circuits
  • DSPs digital signal processors
  • DSPDs digital signal processing devices
  • PLDs programmable logic devices
  • FPGA field programmable A gate array
  • controller microcontroller, microprocessor or other electronic component implementation for performing the above-described transcranial brain mapping method.
  • the display component is coupled to the three-dimensional positioning component for real-time display of the current physical state of the three-dimensional positioning component on the surface of the scalp of the subject and the state in the transcranial map to guide the placement of the transcranial device on the surface of the scalp of the subject.
  • the memory is configured to store various types of data to support operation on an individual trans
  • the memory can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read only memory (EEPROM), and erasable programmable Read only memory (EPROM), programmable read only memory (PROM), read only memory (ROM), magnetic memory, flash memory, and the like.
  • SRAM static random access memory
  • EEPROM electrically erasable programmable read only memory
  • EPROM erasable programmable Read only memory
  • PROM programmable read only memory
  • ROM read only memory
  • magnetic memory flash memory, and the like.
  • flash memory and the like.
  • the three-dimensional positioning component is used to reconstruct the geometric shape of the scalp surface of the subject by using a plurality of discrete points collected from the surface of the scalp of the subject, and realize the scalp surface of the subject at any point in the skull scale coordinate system with millimeter precision. Positioning.
  • the input/output interface is used to realize the connection between the individual transcranial map navigation system and an external transcranial device, such as a transcranial brain treatment device and a transcranial brain imaging device.
  • an external transcranial device such as a transcranial brain treatment device and a transcranial brain imaging device.
  • the individual transcranial map navigation system may also include a conventional power module and a human interface module (such as a keyboard, a mouse, etc.), which are not specifically described herein.
  • the three-dimensional positioning assembly uses a Fastrak magnetic field three-dimensional locator manufactured by Polhemus.
  • the magnetic field three-dimensional locator includes a magnetic field transmitter (Transmitter) and two magnetic field detectors (Sensors).
  • One of the magnetic field detectors is shaped like a Stylus, and the other magnetic field detector is a cube shape.
  • the magnetic field emitter produces a full local magnetic field that defines a hemispherical space with a radius of 305 cm. In this hemisphere space, a frame of reference with the origin of the magnetic field emitter can be generated.
  • the spatial position and attitude of the probe and detector can be quantified.
  • the magnetic field emitter is fixed on the bracket behind the subject, and the detector is fixed on the tibia of the subject with an elastic string, and the probe is held by the experimenter and is tested.
  • the position of the scalp is marked on the surface.
  • the spatial position of the magnetic field detector can be given by the O-XYZ coordinates of the reference frame.
  • the attitude of the magnetic field detector is expressed by the Eular angle.
  • the magnetic field three-dimensional locator also specifies an origin and three positive directions, i.e., defines a detector-specific reference frame O'-X'Y'Z'. It is assumed that the initial detector is located on the positive half-axis of the emitter reference frame X, and the X'Y'Z' axis is the same as the XYZ-axis direction. Then the detector can reach the current pose by three rotations.
  • the detector rotates clockwise azimuth along the Z axis such that X' is in the same direction as the current X' projection on the O-XY plane.
  • the elevation angle (Elevation) ⁇ is rotated forward and backward toward the Z axis such that X' coincides with the current X' direction.
  • the Z' axis and the Y' axis are located at Z" and Y" in Fig. 6.
  • the detector extends the X' axis through the roll angle ⁇ such that Z" and Y" coincide with the current Z' and Y' axes. Therefore, in physical space, the spatial position and attitude of the magnetic field detector can be uniquely described by six dimensions: X, Y, Z, ⁇ , ⁇ , and ⁇ .
  • the magnetic field three-dimensional locator is capable of locating positional information in physical space.
  • the subject's head cannot be kept still, so the collected scalp surface position information is affected by the subject's head movement.
  • the coordinate system determined by the magnetic field emitter is O-XYZ
  • the detector reference system is O'-X'Y'Z'
  • the probe tip position is P
  • we additionally define a reference frame O' -XYZ the origin of this coordinate system is at O' but the direction of the XYZ axis is in the same direction as the magnetic field transmitter coordinate system.
  • the coordinates of the P point in the O-XYZ coordinate system (x 1 , y 1 , z 1 ) are known, and the coordinates of the O' point in the O-XYZ coordinate system are (x 2 , y 2 , z 2 ), attitude parameters.
  • Equation (14) gives a transformation relationship that converts a point in the emitter reference frame to the head reference system by means of detector coordinates and attitude angle. With this transformation relationship, the position at which the probe tip is positioned can be converted to the head reference system that moves with the subject's head.
  • the above-mentioned scalp surface points positioned by the magnetic field three-dimensional locator are still represented in a three-dimensional coordinate system.
  • a fundamental requirement of an individual transcranial map navigation system is to locate points represented in the three-dimensional space in the individual's CPC coordinate system.
  • the present invention uses a sparse sampling-based surface reconstruction algorithm to reconstruct the geometric information of the entire skull using sporadic scatters collected from the skull. Then, using the scale measurement based on the reconstructed scalp surface, the skull points indicated in the head reference frame are positioned into the CPC coordinate system of the individual subject.
  • the specific instructions are as follows:
  • the sampling point consists of two parts, the first part is the four skull landmarks, namely Nz, Iz, AL and AR.
  • the second part is called the reconstruction point and is manually collected by the operator on the surface of the subject's scalp.
  • the four skull landmarks are used together with the reconstruction points in the reconstruction of the skull and define the boundary of the reconstructed skull.
  • the CPC measurement four skull landmarks are used as four measurements of the CPC system.
  • the level point is used for the positioning of the CPC coordinates of the skull points.
  • discrete point clouds P ⁇ x i , y i , z i , i 1, 2, ..., N ⁇ of N points, where N is the landmark point including 4 skulls. All skull sampling points.
  • the origin O of the nose-to-ear coordinate system is defined at the midpoint of the AL-AR connection
  • the direction from O to Nz is the positive direction of the X-axis
  • the direction from the O-point to the AL is the Y-axis.
  • the positive direction, and the positive direction of the Z axis is defined in the cross direction of the XY axis.
  • the result of the sparse point is an unstructured point cloud (a in Figure 9).
  • We introduce the CRUST algorithm see Amenta, N., M. Bern, and M. Kamvysselis, A new Voronoi-based surface reconstruction algorithm, In Proceedings of the 25th annual conference on Computer graphics and interactive techniques. 1998, ACM.p. 415-421.) reconstructed the topological connections between these unstructured point clouds.
