Vascular morphological parameter in-situ detection device and method based on heat transfer theory principle

Abstract

The invention relates to a blood vessel morphological parameter in-situ detection device and method based on a heat transfer theory principle, and the device comprises a core detection module (1) which comprises a thermal excitation source (11), a temperature sensor array (12) and a flexible substrate (13), and the temperature sensor array is arranged on the flexible substrate; the miniaturized electronic system (2) is connected with the core detection unit and used for controlling power output of the thermal excitation source (11) and receiving signals of the temperature sensor array (12); and the flexible packaging structure (5) wraps the core detection module (1) and the miniaturized electronic system (2). The blood vessel morphological parameter non-invasive sensing device serves as an independent component to be integrated on a multi-modal biosensor, a blood vessel morphological parameter non-invasive sensing system is established, the modeling uncertainty of a multi-physical field conduction model of hemodynamic indexes across tissue layers is reduced, and the early monitoring and control capability on vascular diseases is improved. Compared with the prior art, the system has the advantages of high integration, high accuracy, high stability and the like.

Description

Technical Field

[0001] This invention relates to the field of wearable biosensors, and in particular to a device and method for in-situ detection of vascular morphological parameters based on the principle of heat transfer. Background Technology

[0002] The circulatory system is a core physiological network for maintaining homeostasis, and its hemodynamic characteristics directly affect tissue perfusion efficiency and organ function. Vascular diseases caused by the accumulation of blood waste have become the leading cause of death worldwide, and their pathological progression often exhibits insidious characteristics. Conventional biochemical indicators are insufficient to effectively reflect early hemodynamic abnormalities. While various specialized detection technologies and devices have emerged for key hemodynamic parameters such as blood flow and blood pressure, including digital subtraction angiography, Doppler ultrasound, and laser speckle imaging, these traditional methods are generally based on large, specialized medical equipment and require the assistance of medical personnel. They are ill-suited for high-frequency or continuous hemodynamic monitoring, thus hindering timely and convenient health management. Non-invasive wearable hemodynamic monitoring devices can operate in non-clinical environments such as at home or during exercise, offering continuous and real-time monitoring. They can capture subtle or incidental physiological changes, providing timely warnings of potential vascular lesions and helping to eliminate the time delay from disease onset to detection. Therefore, they have gradually attracted widespread research interest.

[0003] Current research indicates that non-invasive wearable hemodynamic monitoring technology is developing in a multimodal manner, mainly including blood flow sensing systems based on thermal conduction effects or Doppler ultrasound principles, wearable blood pressure sensors, photoplethysmography (PPG) blood oxygen monitoring modules, and vascular mechanical vibration detection devices, among other novel wearable sensing devices. However, from a technical implementation perspective, most wearable sensors lack in-situ vascular morphology parameter acquisition mechanisms, resulting in systematic errors when constructing multi-physics field transmission models across tissue layers (tissue-vessel-blood). This unobservability of vascular morphological features (depth, diameter, and spatial configuration) directly leads to a lack of modeling dimensions for the mapping relationship between sensing signals and physiological parameters, ultimately limiting the theoretical accuracy boundary of the measurement system. Therefore, the core technological bottleneck currently facing the field of wearable hemodynamic monitoring lies in the lack of a complete non-invasive sensing system for vascular morphology parameters.

[0004] Patent CN117752312A discloses a device for non-invasive continuous hemodynamic parameter monitoring, including a sensor module, a control module, and an actuation module. The sensor module comprises a flexible ionization sensor array with N measurement channels, and the acquired electrical signals reflect the lateral distribution of the measured arterial pressure on the skin surface. The control module receives the electrical signals acquired by each measurement channel in real time and obtains the pressure output signal of the sensor module based on these signals. The actuation module is dynamically adjusted based on the pressure output signal to adaptively maintain the pressure applied to the measured artery at a desired pressure level, thereby continuously tracking average blood pressure and obtaining continuous arterial pressure pulse wave signals. However, since the device itself lacks the ability to measure vascular morphology parameters and locate blood vessels, the design contains a large number of redundant measurement channels and requires pre-calibration formulas for additional calibration of the measurement results.

