Intracranial pressure detection method and system based on multi-wavelength photoacoustic imaging

Abstract

The invention discloses an intracranial pressure detection method and system based on multi-wavelength photoacoustic imaging. The method comprises the following steps: respectively irradiating the neurocranium of a subject by using a plurality of lasers with different wavelengths; for single irradiation, original photoacoustic data generated by the neurocranium of the subject is collected, image reconstruction is carried out, a two-dimensional amplitude image under the irradiation is obtained, and a corresponding blood vessel mask is generated according to the image; performing spectral unmixing on the blood vessel mask, and then extracting the response under the irradiation; combining the response under each illumination to generate a multi-wavelength response vector; performing least square fitting on the multi-wavelength response vector by using a molar extinction coefficient matrix to calculate the relative concentration of oxyhemoglobin and the relative concentration of deoxyhemoglobin; and calculating the intracranial pressure of the subject according to the relative concentration of the oxyhemoglobin and the relative concentration of the deoxyhemoglobin. According to the invention, non-invasive, quantitative and real-time monitoring of deep cerebral vessels can be realized, and the intracranial pressure of a subject can be accurately evaluated.

Description

Technical Field

[0001] This invention belongs to the field of biomedical photoacoustic imaging and monitoring technology, and more specifically, relates to a method and system for intracranial pressure detection based on multi-wavelength photoacoustic imaging. Background Technology

[0002] The clinical demand for non-invasive, real-time monitoring of brain function continues to grow. Existing methods such as magnetic resonance angiography (MRA), magnetic resonance imaging (MRI), computed tomography angiography (CTA), and transcranial Doppler (TCD) have limitations in terms of penetration depth, temporal resolution, or functional information. For example, the temporal resolution of MRI is insufficient for rapid dynamic monitoring; transcranial ultrasound is significantly affected by skull attenuation and scattering, limiting its stability and quantitative capabilities.

[0003] Photoacoustic imaging, combining the advantages of optical absorption's sensitivity to hemoglobin and ultrasound propagation's friendliness to deep tissues, possesses the capability for functional imaging related to blood oxygenation. However, a mature protocol for achieving stable imaging and quantification of blood oxygenation parameters in deep brain vessels (such as the middle cerebral artery, MCA) without craniotomy, and establishing a reliable quantitative correlation with intracranial pressure (ICP), still lacks a mature method. Therefore, a non-invasive assessment protocol suitable for intact skull conditions is urgently needed. Summary of the Invention

[0004] The main objective of this invention is to provide a method and system for intracranial pressure detection based on multi-wavelength photoacoustic imaging, so as to overcome the shortcomings of the prior art.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] The first aspect of this invention provides a method for detecting intracranial pressure based on multi-wavelength photoacoustic imaging. The method is not for diagnostic or therapeutic purposes and includes: irradiating the subject's brain with multiple lasers of different wavelengths; for each single irradiation: acquiring raw photoacoustic data generated by the subject's brain and reconstructing the image to obtain a two-dimensional amplitude image under that irradiation; extracting vascular skeleton pixels from the two-dimensional amplitude image to generate a corresponding vascular mask; extracting the response under that irradiation after spectral unmixing of the vascular mask; combining the responses from each irradiation to generate a multi-wavelength response vector; performing least-squares fitting on the multi-wavelength response vector using a molar extinction coefficient matrix containing the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at the multiple different wavelengths to calculate the relative concentrations of oxyhemoglobin and deoxyhemoglobin; and calculating the subject's intracranial pressure based on the relative concentrations of oxyhemoglobin and deoxyhemoglobin.

[0007] Preferably, before performing the image reconstruction, the method further includes: performing energy normalization processing on several frames of acquired raw photoacoustic data; the image reconstruction specifically includes: performing image reconstruction on several frames of raw photoacoustic data after energy normalization processing to obtain multi-frame two-dimensional amplitude images under this illumination.

[0008] Preferably, before extracting the vascular skeleton pixels, the method further includes: binarizing the two-dimensional amplitude image, identifying connected regions in the binarized image, and removing connected regions with an area smaller than a set threshold to eliminate noise points in the two-dimensional amplitude image; extracting the vascular skeleton pixels specifically includes: extracting the vascular skeleton pixels in the two-dimensional amplitude image after noise point removal.