  • the result obtained by the CRUST algorithm is a Triangle Patch, TP ⁇ (i,j,k)
  • i,j,k 1,2,...M ⁇ (b in Figure 9), where , i, j, k are the numbers of the points in P, respectively, and each triple (i, j, k) represents three points with topological neighbors. All triangular patches in the TP form a crust of the point cloud P, and the CRUST algorithm ensures that the outer shell has a consistent topography with the real skull surface.
  • the shape of the outer shell of the point set P reconstruction is too "dry" relative to the shape of the scalp surface.
  • the shape of the human scalp surface should be similar to an ellipsoid smooth surface. Therefore, we introduce a spheroidization process to further refine the reconstructed outer casing.
  • N DP is the number of points in the dense point cloud.
  • the N DP is on the order of ⁇ 10K.
  • the dense point cloud DP obtained from the reconstruction of the skull surface is a good approximation of the shape of the real physical scalp surface of the subject.
  • the dense point cloud DP and the four skull level points recorded by the magnetic field three-dimensional locator are in a virtual coordinate space, so we can construct the CPC coordinate system on this DP, and think that the CPC coordinate system is directly
  • the CPC system obtained on the surface of the physical scalp of the subject was approximated.
  • the coordinate transformation operation can also enter the virtual coordinate space in real time.
  • the CPC coordinates of point P are calculated in real time.
  • the operator uses a magnetic field three-dimensional locator to calibrate the four skull level points Nz, Iz, AL and AR on the subject's head, and collect multiple sparse points in the scalp of the subject in a uniform manner. Then, the scalp surface of the subject is reconstructed according to the sampled plurality of sparse points and the CPC coordinates are constructed on the reconstructed scalp surface. Thereafter, the position of the probe on the surface of the subject's scalp will be located in real time in the subject's own CPC coordinates.
  • the position of the probe on the surface of the scalp of the subject will be displayed in real time.
  • the scalp surface of the 3D head model displayed in the individual transcranial map navigation system.
  • the experimenter navigates the marker points on the 3D head model to the region of interest of the experiment by moving the probe according to the visual feedback given by the individual transcranial map navigation system.
  • the probe is physically located on the surface of the subject's scalp. It is the placement position of the transcranial device based on the transcranial brain map, as shown in Figure 10b.
  • the present invention further provides an individual transcranial map navigation system for applying the transcranial brain map to the problem of guiding the individualized placement of the transcranial device.