[0005] Among existing technologies, only ultrasound imaging sensors possess the capability to visualize vascular morphology, potentially eliminating the interference of individual anatomical differences on signal interpretation by acquiring vascular geometric parameters in real time. However, both fully integrated wearable solutions and modular quasi-wearable solutions face core challenges such as high manufacturing complexity and large computational resource requirements, resulting in significant economic obstacles to their clinical application. Furthermore, while vascular diameter detection technology based on light energy accumulation and photoacoustic tomography integrating hemodynamic parameters show some potential, their reliance on high-energy pulsed lasers severely restricts miniaturization. Especially under the engineering constraints of flexible packaging, low-power operation, and biocompatibility required for wearable monitoring, existing optical sensing paradigms struggle to overcome the dual technical barriers of optimizing light transmission paths and improving photoelectric conversion efficiency.

[0006] Patent CN114939201A discloses a wearable non-invasive arteriovenous fistula (AVF) blood flow monitoring device. This device, designed based on the principle of fluid heat transfer, is a wireless wearable electronic device for non-invasively measuring AVF blood flow in patients undergoing maintenance hemodialysis due to renal failure. It includes a top-layer PDMS package, a back-end processing module, a middle PDMS partition package, a front-end testing module, and a bottom PDMS package. However, establishing a quantitative relationship between blood flow and temperature change at a single point relies on a simplified physical model, making it susceptible to various interference factors. Therefore, it cannot escape the dependence on large-scale medical imaging equipment in the background; otherwise, the variable vascular morphology would lead to significant measurement errors.

[0007] Therefore, how to achieve in-situ acquisition of vascular parameters while ensuring the wearability of the device, and then complete the model dimension compensation of the mapping relationship between sensor signals and physiological parameters, is a major challenge that urgently needs to be overcome in the field of hemodynamic monitoring. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art by providing an in-situ detection device and method for vascular morphology parameters based on the principle of heat transfer. This device has the characteristics of high integration, high accuracy, and high stability, and can realize non-invasive detection of vascular parameters in non-clinical environments, thereby improving the accuracy and reliability of hemodynamic monitoring.

[0009] The objective of this invention can be achieved through the following technical solution: an in-situ detection device for vascular morphological parameters based on the principle of heat transfer, comprising: The core detection module includes a thermal excitation source, a temperature sensor array, and a flexible substrate, wherein the temperature sensor array is disposed on the flexible substrate; A miniaturized electronic system, connected to the core detection module, is used to control the power output of the thermal excitation source and receive signals from the temperature sensor array; A flexible packaging structure encapsulates the core detection module and miniaturized electronic system, forming a biocompatible interface.

[0010] Furthermore, the thermal excitation source is a coiled resistance wire heater, the surface of which is covered with a flexible heat insulation layer; The temperature sensor array consists of multiple negative temperature coefficient thermistors arranged in a linear array to form multiple high-precision temperature measurement points; The flexible substrate is a flexible printed circuit board, on which a temperature sensor array and a miniaturized electronic system are integrated.

[0011] Furthermore, the miniaturized electronic system includes a BLE-WiFi dual-mode SoC, a 16-bit Σ-Δ ADC, and a power module, wherein the power module includes a charge pump for voltage conversion and an electronic switch for controlling heating power.

[0012] Furthermore, the flexible encapsulation structure is a silicone elastomer.

[0013] Furthermore, it also includes a power supply component that powers the core detection module and the miniaturized electronic system.

[0014] Furthermore, it also includes medical ultra-thin double-sided tape, which is used to mechanically connect the device to the skin to be tested.

[0015] The present invention also provides a method for in-situ detection of vascular morphological parameters using the aforementioned device, comprising the following steps: Thermal excitation is applied to the surface of the skin to be tested using a thermal excitation source; A temperature sensor array is used to collect temperature response signals at different locations on the skin surface in real time. Based on the temperature field evolution information, predict the steady state of the temperature field and calculate the thermal relaxation time constant τ at each measuring point; Based on the distribution law of thermal relaxation time constant τ, a multidimensional response relationship between vascular morphological parameters and thermal relaxation time is established. Vascular morphology parameters are obtained through inversion calculation using a neural network model.

