The present invention relates to the field of neuro-intensive care unit technology. In particular, it involves an in vivo non-invasive intracranial pressure monitoring device and method based on meningeal absorbance changes.
Increased ICP is common in brain diseases such as craniocerebral trauma, intracranial infection, cerebrovascular disease, and brain tumor. It can compress brain tissue and even cause brain herniation, causing adverse consequences. Accurate monitoring of intracranial pressure changes, reasonable confirmation of intracranial pressure intervention cut-offs, and effective control of intracranial pressure have become the key to reducing the mortality rate and improving the prognosis of neurological function.
Invasive ICP monitoring is regarded as the gold standard for intracranial pressure monitoring due to its high accuracy and continuous monitoring. The main monitoring methods include ventricular, parenchymal, subdural, epidural, etc. However, the clinical application of invasive intracranial pressure monitoring is limited to a considerable extent due to procedure-related complications such as intracranial hemorrhage and infection, as well as factors such as high cost and zero-point drift. Therefore, the search for an accurate, reliable, inexpensive, and continuously monitored non-invasive ICP monitoring technology has become the current clinical work. In particular, the neuro intensive care unit (ICU) is an urgent problem to be addressed.
International scholars are conducting relevant research on non-invasive intracranial pressure monitoring, such as intraocular pressure measurement by tonometry, optic nerve sheath diameter (ONSD) measurement by ocular ultrasound, transcranial Doppler ultrasound (TCD), somatosensory evoked potentials (SEP), and flash visual evoked potentials (flash). visual evoked potential (FVEP) and electroencephalogram (EEG) techniques to analyze ICP. However, there are shortcomings such as large measurement error and unsustainability, and further research is needed.
The object of the present invention is to provide an in vivo non-invasive intracranial pressure monitoring device and method based on meningeal absorbance changes, which can monitor intracranial ICP under non-invasive conditions. Easy-to-use, accurate, reliable, infection-free, and continuous dynamic monitoring greatly reduces the pain of patients in ICP monitoring. It can also provide an objective basis for doctors to diagnose diseases, judge conditions, and formulate further diagnosis and treatment plans.
In order to achieve the above purpose, the invention provides an in vivo noninvasive intracranial pressure monitoring and method based on meningeal absorbance changes. The monitoring device includes a signal excitation module, a spectral data acquisition module, and a data processing module. The signal excitation module includes a laser and an optical parametric oscillator. The spectral data acquisition module includes a spectrometer and its supporting data acquisition software. Several mirrors are arranged between the output of the laser and the input of the optical parametric oscillator to adjust the optical path. The output end of the optical parametric oscillator is successively set up with a coaxial lens group and a fiber bundle, and the optical fiber beam outlet is connected to the monitoring object. The probe of the spectrometer is in contact with the monitoring object, and the probe is in the same plane as the optical fiber beam outlet.
An in vivo non-invasive intracranial pressure monitoring method based on changes in meningeal absorbance, including the following steps:
Preferably, the pretreatment and fixation in the step S1 comprise: anesthesia, removing and disinfecting the hair in the middle part of the skull of the monitoring subject, the monitoring subject lying supine, the body position is straight, and the head is at the level of the body axis.
Preferably, the irradiation site is the midpoint of the anterior fontanelle.
Preferably, the detection site in the step S3 is: any point within the radius of 0˜3 cm with the irradiation site as the center of the circle. Preferably, the near-infrared pulsed laser of a certain wavelength is one of 700 nm, 725 nm, 750 nm, 775 nm, and 800 nm. Preferably, the near-infrared pulsed laser of a certain wavelength is 700 nm and 800 nm.
Preferably, the data processing and absorbance calculations in the step S5 comprise:
Near-infrared light has very good penetration for biological tissues and body fluids. The relative energy change between reflected and incident light is related to the absorbance and reflectance at the incident interface. The brain consists of the skull, dura mater, arachnoid, perichondrium and brain parenchyma. The thickness of the meninges changes slightly due to changes in intracranial pressure. At the same time, the thickness of the meninges affects the absorption and attenuation of light. Therefore, when NIR light is transmitted through the skull, the light signals emitted from the surface of the tissue will carry information about the structure and thickness of the meninges. By analyzing the information carried by these light signals, the monitoring of intracranial pressure can be realized.
Accordingly, an in-vivo non-invasive intracranial pressure monitoring device and method of the present invention using the above-described structure based on changes in meningeal absorbance has the following technical effects:
The technical solution of the present invention is described in further detail below by means of the accompanying drawings and embodiments.
In order to more clearly describe the technical solutions in the embodiments or prior art of the present invention. The accompanying drawings to be used in the description of the embodiments or prior art will be briefly described below. Obviously, the accompanying drawings in the following description are merely exemplary. To a person of ordinary skill in the art, other embodiments of the drawings may be obtained by extending the drawings according to the provided drawings without creative labor.
The technical scheme of this invention is further described hereinafter by means of the accompanying drawings and embodiments.
Unless otherwise defined, technical or scientific terms used in this invention shall have the ordinary meaning understood by persons having ordinary skill in the field to which the invention belongs.
Intracranial pressure monitoring was performed in rats in vivo using an in vivo noninvasive intracranial pressure monitoring device based on changes in meningeal absorbance of the present invention and an invasive intracranial pressure monitoring device in the prior art. Rats were selected as male SD rats, weighing 510 g. Source: Beijing Viton Lihua Laboratory Animal Technology Co., Ltd.