  • an individual transcranial map navigation system for applying the transcranial brain map to the problem of guiding the individualized placement of the transcranial device.
  • the operator can achieve navigation of the skull target point with millimeter precision.
  • the experimental results show that the navigation method based on transcranial brain map and navigation system can effectively improve the coverage accuracy of the near-infrared measurement of the brain region of interest, and the consistency of measurement positions in different human epithelial layers, thereby improving the near-infrared technology.
  • the detection task induces sensitivity to brain activity.
  • the current mainstream functional near-infrared spectroscopy (fNIRS) device uses a multi-channel measurement method, which usually observes brain activity by a fixed-pitch photopole array. This kind of observation is actually a kind of discrete "multi-point observation", and the different observation points will affect each other, which is mainly due to the shape limitation of the light pole.
  • the transcranial brain map can provide complete cranial-brain correspondence information, which is convenient for the experimenter to plan the position of the photopole.
  • the transcranial brain map navigation method and system thereof provided by the present invention ensure the coverage accuracy of the photopole at the regional level, and even for multi-region coverage (using the same functional near-infrared spectroscopy apparatus for observing multiple brain regions) It also shows a unique advantage.

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Abstract

本发明公开了一种个体经颅脑图谱生成方法，可以将不可见的大脑内的图谱信息投射到可见的头皮表面上，使原本分离的操作空间和效用空间融合在一起。针对将经颅脑图谱应用到指导经颅设备的个体化放置中的问题，本发明进一步提供了一种基于个体特征的经颅脑图谱生成方法及导航系统。实验结果表明，利用本发明可以有效提高近红外测量光极感兴趣脑区的覆盖准确性，以及在不同人上皮层测量位置的一致性，从而提高近红外技术检测任务诱发脑活动的敏感性。

Description

基于个体特征的经颅脑图谱生成方法、导航方法及其系统 技术领域
本发明涉及一种个体经颅脑图谱生成方法，同时涉及一种基于个体特征的经颅脑图谱导航方法，还涉及相应的个体经颅脑图谱导航系统，属于认知神经科学技术领域。
背景技术
当前，认知神经科学所面临的一个重要课题是建立脑功能和脑结构之间的对应关系。以功能磁共振成像(fMRI)、功能近红外光谱(fNIRS)为代表的功能脑成像技术，可以使神经科学的研究者们以非侵入的方式对活体人脑的功能进行观测。
包括经颅脑治疗和经颅脑成像在内的经颅脑映射技术，一直在快速发展，并在脑机制评估和脑损伤治疗方面表现出巨大的潜力。例如，经颅磁刺激(Transcranial Magnetic Stimulation，简称为TMS)通过外部施加的磁场，实现在高时空分辨率下对人脑局部活动的抑制或激发。经颅磁刺激的无创特性使其有助于评估特定脑区域/脑回路和行为之间的因果关系。经颅磁刺激也广泛用于治疗各种神经精神障碍，例如帕金森病、疼痛、成瘾等。值得一提的是，经颅磁刺激作为治疗耐药性抑郁症的临床干预手段，已经获得美国食品药品管理局(FDA)的认证。
经颅脑映射技术通常在可见的头皮表面(称为操作空间)上操作。然而，经颅脑治疗和经颅脑成像的目标区域位于大脑内部(称为效用空间)，从操作者的角度来说，这是从外部不可见的。因此，给定目标位置或效用空间中的某个脑区域标号，在个体头皮表面上定位最佳的成像或刺激位点是非常困难的。这可能导致次优化、不一致的实验结果，甚至冲突的结论。例如，实施经颅磁刺激的线圈在治疗抑郁症的目标区域(例如背侧前额叶皮层)上的放置不一致可能导致治疗结果不同。类似地，fNIRS光极的放置也是至关重要的。不适当的放置可能导致记录皮质位置的偏差，甚至可能覆盖错误的皮质区域。此外，在神经影像研究中的群组分析中，需要将来自不同个体的成像皮质位 置彼此对应以进行不同个体之间结果的比较。目前，将fNIRS光极正确放置在头皮上以覆盖感兴趣的皮层区域并且同时保持成像皮层位置在不同受试个体之间的对应性仍然具有挑战性。其中，可见的操作空间(头皮表面)和不可见的效用空间(大脑内部)之间的分离仍是以有效和准确应用这些经颅脑映射技术的最大挑战之一。
发明内容
本发明所要解决的首要技术问题在于提供一种个体经颅脑图谱生成方法。
本发明所要解决的另一个技术问题在于提供一种基于个体特征的经颅脑图谱导航方法。
本发明所要解决的又一个技术问题在于提供一种个体经颅脑图谱导航系统。
为了实现上述目的，本发明采用下述的技术方案：
根据本发明实施例的第一方面，提供一种基于个体特征的颅面坐标系生成方法，包括如下步骤：
(11)在个体的头皮表面识别五个颅骨标记Nz、Iz、AL、AR和Cz；
(12)将头皮表面和通过Nz、Cz和Iz的平面之间的相交曲线定义为颅骨赤道；
(13)给出头皮表面上的点p，经度曲线可以唯一地确定为头皮表面和通过AL、AR和p的平面之间的相交曲线，p'是颅骨赤道与经度曲线之间的交叉点；