[0016] Furthermore, the thermal relaxation time constant τ is calculated as follows: the temperature rise curve is normalized based on the steady-state temperature rise value at each measuring point, and the time taken for the normalized temperature rise curve to rise to 0.85 is the thermal relaxation time constant. The vascular morphology parameters include vascular depth and vascular diameter.

[0017] Furthermore, in establishing the multidimensional response relationship between vascular morphology parameters and thermal relaxation time, compensation is made for the misaligned mounting state of the sensor and vascular structure based on the principle of virtual heat source. Specifically, thermal excitation is achieved by precisely controlling the power of the thermal excitation source through a miniaturized electronic system. The temperature signal is converted into an analog quantity by a temperature sensor array, and the analog quantity is transmitted to the miniaturized electronic system. The miniaturized electronic system completes the conversion of the temperature response signal and wireless transmission to the user terminal.

[0018] Furthermore, obtaining vascular morphology parameters through inversion calculation of neural network models means that the user terminal uses LabVIEW to program information transmitted from a miniaturized electronic system to achieve analysis of temperature signals and parsing of vascular parameters.

[0019] Compared with the prior art, the present invention has the following beneficial effects: Overcoming core technological bottlenecks: While ensuring the wearability of the device, in-situ non-invasive detection of vascular morphology parameters was achieved, making up for the lack of vascular morphology perception in existing wearable hemodynamic monitoring devices.

[0020] Improved monitoring accuracy: By acquiring parameters such as blood vessel depth and inner diameter, the dimensionality of the multi-physics field transmission model across tissue layers was improved, the modeling uncertainty of the mapping between sensor signals and physiological parameters was reduced, and the measurement accuracy of hemodynamic parameters was improved.

[0021] It has practical advantages: it adopts all commercial components and flexible packaging design, taking into account the miniaturization, low power consumption and biocompatibility of the device, and can work continuously in non-clinical environments such as home and sports, and supports high-frequency health monitoring.

[0022] Balancing safety and economy: The temperature rise of thermal excitation in a single measurement is less than 8°C, which is harmless to the human body; compared with ultrasonic imaging solutions, it avoids the problems of high process complexity and high cost, and is easier to achieve large-scale application. Attached Figure Description

[0023] Figure 1 A schematic diagram of the heat conduction path around a blood vessel when a rectangular thermal excitation source thermally excites the blood vessel with different morphological parameters. Figure 2 A schematic diagram of the transient temperature response of the body surface within the range of the rectangular thermal excitation source when a blood vessel is thermally excited by the thermal excitation source. Figure 3 This is a schematic diagram showing the transient temperature response at a measuring point within the range of a rectangular thermal excitation source when a rectangular thermal excitation source thermally excites blood vessels with different morphological parameters. Figure 4 This is a schematic diagram showing the distribution of thermal relaxation characteristic parameters and the injective mapping relationship between blood vessel morphology parameters at various measuring points within the range of the thermal excitation source. Figure 5 Exploded view of the structure and schematic diagram of the electronic system of the in-situ detection module for blood vessel morphology parameters; Figure 6 A comparison of vascular parameter inversion results from the in-situ vascular morphology parameter detection module with ultrasound imaging results in an in vivo experiment; Figure 7 The thermal imaging results are from a single measurement process performed by the in-situ detection module for vascular morphology parameters in a live experiment. Figure 8 This is the battery discharge curve during the cyclic operation of the in-situ detection module for blood vessel morphology parameters.

[0024] Among them, 1. core detection module, 11. thermal excitation source, 12. temperature sensor array, 13. flexible substrate, 2. miniaturized electronic system, 3. flexible heat insulation layer, 4. lithium battery, 5. flexible packaging structure, 6. medical ultra-thin double-sided adhesive. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0026] This invention establishes a theory for inverting vascular morphology parameters based on the principle of heat transfer, quantitatively describes the relationship between the thermal relaxation characteristics of tissues near blood vessels and vascular morphology, and develops an in-situ detection module for vascular morphology parameters based on the principle of heat transfer, which interprets the detection results of thermal relaxation characteristic distribution into vascular morphology parameters.