[0009] Preferably, extracting the vascular skeleton pixels specifically includes: performing morphological thinning on the binary image of the two-dimensional amplitude image to obtain the vascular skeleton; calculating the local vascular radius in the vascular skeleton; removing connected components in the vascular skeleton whose local vascular radius is not within a preset range to obtain the final vascular skeleton pixels, so as to generate the corresponding vascular mask.

[0010] Preferably, before performing spectral demixing on the vascular mask, the method further includes: mapping the pixels in the vascular mask to the actual physical depth based on the placement angle of the probe relative to the temporal bone of the subject and the propagation speed of the sound signal, thereby constructing a depth-compensated vascular mask image; mapping the depth-compensated vascular mask image to an equidistant coordinate system to obtain a vascular mask correction image; and specifically, performing spectral demixing on the vascular mask includes: performing spectral demixing on the vascular mask correction image.

[0011] Preferably, the relative concentrations of oxyhemoglobin and deoxyhemoglobin are as follows:

[0012] ;

[0013] in, Includes the relative concentrations of oxyhemoglobin and deoxyhemoglobin; This refers to the multi-wavelength response vector; This is a molar extinction coefficient matrix, with each column corresponding to the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at different wavelengths; The L2 norm of a vector.

[0014] Preferably, the intracranial pressure of the subject is:

[0015] ;

[0016] ;

[0017] in, The intracranial pressure of the subject; Oxygen saturation; This refers to the relative concentration of oxyhemoglobin. This refers to the relative concentration of deoxyhemoglobin. These are the first fitted parameters; is the second fitting parameter.

[0018] A second aspect of the present invention provides an intracranial pressure detection system based on multi-wavelength photoacoustic imaging, the system comprising: a laser, a data acquisition unit, a probe, an optical fiber, and a processor; the laser is connected to the optical fiber and is used to emit laser light to irradiate the brain of a subject; the data acquisition unit is connected to the probe and is used to acquire raw photoacoustic data generated by the brain of the subject; the processor is connected to the data acquisition unit, and the system is used to implement the intracranial pressure detection method based on multi-wavelength photoacoustic imaging.

[0019] A third aspect of the present invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described above.

[0020] A fourth aspect of the present invention provides a non-transitory computer-readable storage medium storing computer instructions for causing a computer to execute the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described above.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) A method for detecting intracranial pressure based on multi-wavelength photoacoustic imaging is provided. The photoacoustic data of the subject is obtained based on the photoacoustic imaging principle. The photoacoustic data is reconstructed to obtain the vascular mask in the image. The response vector obtained after spectral unmixing of the vascular mask is fitted by least squares using a molar extinction coefficient matrix containing the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at multiple different wavelengths to obtain the relative concentrations of oxyhemoglobin and deoxyhemoglobin, so as to calculate the intracranial pressure of the subject. Compared with traditional ultrasound, MRI and other methods, this method directly obtains blood spectral information through photoacoustic multi-wavelength imaging, which has better sensitivity and specificity. Moreover, this method is based entirely on the photoacoustic imaging system and the standard temporal window acoustic coupling method. It does not require skull fenestration or invasive detection, avoiding the risk of infection and complications of the subject. It can be implemented quickly and meets the needs of dynamic and continuous monitoring of intracranial pressure.

[0023] (2) Before image reconstruction, the energy normalization of several frames of original photoacoustic data was performed frame by frame to effectively eliminate the signal deviation caused by laser energy fluctuations and ensure the consistency of multi-wavelength data. Combined with depth mapping compensation, the depth error introduced by the difference between the incident geometry of the temporal window and the sound velocity was corrected, making the blood vessel positioning and signal amplitude more uniform among different subjects.

[0024] (3) This method significantly reduced the statistical variance of blood oxygen factor and improved the stability and generalization ability of the regression model under cross-subject and time point conditions. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of an intracranial pressure detection method based on multi-wavelength photoacoustic imaging provided in an embodiment of the present invention.

[0027] Figure 2 This is a flowchart of a preferred embodiment of the intracranial pressure detection method based on multi-wavelength photoacoustic imaging provided by the present invention.

[0028] Figure 3 This is a schematic diagram of a test scenario provided in an embodiment of the present invention.

[0029] Figure 4 This is an example diagram of deep cerebral blood vessel segmentation provided in an embodiment of the present invention.

[0030] Figure 5 This is a schematic diagram of the geometric measurement results of deep cerebral blood vessels under MRI.

[0031] Figure 6 This is a schematic diagram of PA-MRI registration.