(14)上头皮的任意点p由一对非负实数(p e，p l)唯一确定：
p e＝L NZ-p’/L e，p e∈[01]
p l＝L AL-p/L AL-p-AR，p l∈[01]
其中，L Nz-p'是沿着颅骨赤道的Nz到p'的曲线长度，L e是颅骨赤道的全长；L AL-p是沿着全长为L AL-p-AR的经度曲线从AL到p的曲线长度。
其中较优地，上述颅面坐标系生成方法还包括步骤(15)：在标准半球上建立CPC空间；使用Hammer-Aitoff投影对带有CPC坐标的半球进行平面化，生成在扁平椭圆上呈现的CPC坐标系的地图。
根据本发明实施例的第二方面，提供一种基于个体特征的经颅脑图谱生成方法，包括如下步骤：
(1)按照上述的步骤在个体层面创建颅面坐标系；
(2)建立用于连接颅骨位置与大脑位置的经颅映射系统；
(3)使用马尔可夫链中的两步随机过程构建经颅脑图谱。
其中较优地，所述步骤(2)包括如下子步骤：
使用气球膨胀模型在个体空间中确定对应于给定的头皮表面任意点p的底层皮层位置c；
在所有皮层位置被空间标准化为MNI空间之后，聚合所有(p，c)对，生成确定性的个体经颅脑映射模型。
根据本发明实施例的第三方面，提供一种基于个体特征的经颅脑图谱导航方法，包括如下步骤：
(1)在被试者头皮表面上进行若干个点的稀疏均匀采样，重建出被试者头皮表面的近似曲面；
(2)在所述近似曲面上建立CPC坐标系；
(3)将被试者头皮表面上移动的探笔位置实时转化到上述经颅脑图谱所在的CPC坐标系中，利用经颅脑图谱的信息指导经颅设备在头皮表面的放置。
其中较优地，所述步骤(1)中，采样点包括两个部分，第一部分是4个颅骨标记Nz，Iz，AL和AR，第二部分由操作者手动在被试者头皮表面采集得到。
其中较优地，将基于所述采样点生成的离散点云表示在鼻凹-耳前坐标系统中；其中，鼻凹-耳前坐标系统的原点O定义在AL-AR连线的中点，O点到Nz的方向为X轴正方向，O点到AL的方向为Y轴正方向，而Z轴正方向被定义在XY轴的叉积方向。
其中较优地，采用CRUST算法重建所述离散点云之间的拓补连接，得到三角面片集合TP{(i,j,k)|i,j,k＝1,2,...M}；其中，i，j，k分别是P中点的序号，每个三元组(i，j，k)表示具有拓扑相邻的三个点。
其中较优地，对所述三角面片集合TP{(i,j,k)|i,j,k＝1,2,...M}中的所有三角面片进行非线性插值，得到细分的三角网格；保留所述三角网格 上的顶点，记作致密点云DP＝{x i,y i,z i|i＝1,2,3,...,N DP}，作为所述近似曲面。
根据本发明实施例的第四方面，提供一种个体经颅脑图谱导航系统，包括处理组件、显示组件、存储器、三维定位组件以及输入输出接口；其中，
所述处理组件分别连接三维定位组件、显示组件、存储器和输入输出接口，用于执行上述的经颅脑图谱导航方法中的全部或部分步骤；
所述显示组件与三维定位组件连接，用于实时显示三维定位组件在被试者头皮表面的当前状态及经颅脑图谱中的状态；
所述存储器，用于存储各种类型的数据；
所述三维定位组件，用于利用从被试者头皮表面采集的若干个点，重建出被试者头皮表面的近似曲面；
所述输入输出接口，用于实现所述个体经颅脑图谱导航系统与外部经颅设备的连接。
其中较优地，所述三维定位组件为Fastrak磁场三维定位仪，包括一个磁场发射器和两个磁场探测器；其中一个磁场探测器为探笔形状，另一个磁场探测器是立方体形状。
其中较优地，所述磁场三维定位仪在使用时，所述磁场发射器固定在被试者身后的支架上，立方体形状的磁场探测器被固定在被试者颧骨位置，探笔形状的磁场探测器由实验者持握并在被试者头皮表面上标定位置。
与现有技术相比较，本发明首先提供了一种个体经颅脑图谱生成方法，可以将不可见的大脑内的图谱信息投射到可见的头皮表面上，使原本分离的操作空间和效用空间融合在一起。针对将经颅脑图谱应用到指导经颅设备的个体化放置中的问题，本发明进一步提供了一种个体经颅脑图谱导航系统。实验结果表明，利用本发明可以有效提高近红外测量光极感兴趣脑区的覆盖准确性，以及在不同人上皮层测量位置的一致性，从而提高近红外技术检测任务诱发脑活动的敏感性。
附图说明
图1(a)～图1(e)是经颅脑图谱的系列实施例示意图；
图2是从磁共振图像中识别颅骨标记的示意图；
图3是CPC坐标系的示意图；
图4给出了单个CPC坐标点的概率经颅脑映射示意图；
图5为本发明所提供的个体经颅脑图谱导航系统的结构示例图；
图6为磁场发射器参照系下，磁场探测器的空间位置和姿态表示示意图
图7为物理坐标系到头坐标系的空间变换示意图；
图8为鼻凹-耳前坐标系统的示意图；
图9为头皮表面重建过程的示意图，其中a显示了头皮表面采集的21个无结构散点，b显示了CRUST算法计算得到采样点的拓补关系，c显示了球面化处理得到的重建点云；
图10为本发明所提供的个体经颅脑图谱导航系统的使用状态示意图，其中a为显示组件所显示的屏幕截图，b为实验者进行实际操作的示意图。
具体实施方式
下面结合附图和具体实施例对本发明的技术内容做进一步的详细说明。
前已述及，对经颅成像装置可见的颅骨表面空间和对经颅成像装置不可见的颅内脑空间的分离是有效应用经颅脑映射技术的最大挑战之一。为了解决两个空间的对应问题，本发明首先提出了经颅脑图谱(Transcranial Brain Atlas，简称为TBA)的概念。经颅脑图谱是建立在头皮表面上的脑图谱，它将不可见的大脑内的图谱信息投射到可见的头皮表面(尤其是头皮上表面)上，使研究者或者医生可以直接使用这些涉及脑结构和脑功能的图谱信息。
具体地说，本发明首先显式地构建一个标准的颅骨坐标系统，用来实现对不同个体颅骨表面空间的定量描述。然后，依据颅-脑对应关系在人群上一致性的假设，建立一个标准颅骨表面空间到脑图谱所在的标准脑空间之间的对应关系。最后，本发明从颅骨表面空间-标准脑空间，以及脑图谱提供的标准脑空间-脑分区标号空间这两部分的对应关系中，求解出颅骨表面空间-脑分区标号空间之间的对应关系。作为结果，本发明将对应的脑标准空间和脑图谱中的信息反向呈现到颅骨坐标系统，从而形成一种新型的“经颅脑图谱”。经颅脑图谱的一个重要性质是能够仅仅通过颅骨位置信息，直接推断对应脑分区标号的 信息，因此可以粗略地理解为一个建立在头皮表面上的脑图谱。经颅脑图谱本质上是一个建立在坐标化的头皮表面上的大脑功能地图，即在一个坐标化的大脑空间中，让传统脑图谱对应每个脑部位置及其功能或解剖学标号，从而描绘出经颅脑映射技术可及的各个皮层位置及其对应的图谱标号，并将它们明确呈现在作为可见操作空间的头皮表面上。
经颅脑图谱可以将传统脑图谱中的先验脑分区信息，在人群水平颅-脑对应关系意义下映射到用于经颅脑成像装置放置的颅骨空间中。因此，可以看作是传统脑图谱在经颅脑成像技术领域的扩展。在经颅脑图谱的框架下，经颅数据在脑空间的定位可以转化为对经颅成像装置在颅骨空间的定位，这使得经颅脑映射技术的实时定位成为可能。此外，由于经颅脑图谱的标号信息是在颅骨空间显示的，这个特性非常有利于经颅脑图谱叠加到个体头皮表面进行显示，从而以直观的方式指导经颅成像装置在被试颅骨表面的放置。因此，经颅脑图谱的建立，解决了经颅脑映射技术中操作空间与效用空间分离的矛盾。