[0027] Among them, the inversion theory of vascular morphological parameters based on the principle of heat transfer includes: such as Figure 1As shown, when the skin surface is subjected to thermal stimulation, blood flow significantly alters the heat conduction path near blood vessels, while areas far from blood vessels are almost unaffected. Using the steady-state temperature rise at each measuring point as a benchmark, the temperature rise curves at each measuring point are normalized. The time required for the normalized temperature rise curve to rise to 0.85 is defined as the local thermal relaxation time constant (τ). τ can then quantitatively characterize the local thermal relaxation rate. For example... Figure 2 As shown, the thermal relaxation rate within the area affected by vascular heat differs significantly from that outside the area; the closer to the blood vessel, the faster the thermal relaxation. Figure 3 As shown, the depth of a blood vessel (the distance between the upper edge of the vessel wall and the skin) H tube ) and inner diameter ( D tube This will change the thermal influence range of the blood vessel and the thermal relaxation rate at each measuring point within the thermal influence range. For example... Figure 4 As shown, the thermal relaxation time constant distribution curve on the entire measurement point array exhibits a stable injective mapping relationship with the vascular morphology parameters, which can provide an effective and convenient theoretical basis for inverting vascular morphology based on the detection results of tissue thermal response characteristics.

[0028] Based on an innovative theory of vascular morphology parameter inversion, this invention provides an in-situ detection device for vascular morphology parameters, such as... Figure 5 As shown, the device employs a multi-layered integrated architecture constructed entirely of commercially available components, primarily comprising a core detection module 1, a miniaturized electronic system 2, a flexible thermal insulation layer 3, a lithium battery 4, a flexible packaging structure 5, and medical ultra-thin double-sided adhesive 6. The core detection module 1 includes a thermal excitation source 11, a temperature sensor array 12, and a flexible substrate 13. The thermal excitation source 11 is a coiled resistance wire heater, which can be rectangular in shape, and its surface is covered with the flexible thermal insulation layer 3. The temperature sensor array 12 consists of multiple negative temperature coefficient thermistors arranged in a linear array. The flexible substrate 13 is a flexible printed circuit board, on which the linear temperature sensor array 12 and the miniaturized electronic system 2 are integrated. The entire assembly is encapsulated within the flexible packaging structure 5 to form a biocompatible interface, powered by a power supply component. A stable mechanical connection is established between the sensor module and the skin to be tested using the medical ultra-thin double-sided adhesive 6.

[0029] The aforementioned device achieves thermal excitation through precise power control of the heater via a miniaturized electronic system 2. The temperature signal is converted into an analog quantity by the temperature sensor array 12, and then the miniaturized electronic system 2 performs signal conversion and wireless transmission. The user terminal, based on the theory of vascular morphology parameter inversion according to the principle of heat transfer, realizes the analysis of temperature signals and the interpretation of vascular parameters.

[0030] Among them, the vascular morphology parameter inversion theory based on the principle of heat transfer quantifies the thermal relaxation rate of the skin near blood vessels and establishes a mapping relationship between the thermal response signal of the skin near blood vessels after thermal excitation and vascular morphology parameters, providing a theoretical basis for the in-situ detection module of vascular morphology parameters based on the principle of heat transfer. For example... Figure 1-4 As shown, when the skin surface is subjected to thermal stimulation, blood flow significantly alters the heat conduction path near blood vessels, while locations far from blood vessels are almost unaffected. After normalizing the temperature response process at each measuring point and extracting thermal relaxation features, thermal relaxation feature distribution curves can be collected across the entire measuring point array. The depth of the blood vessel (the distance between the upper edge of the vessel wall and the skin) is also considered. H tube ) and inner diameter ( D tube This will change the thermal influence range of the blood vessel and the thermal relaxation rate at each measuring point within the thermal influence range. Verification has shown that the thermal relaxation characteristic distribution curves across the entire measuring point array exhibit a stable injective mapping relationship with the blood vessel morphology parameters, providing a theoretical basis for the inversion of blood vessel morphology parameters.