[0032] Figure 7 This is a regression diagram of arterial blood oxygen saturation-intracranial pressure provided in an embodiment of the present invention.

[0033] Figure 8 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0034] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0036] Furthermore, in the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "horizontal," "vertical," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] In the description of this specification, the references to terms such as "an embodiment," "a particular embodiment," or "the embodiment" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] Figure 1 This is a flowchart of the intracranial pressure detection method based on multi-wavelength photoacoustic imaging provided in an embodiment of the present invention. Please refer to... Figure 1 The method of the present invention includes operations S100-S400.

[0039] Operate S100 to irradiate the subject's brain with multiple lasers of different wavelengths; for each single irradiation: collect the raw photoacoustic data generated by the subject's brain and perform image reconstruction to obtain a two-dimensional amplitude image under that irradiation; extract the vascular skeleton pixels in the two-dimensional amplitude image to generate the corresponding vascular mask; after spectral demixing of the vascular mask, extract the response under that irradiation.

[0040] In a preferred embodiment, before image reconstruction, the method further includes: performing energy normalization processing on several frames of acquired raw photoacoustic data. Image reconstruction specifically includes: performing image reconstruction on several frames of raw photoacoustic data after energy normalization processing to obtain multi-frame two-dimensional amplitude images under that illumination.

[0041] In a preferred embodiment, before extracting the vascular skeleton pixels, the method further includes: binarizing the two-dimensional amplitude image, identifying connected regions in the binarized image, and removing connected regions with an area smaller than a set threshold to eliminate noise points in the two-dimensional amplitude image. Extracting the vascular skeleton pixels specifically includes: extracting the vascular skeleton pixels from the two-dimensional amplitude image after noise point removal.

[0042] In a preferred embodiment, extracting vascular skeleton pixels specifically includes: performing morphological thinning on the binary image of the two-dimensional amplitude image to obtain the vascular skeleton; calculating the local vascular radius in the vascular skeleton; removing connected components whose local vascular radius is not within a preset range to obtain the final vascular skeleton pixels, thereby generating a corresponding vascular mask.

[0043] In a preferred embodiment, before spectral demixing the vascular mask, the method further includes: mapping the pixels in the vascular mask to the actual physical depth based on the placement angle of the probe collecting the raw photoacoustic data generated by the subject's skull relative to the subject's temporal bone and the propagation speed of the acoustic signal, to construct a depth-compensated vascular mask image; and mapping the depth-compensated vascular mask image to an equidistant coordinate system to obtain a vascular mask correction image. Spectral demixing of the vascular mask specifically includes: performing spectral demixing on the vascular mask correction image.

[0044] This embodiment improves spatial localization by performing time-lapse / geometric remapping based on the condition of the intact skull. Least-squares unmixing is performed within the vascular mask, and residual quality control is output to improve unmixing robustness.

[0045] Operate S200 to combine the responses under each irradiation to generate a multi-wavelength response vector.

[0046] Operate S300 and use the molar extinction coefficient matrix, which contains the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at multiple different wavelengths, to perform least squares fitting on the multi-wavelength response vector to calculate the relative concentrations of oxyhemoglobin and deoxyhemoglobin.

[0047] In a preferred embodiment, the relative concentrations of oxyhemoglobin and deoxyhemoglobin are as follows:

[0048] ;

[0049] in, Includes the relative concentrations of oxyhemoglobin and deoxyhemoglobin; It is a multi-wavelength response vector; This is a molar extinction coefficient matrix, with each column corresponding to the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at different wavelengths; The L2 norm of a vector.

[0050] Operate S400 to calculate the subject's intracranial pressure based on the relative concentrations of oxyhemoglobin and deoxyhemoglobin.

[0051] In a preferred embodiment, the intracranial pressure of the subject is:

[0052] ;

[0053] ;

[0054] in, The intracranial pressure of the subject; Oxygen saturation; This refers to the relative concentration of oxyhemoglobin. This refers to the relative concentration of deoxyhemoglobin. These are the first fitted parameters; This is the second fitting parameter. In this embodiment, non-invasive functional parameters are established using statistical modeling. The relationship with intracranial pressure was studied to achieve trend assessment and quantitative inference.

[0055] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0056] by Figure 2 Taking the preferred embodiment shown as an example, combined with Figures 3-7 The following provides a further illustrative description of the intracranial pressure detection method based on multi-wavelength photoacoustic imaging provided by the present invention.