图1(a)～图1(e)是经颅脑图谱的系列实施例示意图。如图1(a)所示，假设在头皮表面上定义了统一的颅面坐标系，它描述了可以设置经颅脑映射技术的探头的所有可能的位置，并且将探头设置在给定的颅骨位置(图中黑点所在位置)。对于特定的个体(例如图1(b)中的受试者sub 1)，设置在其头皮表面的探头将能够探及特定皮层位置/脑区域(图中黄点所在位置)。但在群体层面，考虑到个体之间的解剖结构的差异，这种颅-脑对应关系可能不是确定的。如图1(c)所示，在标准化到标准脑空间之后，我们可以捕获这种概率对应关系的空间分布(即黑色圆圈内的彩色区域)。通过给定从大脑图谱所获得的解剖信息，这种概率对应关系能够提供如何从颅骨位置访问每个大脑区域的群体层面的概率，并且将其作为先验知识。经颅脑图谱本质上是为颅面坐标系定义的整个大脑空间映射该先验知识。具体在图1所示的系列实施例中，如果仅针对每个颅骨位置考虑最可能探及的脑分区标号及其关联的概率，则如图1(d)所示的最大似然标号图(MLM)和如图1(e)所示的最大概率图(MPM)可以作为经颅脑映射技术的探头排列的有用指导。
在本发明的实施例中，经颅脑图谱的生成过程主要包括三个步骤：1)在个体层面创建颅面坐标系；2)建立用于连接颅骨位置与大脑位置的经颅映射系统；3)使用马尔可夫链中的两步随机过程构建经颅脑图谱。
下面对经颅脑图谱的详细生成过程进行说明。
1)在个体层面创建颅面坐标系(Cranial surface coordinate system)
颅面坐标系需要满足两个基本要求：第一，它应为个体头皮表面提供一对一的映射；第二，为了便于进行群体层面的研究，对于颅面坐标系中的每个位置，应该使来自不同个体的下层皮层位置在神经解剖学上基本一致。
CPC坐标系的基本思想是在头皮表面上构造一个类似于经纬线的坐标系统。与地理经纬线系统不同的是，CPC坐标系对“经纬度”的确定是利用两次表面比例测量的方式确定的。在本发明的实施例中，通过如下三个步骤在个体的头皮表面建立被称为连续比例坐标空间(简称为CPC空间)的二维比例坐标系：
11)在个体空间(navie space)的头皮表面识别至少五个来源于10-20系统的颅骨标记Nz、Iz、AL、AR和Cz(参见图3(a))。在磁共振图像中识别颅骨标记的示例参见图2，其中，Iz是人类头骨的外枕骨隆起，斜方肌附着于其上；AL和AR是左耳和右耳前点，被识别为耳屏的峰值区域；Nz被确定为鼻梁上部的凹陷位置；Cz被确定为颅表面测地线AL-Cz-AR和Nz-Cz-Iz的交点，并分别平分两条颅表面测地线。
12)将颅骨赤道被定义为头皮表面和通过Nz、Cz和Iz的平面之间的相交曲线(即图3(a)中的曲线1)；
13)给出头皮表面上的点p，经度曲线(即图3(a)中的曲线2)可以唯一地确定为头皮表面和通过AL、AR和p的平面之间的相交曲线，p'是颅骨赤道与经度曲线之间的交叉点。
在以上三步定义的基础上，上头皮(高于由Nz、Iz、AL、AR点指定的曲线)的任意点p都可以由一对非负实数(p e，p l)唯一确定：
p e＝L Nz-p’/L e，p e∈[0 1]              (1)
p l＝L AL-p/L AL-p-AR，p l∈[0 1]           (2)
其中，L Nz-p'是沿着颅骨赤道的Nz到p'的曲线长度，L e是颅骨赤道的全长(从Nz到Iz)；L AL-p是沿着全长为L AL-p-AR的经度曲线从AL到p的曲线长度。如图3(b)所示，作为任意点的p点的表面位置由p'和p分别占这两条曲线的比例唯一地表示，计算公式参见公式(1)和公式(2)。
图3(b)是在头皮表面上建立的二维比例坐标系(简称为CPC坐标系)的示意图。其中，该二维比例坐标系为头皮表面上的任意点p向CPC空间提供一对一的映射。从上面的描述可以看出，CPC坐标系从本质上是在头皮表面上构造一个类似于经纬线的坐标系统。但与地理经纬线不同的是，CPC坐标系对“经纬度”的确定是利用两次表面比例测量的方式确定的。
基于颅骨标记(Nz，Iz，AL，AR和Cz)和CPC坐标系(与尺度和形状成比例)定义的比例关系所确立的对象间对应关系，可以在个体层面的头皮表面上建立合理的解剖学对应关系。为了从单个视角可视化整个头皮表面，如图3(c)所示，在标准半球上建立了一个特殊的CPC空间。然后，使用现有的Hammer-Aitoff投影对带有CPC坐标系的半球进行平面化，生成在扁平椭圆上呈现的CPC坐标系的地图，申请人将其称为BNU地图(Beijing Normal University Map)(参见图3(d))，其实质为标准CPC坐标系的二维投影图像。在BNU地图的基础上，任何与头皮表面相关的脑功能数据都可以在该地图中呈现，从而能够在不同项目、人群、实验室甚至不同成像模式之间实现有效的比较。
2)建立用于连接颅骨位置与大脑位置的经颅脑映射模型(Transcranial brain mapping，简称为TBM)
一旦在个体层面的头皮表面建立了CPC空间，使用成熟的气球膨胀模型(Okamoto&Dan，2005)，可以在个体空间(例如，个体3D MRI图像)中确定对应于给定的头皮表面任意点p的底层皮层位置c。在所有皮层位置被空间归一化为标准脑空间(即MNI空间)之后，聚合所有(p，c)对，可以生成确定性的个体经颅脑映射模型。然后，通过集成所有的个体经颅脑映射模型来生成群体层面上的概率经颅脑映 射模型：
P(c|p)            (3)
p(p e，p l)∈CPC，c(x，y，z)∈C，C是标准脑空间的子集，并包含经颅脑映射技术相关的所有皮层位置。当从给定坐标的头皮表面上任意点p(p e，p l)开始刺激或记录时，概率经颅脑映射模型给出每个靶向皮层位置c(x，y，z)的概率。
图4给出了单个CPC坐标所对应的概率经颅脑映射模型。当给出一对CPC坐标，例如P＝(0.4，0.6)，在每个个体层面的头皮表面上可以确定对应的点B，其所对应的皮层投射点C的位置使用成熟的气球膨胀模型在个体层面上的磁共振图像空间中识别出来。在图4中，下半部分的表格显示了任意点P＝(0.4，0.6)对应在概率经颅映射模型的不同位置的相应概率。
从颅骨空间一点到标号空间一个标号的映射，可以看做是一个两步映射。首先，从颅骨空间S映射到脑空间B，再从脑空间B映射到标号空间L。由于两步映射都是概率映射，因此，这个过程也可以看做一个两步随机过程。由于脑空间和脑分区标号的对应关系是由人脑自身的结构规律决定的，我们假定对于脑坐标空间中任意一点，其对应到各个脑区标号的概率是确定的，而与之前颅骨坐标空间到脑坐标空间的对应路径无关。因此，这个两步随机过程存在马尔可夫(Markov)性质。
3)使用马尔可夫链中的两步随机过程构建经颅脑图谱(Transcranial brain atlas)
本领域技术人员知晓，脑图谱是在概率框架中构建的。例如，传统的脑图谱(例如MNI图谱)描述的基本关系是条件概率：
P(l|b)             (4)