[0031] The following detailed description is provided through specific embodiments.

[0032] Example 1 A device for in-situ detection of vascular morphological parameters based on heat transfer principles, see [link / reference]. Figure 1 and 5 The system includes a core detection module 1, a miniaturized electronic system 2, a flexible heat insulation layer 3, a power supply component (a lithium battery 4 in this embodiment), a flexible packaging structure 5, and medical ultra-thin double-sided adhesive tape 6. The core detection module 1 comprises a thermal excitation source 11, a temperature sensor array 12, and a flexible substrate 13. The temperature sensor array 12 and the miniaturized electronic system 2 are integrated on the surface of the flexible substrate 13, and the entire assembly is encapsulated within the flexible packaging structure 5 to form a biocompatible interface. It is powered by a lithium battery, and a stable mechanical connection is established between the sensor module and the skin to be tested using the medical ultra-thin double-sided adhesive tape 6.

[0033] In this embodiment, the thermal excitation source 11 is a coiled resistance wire heater with dimensions of 2×20 mm. 2 The planar heating unit and the temperature sensor array 12 contain a linear array of 15 high-precision temperature measurement points to perform the functions of applying thermal excitation to the skin and detecting thermal response. In this embodiment, the flexible substrate 13 and the circuit processing substrate can be copper-clad PI flexible circuit boards (Cu / PI / Cu = 12μm / 12.5μm / 12μm), and the circuit forming method is selected based on the laser engraving process of the laser circuit stencil (Proto Laser U4, LPKF).

[0034] In this embodiment, the coiled resistance wire heater can be directly formed on a copper-clad PI flexible circuit board substrate (i.e., flexible substrate 13) by laser engraving. The linewidth of the resistance wire heater is 50μm, and the line spacing is 50μm. The dimension of the coiled resistance wire heater along the blood flow direction is set as length L, and the dimension in the direction orthogonal to the blood flow direction is set as width W. After flow robustness analysis of the sensor, when L is less than 2mm, the sensor has general adaptability to blood flow velocities greater than 2cm / s; after mounting error robustness analysis of the sensor, when W is greater than 20mm, the sensor has general adaptability to linear mounting errors with offset distances less than 4mm. The size combination of L=2mm and W=20mm is the optimal size combination for the coiled resistance wire heater.

[0035] In this embodiment, the temperature sensor array 12 employs negative temperature coefficient thermistors (NTCs). Due to the design requirements for electronic system integration and high resolution and precision in temperature field acquisition, the NTC can be a commercially available component (SDNT0603C103F3380FTF) in a 0201 (500μm long, 300μm wide) package. The temperature sensor array 12 can be arranged along the long side of the heater, with NTCs deployed at 1mm intervals in the near-field region (|position|≤4mm) and at 2mm intervals in the far-field region (4mm<|position|≤9mm), enabling temperature sampling across an 18mm span using 15 NTC measurement points.

[0036] In this embodiment, the flexible thermal insulation layer 3 is made of porous vacuum silicon or SiO2 aerogel with a thickness of 3 mm, both of which have a thermal conductivity as low as 0.012 W / m. -1 K -1 This achieves shielding against environmental thermal noise.

[0037] In this embodiment, see Figure 5 Miniaturized electronic system 2 is an integrated electronic system, comprising a BLE-WiFi dual-mode SoC, a 16-bit Σ-Δ ADC, and a power module. The BLE-WiFi dual-mode SoC is an ESP32-C3FH4, and the ADC is an integrated ADC module AD7124-8BCPZ with 16 single-ended inputs. The power module includes a charge pump for voltage conversion and an electronic switch for controlling heating power. The charge pump is a TPS60500DGSR, and the electronic switch is a TPS22908YZTR. Control signals are obtained from the SoC's GPIO pins. Miniaturized electronic system 2 completes the conversion of temperature response signals and wireless transmission to the user terminal.