[0057] Building such Figure 3 The test scenario shown includes a tunable pulsed laser (i.e., the laser itself), an ultrasound receiving array (i.e., optical fiber and probe), a data acquisition card, a computing and processing unit (implemented via a computer and signal generator), and a display and storage module (implemented via a computer). The laser sends a synchronization signal to the data acquisition card; the output of the ultrasound receiving array is pre-amplified and then connected to the data acquisition card; the computing and processing unit completes image reconstruction, region of interest extraction, spectral unmixing and statistical modeling, and outputs arterial blood oxygen saturation (…). (Image and intracranial pressure (ICP) estimation results. See also...) Figure 2 The intracranial pressure detection method based on multi-wavelength photoacoustic imaging includes the following steps 1-8.

[0058] Step 1, Subject preparation and positioning. The probe and optical path are positioned through the temporal window to ensure good acoustic coupling.

[0059] Step 2, Multi-wavelength data acquisition. Select K wavelengths. For each wavelength, N frames of raw photoacoustic data and corresponding laser energy are acquired. K>1, N>1, the wavelength range is 700nm~900nm, the array center frequency is 7.5MHz, and the sampling rate is 40MSa / s.

[0060] Step 3, Energy Normalization. Reconstruct the amplitude of the k-th wavelength in the i-th frame. According to energy Normalization is performed: .

[0061] Step 4, Image Reconstruction. After energy normalization, the original photoacoustic radio frequency signals at each wavelength are reconstructed. For example, a Delay-Sum (DAS) algorithm, or a time-reversal algorithm, minimum variance beamforming algorithm, or other reconstruction methods can be used. Specifically, the geometric parameters of the ultrasonic transducer (e.g., number of probe elements, element spacing, center frequency, bandwidth) and the sound velocity model are input to obtain the images at each wavelength. Two-dimensional amplitude image below The image unit is relative photoacoustic intensity, and it is stored after Hilbert envelope detection to enhance dynamic range and display effect.

[0062] Step 5, background suppression and region of interest extraction. In the reconstructed image... Based on this, the target blood vessel region is extracted. Specifically, the image is binarized using a global or adaptive thresholding method (e.g., Otsu's method or quantile-based thresholding); all connected regions are identified, and regions with areas smaller than a set threshold are removed. The goal is to eliminate noise points, with the connected component area threshold set based on pixel calibration; morphological refinement is performed on the binary image to obtain the vascular skeleton; local vascular radii are calculated based on distance transform, and connected components with radii exceeding a reasonable range are removed to form the final vascular mask. ,like Figure 4 As shown, it is used for subsequent spectral unmixing and blood oxygen estimation.

[0063] Step 6, Depth Mapping Compensation. Depth correction is performed considering the geometric distortion and sound velocity differences of the incident sound waves through the temporal window. Specifically, the placement angle of the probe relative to the temporal bone is known. Speed ​​of sound propagation Establish a two-dimensional sector scan or plane wave propagation model; analyze image pixels. Perform mapping using geometric functions Correct it to the actual physical depth. ,in, Pre-calculation can be performed using trigonometric functions or numerical simulation; linear or spline interpolation methods can be used to remap the corrected image to an equidistant coordinate system; resulting in more accurate photoacoustic images with better spatial positioning, such as... Figure 6 As shown, this provides accurate depth information for subsequent blood oxygen calculations. Figure 5 This is a schematic diagram comparing the results of this invention with the NMR results. Figure 6 The goal is to register the two results to obtain a photoacoustic image with more accurate spatial positioning.

[0064] Step 7: Multi-wavelength spectral demixing and SO2 estimation. Within the blood vessel mask, multi-wavelength photoacoustic signals are used for spectral demixing. Specifically, photoacoustic amplitudes at K wavelengths are collected for each pixel or local region of interest to form a response vector. Construct a molar extinction coefficient matrix containing oxyhemoglobin HbO2 and deoxyhemoglobin Hb. The matrix contains the extinction coefficient for each wavelength, and is solved using the constrained least squares method. The relative concentrations of oxyhemoglobin HbO2 and deoxyhemoglobin Hb were estimated. and Calculate oxygen saturation based on the unmixing results. Preferably, in order to reduce the impact of light intensity fluctuations and noise, pixel neighborhood weighted averaging or regularization methods (such as Tikhonov regularization, non-negative constraint NNLS) can be used to improve robustness.