其中，b(x，y，z)∈B，B是标准脑空间的子集，并且包含图谱的脑模板中的所有可能的脑组织点；l∈L，L包含所有可能的图谱标号，每个图谱标号都表示脑图谱中的特定脑区。对于给定的一对l和b，P(l|b)表示人脑中的位置b处出现图谱标号l可能性。
相应地，经颅脑图谱描述的基本关系也是条件概率：
P(l|p)              (5)
其中p(p e，p l)∈CPC和l∈L。
在本发明的实施例中，可以通过马尔可夫链中的两步随机过程构建经颅脑图谱。具体地说，第一步：作为输入的给定点p(p e，p l)通过概率经颅映射P(c|p)被映射到标准脑空间中的皮层位置c(x，y，z)。第二步：特定的c(x，y，z)被映射到标号空间L中的标号l。研究者或者医生可以单独地通过皮层位置c(x，y，z)来预测图谱标号l，而无需考虑头皮表面上的位置p(p e，p l)，这里提供了公式(6)：
P(l|c，p)＝P(l|c)             (6)
因此，两步随机过程使用了本领域技术人员常用的马尔科夫链。其中，假设皮层(域c)上的点是脑中(域b)的点的子集，P(l|p)可以使用公式(3)中的P(c|p)和公式(4)中的P(l|b)来计算。具体而言，如果p和c离散化，那么Chapman-Kolmogorov方程式表示：
Figure PCTCN2018084000-appb-000001
其中，p i是CPC空间中的离散位置(即任意点，下同)，i＝1，2，...，Np；c j是C在标准脑空间中的离散位置，j＝1，2，...，Nc；l k是特定脑图谱的图谱标号，k＝1，2，...，N 1。
需要说明的是，上述步骤所构建的经颅脑图谱是一种概率图谱，即当探头在给定坐标的头皮表面的任意位置p刺激或记录时，通过经颅脑图谱可以给出由l标记的每个靶向脑区域被探及的概率。它将不可见的脑内的图谱标号信息投射到可见的头皮上来，使得研究者或者医生可以直接使用这些脑结构和功能图谱信息，大大提升了脑图谱在经颅脑映射技术中的作用。
综上所述，本发明首先提供了一个基于两步马尔可夫链模型的概率框架作为经颅脑图谱的理论基础。其中，第一步是从CPC空间中的头皮位置到MNI空间中的下划线皮层位置的颅骨-皮层映射(crainio-cortical mapping)。第二步是使用传统的大脑图谱构建经颅脑图谱，实质是一个从MNI空间的皮层位置到图谱标号空间的映射。需要说明的是，本发明利用概率框架提供了一个可扩展的经颅脑图谱模型，上述第二步所使用的大脑图谱可以由任何其他脑图谱替代。虽然，在本发明中仅提供了三种基于宏观解剖学的脑图谱(BA图谱，AAL 图谱和LPBA图谱)用于构建经颅脑图谱，但类似的功能图谱、连接图谱以及其他图谱都可以被用来为特定应用提供功能性的经颅脑图谱。
在现有技术中，经颅脑成像技术所面临的一个首要问题，就是如何将头盖骨测量所得到的功能信息定位到脑图谱中，即经颅定位问题。另外，与传统脑成像技术不同的是，这类技术在实际操作中，还需要事先规划经颅设备(包括经颅脑成像装置或经颅脑治疗装置)在头盖骨上的放置位置。因此，经颅脑成像技术定位问题的另一方面，是如何利用脑图谱中的解剖信息指导经颅设备的个体化放置，即经颅导航问题。
针对上述两个问题，本发明的整体解决思路是这样的：首先在经颅设备可见的颅骨空间构建一个标准化的坐标系，用来定量刻画整个经颅技术所能覆盖的整个头盖骨空间。然后基于大样本结构像数据，求解头盖骨空间到标准脑空间以及头盖骨空间到脑图谱标号空间的在人群水平的对应关系。以此方式解决经颅定位和经颅导航两方面的问题。下面对此展开详细具体的说明。
在经颅脑图谱的框架下，经颅数据在脑空间的定位可以转化为对经颅设备在颅骨空间的定位，这使得经颅脑映射技术的实时定位成为可能。此外，由于经颅脑图谱的标号信息是在颅骨空间显示的，这个特性非常利于将经颅脑图谱叠加到个体头皮表面进行显示，从而以直观的方式指导经颅设备在被试者头皮表面的放置。
为了将经颅脑图谱应用到解决经颅脑成像技术的实际定位和导航问题中，本发明提供了一种基于稀疏采样点的表面重建技术，并在其基础上实现了面向颅骨坐标系的自动定位算法。该自动定位算法能够仅通过在被试者头皮表面上的数十个点的稀疏均匀采样，重建出被试者头皮表面的近似曲面，并在此曲面上实现被试者个体CPC坐标系的重建。在上述自动定位算法的基础上，本发明提出了一种基于颅骨坐标系和经颅脑图谱的个体经颅脑图谱导航系统。该系统可以借助磁场三维定位仪的实时定位功能，将被试者头皮表面移动的探笔位置实时转化到经颅脑图谱所在的CPC坐标系中，以此实现计算空间的经颅脑图谱与物理空间的被试者头皮表面的融合，从而利用经颅脑图谱的信息指导经颅设备在头皮表面的放置。
如图5所示，本发明所提供的个体经颅脑图谱导航系统至少包括处理组件、显示组件、存储器、三维定位组件以及输入输出接口。其中，处理组件分别连接三维定位组件、显示组件、存储器和输入输出接口，用于控制整个个体经颅脑图谱导航系统的整体操作，执行本发明所提供的经颅脑图谱导航方法中的全部或部分步骤。在示例性实施例中，处理组件可以被一个或多个应用专用集成电路(ASIC)、数字信号处理器(DSP)、数字信号处理设备(DSPD)、可编程逻辑器件(PLD)、现场可编程门阵列(FPGA)、控制器、微控制器、微处理器或其他电子元件实现，用于执行上述经颅脑图谱导航方法。显示组件与三维定位组件连接，用于实时显示三维定位组件在被试者头皮表面的当前物理状态及经颅脑图谱中的状态，以便指导经颅设备调整在被试者头皮表面的放置位置。存储器被配置为存储各种类型的数据以支持在个体经颅脑图谱导航系统上的操作。这些数据的示例包括用于在个体经颅脑图谱导航系统上操作的任何应用程序或方法的指令等。存储器可以由任何类型的易失性或非易失性存储设备或者它们的组合实现，如静态随机存取存储器(SRAM)，电可擦除可编程只读存储器(EEPROM)，可擦除可编程只读存储器(EPROM)，可编程只读存储器(PROM)，只读存储器(ROM)，磁存储器，快闪存储器等。三维定位组件用于利用从被试者头皮表面采集的若干个离散点，重建出被试者头皮表面的几何形状，并以毫米级精度实现将被试者头皮表面任意一点在颅骨比例坐标系统的定位。输入输出接口用于实现本个体经颅脑图谱导航系统与外部经颅设备，例如经颅脑治疗设备和经颅脑成像设备等的连接。除了上述功能模块之外，本个体经颅脑图谱导航系统还可以包括常规的电源模块及人机接口模块(例如键盘、鼠标等)，在此就不具体说明了。
在本发明的一个实施例中，为了获取物理空间中的空间定位，三维定位组件采用Polhemus公司生产的Fastrak磁场三维定位仪。这种磁场三维定位仪包括一个磁场发射器(Transmitter)和两个磁场探测器(Sensor)。其中一个磁场探测器被制作成探笔(Stylus)的形状，另一个磁场探测器是立方体形状，为描述方便，我们分别称之为探笔和探测器。在磁场三维定位仪工作时，磁场发射器会产生一个充满局部磁场，这个磁场定义了一个半径为305cm的半球空间。在这个半球 空间中，能够生成一个以磁场发射器为原点的参照系。在这个参照系中，探笔和探测器的空间位置和姿态都可以被定量表示。上述磁场三维定位仪在使用时，磁场发射器被固定在被试者身后的支架上，探测器被用弹性细绳固定在被试者颧骨位置，探笔由实验者持握并在被试者头皮表面上标定位置。