As shown in
The signal excitation module is mainly based on a lamp-pumped pulsed Nd:YAG laser (Q-Smart 450) and an optical parametric oscillator (BB-OPO) for optical signal excitation.
The Nd:YAG laser acts as a pump source and is capable of emitting a fixed wavelength laser at 1064 nm. With the addition of a double frequency module, a fixed wavelength laser of 532 nm can be emitted. The laser energy can be controlled by special control software or touch screen.
A 532 nm laser (pump light) is passed into an optical parametric oscillator. The optical parametric oscillator also has a special control computer, control protocol and control software. By adjusting the set value in the control software, it is possible to generate laser light in the range of 680-990 nm (signal light) and 1200-2400 nm. This embodiment uses only 700 nm, 725 nm, 750 nm, 775 nm, 800 nm specific wavelength near-infrared pulsed lasers.
As shown in
The spectral data acquisition module uses the ASC-UVNIR2 compact spectrometer to detect the original optical signal, and the JC spectrum software is used to display and save the data.
The intracranial pressure data acquisition module uses the GE Dash 4000 monitor, medical pressure sensor, and ICM+ multimodal monitoring software to monitor and record intracranial pressure data in real time. Medical pressure sensors are used to measure intracranial pressure, and monitors and ICM+ are used to monitor and record intracranial pressure data in real time.
In vivo non-invasive intracranial pressure monitoring in rats is performed using the above devices. The process is shown in
Drill holes with a skull drill at the marked location. Be careful not to injure the meninges only through the skull. The needle of the medical sensor is inserted into the left lateral ventricle to a depth of 4.5 mm.
Detection of light signal intensity includes:
ICM+ software and Python language are used to complete the processing of raw data. The following steps include data format conversion and data segmentation:
Using ICM+ software, the raw ICP monitoring data is converted into a common “.csv” format.
This system defines the moment when intracranial pressure is about to change (before the cisterna manga is injected into the mouse) as time of 0. At the same time, the ICP data recorded before time 0 is removed. According to the injection dose label, the ICP monitoring values were divided into different data segments to compare the differences in intracranial pressure response under different injection doses.
The ICP data at different stages were averaged. The result was taken as the ICP value at the current injection dose. The curve of ICP values at different injection doses was plotted as shown in
The results showed that injection of saline from the cisterna manga induced an increase in intracranial pressure in rats. This is because when saline is injected, it directly affects the flow and volume of cerebrospinal fluid. The increased volume of fluid in the cranium in turn increases the pressure on the ventricular system, which is manifested as an increase in intracranial pressure. At the same time, there is a compensatory mechanism in the cranium that reduces the increase in intracranial pressure through a variety of means, such as cerebrospinal fluid circulation, cerebral blood flow, etc., so that there is a decreasing phase in the ICP monitoring curve. However, the compensatory capacity of the cranial brain is limited, and with the increase of the injected dose, it will still lead to the elevation of ICP.
Based on the wavelength-background spectral intensity data obtained for 7 min, the following measures were taken to reduce the experimental errors: i. In order to prevent the instability of the electronic components when the spectrometer was turned on, which led to the instability of the obtained data, the data of the first 2 min should be rounded off; ii. The resolution of the spectrometer used was 0.21 nm, and the three columns of spectral values at a specific wavelength and at a specific wavelength±0.21 nm were selected. From the three columns of spectral data at each wavelength of 700 nm, 725 nm, 750 nm, 775 nm, 800 nm, respectively, find the minimum value, and average the three minimum values to get the noise value at that wavelength.
The incident laser intensity at each wavelength detected is subtracted from the noise value at that wavelength separately. The average value is taken as the incident laser energy at that wavelength. The transmitted laser intensity at each detected wavelength is subtracted from the noise value at that wavelength, and the average value is taken as the transmitted laser energy at that wavelength. The average value is taken as the transmitted laser energy at that wavelength.
Absorbance was calculated using the formula:
A is the absorbance,
The results are shown in
By analyzing the data of brain absorbance and intracranial pressure at 700 nm, 725 nm, 750 nm, 775 nm and 800 nm wavelength lasers. The results showed better correlation at 700 nm and 800 nm wavelengths. Afterwards, the relationship between absorbance A and ICP at 700 nm and 800 nm wavelengths was plotted by data fitting, and the relationship equation was also derived. The results are shown in
The ICP values obtained from the 2 fitted equations were then analyzed separately for consistency with the ICP values obtained through invasive lateral ventricular monitoring in Example 1. The results are shown in
Therefore, the present invention adopts one of the above-described in-vivo non-invasive intracranial pressure monitoring devices and methods based on changes in meningeal absorbance. Compared with the traditional invasive intracranial pressure monitoring technique, the non-invasive monitoring method is capable of monitoring the patient's ICP in a non-invasive manner, which has the advantages of safety, low risk of infection, and continuous dynamic monitoring. It can greatly reduce the pain of patients in the process of monitoring ICP. It also has the advantages of low cost, high sensitivity, fast response time and no electromagnetic interference.
Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention is described in detail with reference to the preferred embodiments. The person of ordinary skill in the field should understand that the technical solution of the present invention can still be modified or equivalent replacement. And these modifications or equivalent substitutions cannot make the modified technical solution depart from the spirit and scope of the technical solution of the present invention.
Number | Date | Country | Kind |
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2023117597964 | Dec 2023 | CN | national |