[0065] Step 8, Intracranial Pressure Calculation. Linear regression modeling is used on a sample with clinically calibrated intracranial pressure. The regression relationship between arterial oxygen saturation and intracranial pressure was fitted and predicted as follows: Figure 7 As shown.

[0066] The intracranial pressure detection method based on multi-wavelength photoacoustic imaging provided in this invention has the following advantages. (1) On sample data with clinical intracranial pressure calibration, the blood oxygen factor obtained by this method shows a significant negative correlation with the intracranial pressure level, indicating that this index can be used as an effective non-invasive alternative parameter for intracranial pressure changes. Compared with traditional ultrasound, MRI and other methods, this invention directly obtains blood spectral information through photoacoustic multi-wavelength imaging, which has better sensitivity and specificity. (2) By frame-by-frame energy normalization, the signal deviation caused by laser energy fluctuations is effectively eliminated, ensuring the consistency of multi-wavelength data. Combined with depth mapping compensation, the depth error introduced by the difference between the incident geometry of the temporal window and the sound velocity is corrected, making the vascular positioning and signal amplitude more uniform among different subjects. (3) The above measures significantly reduce the statistical variance of the blood oxygen factor and improve the stability and generalization ability of the regression model under cross-subject and time point conditions. (4) The scheme of this invention is entirely based on the photoacoustic imaging system and the standard temporal window acoustic coupling method, without the need for cranial fenestration or invasive detection, avoiding the risk of infection and complications for the subjects. The entire testing process is standardized, can be implemented quickly, meets the needs for dynamic and continuous monitoring of intracranial pressure, and is safer.

[0067] Based on the same inventive concept, and corresponding to any of the methods described in the above embodiments, this application also provides an intracranial pressure detection system based on multi-wavelength photoacoustic imaging. The system includes: a laser, a data acquisition unit, a probe, an optical fiber, and a processor.

[0068] A laser is connected to an optical fiber to emit laser light to irradiate the subject's brain. A data acquisition unit is connected to a probe to collect raw photoacoustic data generated by the subject's brain. A processor is connected to the data acquisition unit, and the system is used to implement the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any of the above embodiments.

[0069] Specifically, the laser emits lasers of different wavelengths to irradiate the subject's brain; during each irradiation, the data acquisition unit collects several frames of raw photoacoustic data generated by the subject's brain; the processor executes other operations in the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any of the above embodiments.

[0070] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any of the above embodiments.

[0071] Figure 8This embodiment illustrates a more specific hardware structure of an electronic device, which may include a processor 810, a memory 820, an input / output interface 830, a communication interface 840, and a bus 850. The processor 810, memory 820, input / output interface 830, and communication interface 840 are interconnected internally via the bus 850.

[0072] The processor 810 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0073] The memory 820 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 820 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 820 and is called and executed by the processor 810.

[0074] The input / output interface 830 is used to connect input / output modules to enable information input and output. Input / output modules can be configured as components within the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touchscreens, microphones, various sensors, etc., while output devices may include displays, speakers, vibrators, indicator lights, etc.

[0075] The communication interface 840 is used to connect the communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0076] Bus 850 includes a pathway for transmitting information between various components of the device, such as processor 810, memory 820, input / output interface 830, and communication interface 840.

[0077] It should be noted that although the above-described device only shows the processor 810, memory 820, input / output interface 830, communication interface 840, and bus 850, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0078] The electronic devices described above are used to implement the corresponding intracranial pressure detection method based on multi-wavelength photoacoustic imaging in any of the foregoing embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0079] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides a non-transitory computer-readable storage medium that stores computer instructions for causing a computer to execute the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any of the above embodiments.