对于上述参照系中的一个磁场探测器，首先磁场探测器的空间位置可以由参照系的O-XYZ坐标给出。然后，用欧拉角(Eular angle)表述磁场探测器的姿态。另外，磁场三维定位仪也指定了一个原点和三个正方向，即定义了一个探测器特异的参照系O’-X’Y’Z’。假定最初探测器位于发射器参照系X正半轴上，且X’Y’Z’轴与XYZ轴方向相同。则探测器可以通过三次旋转到达当前姿态。第一，在O-XY平面上，探测器沿Z轴顺时针转过方位角(Azimuth)Ψ使得X’与当前X’在O-XY平面上的投影同向。第二，在O-X’Z平面上，向Z轴正反向转过仰角(Elevation)θ，使得X’与当前X’方向重合。此时，Z’轴和Y‘轴位于图6中的Z”和Y”处。最后，在O’-Y”Z”面上，探测器延X’轴转过滚动角(Roll)φ，使得Z”和Y”与当前的Z’和Y’轴重合。因此在物理空间中，磁场探测器的空间位置和姿态，可以由X、Y、Z、Ψ、θ、φ六个维度唯一描述。
尽管磁场三维定位仪能够定位出物理空间中的位置信息。然而，在实际操作中，被试者的头部无法保持静止，因此采集到的头皮表面位置信息会受到被试者头动的影响。理想情况下，我们希望头皮表面位置的描述是建立在一个与被试者头部相对静止的参照系中。为了解决这个问题，我们将立方体形状的探测器与被试者头皮表面固定，形成一个相对头皮表面静止的参照系统，并且融合探笔和探测器的位置和姿态信息。
如图7所示，假定磁场发射器确定的坐标系为O-XYZ，探测器参照系为O’-X’Y’Z’，探笔笔尖位置为P；此外我们额外定义一个参照系O’-XYZ，该坐标系原点位于O’处但XYZ轴方向与磁场发射器坐标系同向。已知P点在O-XYZ坐标系下的坐标(x 1,y 1,z 1)，O’点在O-XYZ 坐标系下的坐标为(x 2,y 2,z 2)，姿态参数为(ψ,θ,φ)，我们需要求解P点在O’-X’Y’Z’的坐标(x 3,y 3,z 3)。
首先，根据OP，OO’和O’P的向量关系，我们可以得到
Figure PCTCN2018084000-appb-000002
即
Figure PCTCN2018084000-appb-000003
由于
Figure PCTCN2018084000-appb-000004
由
Figure PCTCN2018084000-appb-000005
经过三次旋转变换得到，存在变换关系：
Figure PCTCN2018084000-appb-000006
使得
Figure PCTCN2018084000-appb-000007
即
Figure PCTCN2018084000-appb-000008
带入式(9)，得
Figure PCTCN2018084000-appb-000009
于是有
(x 3,y 3,z 3)＝(x 1-x 2,y 1-y 2,z 1-z 2)·A -1         (14)
式(14)给出了借助探测器坐标和姿态角将发射器参照系中的一点转换到头参照系的变换关系。借助这个变换关系，探笔笔尖定位到的位置，都可转换到随被试者头移动的头参照系。
上述经过磁场三维定位仪定位的头皮表面点，仍然表示在一个三维坐标系中。然而，个体经颅脑图谱导航系统的一个根本需求是将表示在三维立体空间中的点，在被试者个体的CPC坐标系中定位出来。为此，本发明采用基于稀疏采样的表面重建算法，利用从颅骨上采集到的零星散点，重建出整个颅骨的几何信息。然后，利用基于重建头皮表面的比例测量，将表示在头参照系中的颅骨点定位到被试者个体的CPC坐标系中。具体说明如下：
首先，我们对颅骨表面进行了采样。采样点包括两个部分，第一部分是4个颅骨地标点，即Nz，Iz，AL和AR。第二部分被称为重建点，由操作者手动在被试者头皮表面采集得到。这里，4个颅骨地标点一方面和重建点一起被用在颅骨重建中，并定义了重建颅骨的边界；另一方面，在CPC测量中，4个颅骨地标点作为CPC系统构建的4个测量水准点，用于颅骨点的CPC坐标定位。在颅骨表面采样后，我们得到N个点的离散点云P{x i,y i,z i,i＝1,2,...,N}，其中N是包括4个颅骨地标点在内的所有颅骨采样点。为了方便表面重建算法的实施，我们对离散点云进行了一个预处理，将其表示在鼻凹-耳前坐标系统中。如图8所示，其中，鼻凹-耳前坐标系统的原点O定义在AL-AR连线的中点，O点到Nz的方向为X轴正方向，O点到AL的方向为Y轴正方向，而Z轴正方向被定义在XY轴的叉积方向。
稀疏采点得到的结果是一个无结构的点云(图9中的a)，我们引入CRUST算法(参见Amenta，N.，M.Bern，and M.Kamvysselis，A new Voronoi-based surface reconstruction algorithm，in Proceedings of the 25th annual conference on Computer graphics and interactive techniques.1998，ACM.p.415-421.)重建出这些无结构点云之间的拓补连接。CRUST算法得到的结果是一个三角面片 集合(Triangle Patch)，TP{(i,j,k)|i,j,k＝1,2,...M}(图9中的b)，其中，i，j，k分别是P中点的序号，每个三元组(i，j，k)表示具有拓扑相邻的三个点。TP中的所有三角面片形成了点云P的一个外壳(crust)，CRUST算法可以保证这个外壳的与真实颅骨表面具有一致的拓补结构。
在稀疏采样下，点集P重建的外壳形状上相对头皮表面形状会过于“干瘪”。考虑到人类头皮表面形状应该是近似于椭球光滑曲面。因此我们引入一个球面化的过程对重建得到的外壳进行进一步完善。在球面化的过程中，我们对每一个三角面片进行多次迭代的非线性插值。经过对集合TP中的所有三角面片进行非线性插值，我们可以得到一个细分的三角网格。我们保留了三角网格上的顶点，记作致密点云DP＝{x i,y i,z i|i＝1,2,3,...,N DP}(图9中的c)，其中N DP是致密点云中的点数。对于推荐的～10量级的采样，N DP的量级大约是～10K。
颅骨表面重建得到的致密点云DP是被试者真实物理头皮表面形状的良好近似。并且，此时的致密点云DP和磁场三维定位仪记录到的4个颅骨水准点同处于一个虚拟的坐标空间，因此我们可以在这个DP上构建CPC坐标系统，并认为这个CPC坐标系统与直接在被试者物理头皮表面上得到的CPC系统近似。这样，对于磁场三维定位仪的探笔新纪录被试者物理头皮表面上的任意一点P，则经过上述坐标变换操作，也能实时进入到这个虚拟坐标空间，根据前述的CPC定位算法，我们可以实时计算出P点的CPC坐标。
在导航操作开始时，操作者使用磁场三维定位仪标定被试者头上的4个颅骨水准点Nz，Iz，AL和AR，并以均匀的方式在被试者头皮采集多个稀疏点。然后，按照采样到的多个稀疏点重建被试者头皮表面并在重建头皮表面上构建CPC坐标。此后，探笔在被试者头皮表面的位置，会实时定位被试者自己的CPC坐标中。
由于被试者头皮表面的CPC坐标和个体经颅脑图谱导航系统中预置的3D头模型的CPC坐标是一一对应的，因此，探笔在被试者头皮表面的位置，将实时显示在个体经颅脑图谱导航系统中显示的3D头模型的头皮表面。这样，随着磁场三维定位仪的探笔在被试者头皮表面上 的移动，3D头模型上的标记点也会相应移动。实验者按照个体经颅脑图谱导航系统给出的视觉反馈，通过移动探笔将3D头模型上的标记点导航到实验的感兴趣区域，此时的探笔在被试者头皮表面上物理位置就是基于经颅脑图谱的经颅设备的放置位置，如图10b所示。
综上所述，针对将经颅脑图谱应用到指导经颅设备的个体化放置中的问题，本发明进一步提供了一种个体经颅脑图谱导航系统。在一项对10-20地标点的标定实验中，我们验证了在个体经颅脑图谱导航系统指导下的真实实验中，操作者可以实现毫米级精度下对颅骨目标点的导航。最后，我们对基于经颅脑图谱的个体经颅脑图谱导航系统在真实经颅脑成像实验中的可行性进行了验证。实验结果表明，基于经颅脑图谱的导航方法及导航系统，可以有效提高近红外测量光极感兴趣脑区的覆盖准确性，以及在不同人上皮层测量位置的一致性，从而提高近红外技术检测任务诱发脑活动的敏感性。
另一方面，目前主流的功能近红外光谱(fNIRS)设备采用多通道测量方式，通常由一个固定间距的光极阵列实现对脑活动的观测。这种观测实际上是一种离散的“多点观测”，不同观测点之间会相互影响，这主要是由于光极的形状限制。经颅脑图谱能够提供完整的颅-脑对应信息，便于实验者对光极放置位置进行全局规划。在一项真实的fNIRS实验中，我们将基于经颅脑图谱的个体经颅脑图谱导航系统应用到多通道fNIRS的光极放置中。实验结果表明，相比传统10-20方法，经颅脑图谱指导下的光极放置能够有效提高多通道fNIRS测量通道对感兴趣脑区的覆盖准确性，以及测量通道在不同被试者上的观测位置的一致性，从而提高fNIRS探测任务诱发脑活动的敏感性。因此，本发明所提供的经颅脑图谱导航方法及其系统对于保证光极在区域水平的覆盖准确性，甚至对于多区域覆盖(用同一台功能近红外光谱设备对多个脑区进行观测)也能体现出独特的优势。
以上对本发明所提供的基于个体特征的经颅脑图谱生成方法、导航方法及其系统进行了详细的说明。对本领域的一般技术人员而言，在不背离本发明实质精神的前提下对它所做的任何显而易见的改动，都将构成对本发明专利权的侵犯，将承担相应的法律责任。

Claims (12)

  1. 一种基于个体特征的颅面坐标系生成方法，其特征在于包括如下步骤：
    (11)在个体的头皮表面识别五个颅骨标记Nz、Iz、AL、AR和Cz；
    (12)将头皮表面和通过Nz、Cz和Iz的平面之间的相交曲线定义为颅骨赤道；
    (13)给出头皮表面上的点p，经度曲线可以唯一地确定为头皮表面和通过AL、AR和p的平面之间的相交曲线，p'是颅骨赤道与经度曲线之间的交叉点；
    (14)上头皮的任意点p由一对非负实数(p e，p l)唯一确定：
    p e＝L NZ-p’/L e，p e∈[01]
    p l＝L AL-p/L AL-p-AR，p l∈[01]
    其中，L Nz-p'是沿着颅骨赤道的Nz到p'的曲线长度，L e是颅骨赤道的全长；L AL-p是沿着全长为L AL-p-AR的经度曲线从AL到p的曲线长度。
  2. 如权利要求1所述的颅面坐标系生成方法，其特征在于还包括步骤(15)：在标准半球上建立CPC空间；使用Hammer-Aitoff投影对带有CPC坐标的半球进行平面化，生成在扁平椭圆上呈现的CPC坐标系的地图。
  3. 一种基于个体特征的经颅脑图谱生成方法，其特征在于包括如下步骤：
    (1)按照权利要求1所述的步骤在个体层面创建颅面坐标系；
    (2)建立用于连接颅骨位置与大脑位置的经颅映射系统；
    (3)使用马尔可夫链中的两步随机过程构建经颅脑图谱。
  4. 如权利要求3所述的经颅脑图谱生成方法，其特征在于所述步骤(2)包括如下子步骤：
    使用气球膨胀模型在个体空间中确定对应于给定的头皮表面任意点p的底层皮层位置c；
    在所有皮层位置被空间标准化为MNI空间之后，聚合所有(p，c) 对，生成确定性的个体经颅脑映射模型。
  5. 一种基于个体特征的经颅脑图谱导航方法，其特征在于包括如下步骤：
    (1)在被试者头皮表面上进行若干个点的稀疏均匀采样，重建出被试者头皮表面的近似曲面；
    (2)在所述近似曲面上建立CPC坐标系；
    (3)将被试者头皮表面上移动的探笔位置实时转化到权利要求3所述经颅脑图谱所在的CPC坐标系中，利用经颅脑图谱的信息指导经颅设备在头皮表面的放置。
  6. 如权利要求5所述的经颅脑图谱导航方法，其特征在于：
    所述步骤(1)中，采样点包括两个部分，第一部分是4个颅骨标记Nz，Iz，AL和AR，第二部分由操作者手动在被试者头皮表面采集得到。
  7. 如权利要求6所述的经颅脑图谱导航方法，其特征在于：
    将基于所述采样点生成的离散点云表示在鼻凹-耳前坐标系统中；其中，鼻凹-耳前坐标系统的原点O定义在AL-AR连线的中点，O点到Nz的方向为X轴正方向，O点到AL的方向为Y轴正方向，而Z轴正方向被定义在XY轴的叉积方向。
  8. 如权利要求7所述的经颅脑图谱导航方法，其特征在于：
    采用CRUST算法重建所述离散点云之间的拓补连接，得到三角面片集合TP{(i,j,k)|i,j,k＝1,2,...M}；其中，i，j，k分别是P中点的序号，每个三元组(i，j，k)表示具有拓扑相邻的三个点。
  9. 如权利要求8所述的经颅脑图谱导航方法，其特征在于：
    对所述三角面片集合TP{(i,j,k)|i,j,k＝1,2,...M}中的所有三角面片进行非线性插值，得到细分的三角网格；保留所述三角网格上的顶点，记作致密点云DP＝{x i,y i,z i|i＝1,2,3,...,N DP}，作为所述近似曲面。
  10. 一种个体经颅脑图谱导航系统，其特征在于包括处理组件、显示组件、存储器、三维定位组件以及输入输出接口；其中，
    所述处理组件分别连接三维定位组件、显示组件、存储器和输入输出接口，用于执行权利要求5所述的经颅脑图谱导航方法中的全部 或部分步骤；
    所述显示组件与三维定位组件连接，用于实时显示三维定位组件在被试者头皮表面的当前状态及经颅脑图谱中的状态；
    所述存储器，用于存储各种类型的数据；
    所述三维定位组件，用于利用从被试者头皮表面采集的若干个点，重建出被试者头皮表面的近似曲面；
    所述输入输出接口，用于实现所述个体经颅脑图谱导航系统与外部经颅设备的连接。
  11. 如权利要求10所述的个体经颅脑图谱导航系统，其特征在于：
    所述三维定位组件为Fastrak磁场三维定位仪，包括一个磁场发射器和两个磁场探测器；其中一个磁场探测器为探笔形状，另一个磁场探测器是立方体形状。
  12. 如权利要求11所述的个体经颅脑图谱导航系统，其特征在于：
    所述磁场三维定位仪在使用时，所述磁场发射器固定在被试者身后的支架上，立方体形状的磁场探测器被固定在被试者颧骨位置，探笔形状的磁场探测器由实验者持握并在被试者头皮表面上标定位置。
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