[0080] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0081] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to execute the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0082] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0083] Additionally, to simplify the description and discussion, and to avoid obscuring the embodiments of this application, the well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Furthermore, the apparatus may be shown in block diagram form to avoid obscuring the embodiments of this application, and this also takes into account the fact that the details of the implementation of these block diagram apparatuses are highly dependent on the platform on which the embodiments of this application will be implemented (i.e., these details should be fully understood by those skilled in the art). While specific details (e.g., circuits) have been set forth to describe exemplary embodiments of this application, it will be apparent to those skilled in the art that the embodiments of this application can be implemented without these specific details or with variations thereof. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0084] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0085] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for detecting intracranial pressure based on multi-wavelength photoacoustic imaging, wherein the method is for non-diagnostic purposes, characterized in that... The method includes: The subject's brain was irradiated with lasers of multiple different wavelengths. For each single irradiation: the raw photoacoustic data generated by the subject's brain was collected and the image was reconstructed to obtain a two-dimensional amplitude image under that irradiation; the vascular skeleton pixels in the two-dimensional amplitude image were extracted to generate a corresponding vascular mask; the response under that irradiation was extracted after spectral demixing of the vascular mask. Combine the responses under each irradiation to generate a multi-wavelength response vector; Using a molar extinction coefficient matrix containing the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at multiple different wavelengths, the multi-wavelength response vector is fitted with least squares to calculate the relative concentrations of oxyhemoglobin and deoxyhemoglobin. Intracranial pressure was calculated based on the relative concentrations of oxyhemoglobin and deoxyhemoglobin.

2. The intracranial pressure detection method based on multi-wavelength photoacoustic imaging according to claim 1, characterized in that, Before performing the image reconstruction, the method further includes: performing energy normalization processing on several frames of acquired raw photoacoustic data; The image reconstruction specifically includes: performing image reconstruction on several frames of original photoacoustic data after energy normalization processing to obtain multi-frame two-dimensional amplitude images under this illumination.

3. The intracranial pressure detection method based on multi-wavelength photoacoustic imaging according to claim 1, characterized in that, Before extracting the vascular skeleton pixels, the method further includes: binarizing the two-dimensional amplitude image, identifying connected regions in the binarized image, and removing connected regions with an area smaller than a set threshold to eliminate noise points in the two-dimensional amplitude image; Extracting the vascular skeleton pixels specifically includes: extracting the vascular skeleton pixels from the two-dimensional amplitude image after noise removal.

4. The intracranial pressure detection method based on multi-wavelength photoacoustic imaging according to claim 1 or 3, characterized in that, Extracting the vascular skeleton pixels specifically includes: Morphological refinement is performed on the binary image of the two-dimensional amplitude image to obtain the vascular skeleton; Calculate the local vessel radius in the vascular skeleton, and remove connected components whose local vessel radius is not within a preset range to obtain the final vascular skeleton pixels, so as to generate the corresponding vascular mask.

5. The intracranial pressure detection method based on multi-wavelength photoacoustic imaging according to claim 1, characterized in that, Before performing spectral demixing on the vascular mask, the method further includes: Based on the placement angle of the probe relative to the temporal bone of the subject and the propagation speed of the sound signal, the pixels in the vascular mask are mapped to the actual physical depth to construct a depth-compensated vascular mask image. The depth-compensated vascular mask image is mapped onto an equally spaced coordinate system to obtain the vascular mask corrected image; The spectral demixing of the blood vessel mask specifically includes: performing spectral demixing on the corrected image of the blood vessel mask.

6. The intracranial pressure detection method based on multi-wavelength photoacoustic imaging according to claim 1, characterized in that, The relative concentrations of oxyhemoglobin and deoxyhemoglobin are: ； in, Includes the relative concentrations of oxyhemoglobin and deoxyhemoglobin; This refers to the multi-wavelength response vector; This is a molar extinction coefficient matrix, with each column corresponding to the extinction coefficients of oxyhemoglobin and deoxyhemoglobin at different wavelengths; The L2 norm of a vector.

7. The intracranial pressure detection method based on multi-wavelength photoacoustic imaging according to claim 1 or 6, characterized in that, The intracranial pressure of the subject was: ； ； in, The intracranial pressure of the subject; Oxygen saturation; This refers to the relative concentration of oxyhemoglobin. This refers to the relative concentration of deoxyhemoglobin. These are the first fitted parameters; is the second fitting parameter.

8. An intracranial pressure detection system based on multi-wavelength photoacoustic imaging, characterized in that, The system includes: a laser, a data acquisition unit, a probe, an optical fiber, and a processor; The laser is connected to the optical fiber and is used to emit laser light to irradiate the subject's brain. The data acquisition device is connected to the probe and is used to collect raw photoacoustic data generated by the subject's brain. The processor is connected to the data acquisition unit, and the system is used to implement the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any one of claims 1-7.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any one of claims 1-7.

10. A non-transitory computer-readable storage medium storing computer instructions, characterized in that, The computer instructions are used to cause the computer to execute the intracranial pressure detection method based on multi-wavelength photoacoustic imaging as described in any one of claims 1-7.

Images