[0038] In this embodiment, the flexible encapsulation structure 5 is encapsulated with silicone elastomer and synthesized using PDMS. The medical ultrathin double-sided adhesive 6 is 3M 1524. Both have strong biocompatibility and are commonly used in the encapsulation of biosensors and the mechanical connection of human-machine interfaces.

[0039] In this embodiment, a lithium battery of model UFX351423 (3.7V, 90mAh, UFX) is used as the power supply component to power the system.

[0040] The method for in-situ detection of vascular morphological parameters using the above-mentioned device includes the following steps: 1) Apply harmless thermal stimulation to the skin surface to be tested using a rectangular thermal excitation source 11 (long side length 20mm, orthogonal to the blood vessel axis); Figure 1 The diagram shows the heat conduction path around blood vessels when a rectangular thermal excitation source thermally excites blood vessels with different morphological parameters. The left diagram shows the core detection module 1 located on the skin above the blood vessel, and the right diagram shows the heat conduction path of the heat flux to large and small blood vessels. As can be seen from the diagram, when the skin surface is thermally excited, the blood flow significantly changes the heat conduction path in the area near the blood vessel, while the area away from the blood vessel is almost unaffected.

[0041] 2) The dynamic evolution of the temperature field is acquired in real time through the temperature sensor array 12; Figure 2 This diagram illustrates the transient temperature response of the body surface within the range of a rectangular thermal excitation source when a blood vessel is thermally excited. The diagram shows that the temperature field exhibits temporal and spatial anisotropy; for example, in… X Location = 0mm X A At point 1, continuous heating for 60 seconds resulted in a temperature increase of 5K; continuous heating for 600 seconds resulted in a temperature increase of 0.08K. However, at point 2, continuous heating for 600 seconds resulted in a temperature increase of 0.08K. X Location = 4mm X B At point 60 seconds, the temperature rises by 8K; after heating for 600 seconds, the temperature rises by 1.03K. 3) Based on the temperature field evolution information, predict the steady state of the temperature field and calculate the thermal relaxation time constant τ at each measuring point; specifically: Based on the normalization processing and thermal relaxation feature extraction of the temperature response process at each measuring point, thermal relaxation feature distribution curves are collected across the entire measuring point array. In this embodiment, the normalization process involves dividing the temperature response curve at each measuring point by a single value, which represents the steady-state temperature rise at the corresponding measuring point for each temperature rise curve. This maps the temperature distribution data from 0 to x °C of the original temperature rise curves to normalized temperature distribution data from 0 to 1. In this embodiment, the thermal relaxation feature is the local thermal relaxation time constant at each measuring point. The thermal relaxation time constant (τ) is a quantitative representation of the local thermal relaxation rate, representing the time required for the normalized temperature rise curve to rise to 0.85. The thermal relaxation rate within the vascular thermal influence range differs significantly from that outside the range; the closer the location is to the blood vessel, the faster the thermal relaxation, and therefore the smaller the thermal relaxation time constant.

[0042] 4) Based on the distribution pattern of the thermal relaxation time constant τ obtained in step 3), a multidimensional response relationship between vascular morphology parameters and thermal relaxation time is established, specifically as follows: In this embodiment, the depth of the blood vessel (the distance between the upper edge of the inner wall of the blood vessel and the skin) H tube ) and inner diameter ( D tube This will change the thermal influence range of the blood vessel and the thermal relaxation rate at each measuring point within the thermal influence range. The distribution curve of the thermal relaxation time constant on the entire measuring point array exhibits a stable injective mapping relationship with the vascular morphological parameters. Figure 3 This diagram illustrates the transient temperature response at a measuring point within the range of a rectangular thermal excitation source when a blood vessel with different morphological parameters is thermally excited by the source; the left figure shows the inner diameter of the blood vessel. D tube The graphs show the normalized temperature rise versus thermal excitation time at 2mm, 5mm, and 8mm, respectively. It can be seen from the graphs that at a fixed measuring point X... B (H) Tube In the case of D = 1mm), as D Tube Gradually decreasing from 8mm to 2mm, X B The value of τ at point τ shows a significant increasing trend (τ d8 =37s→τ d5 =50s→τ d2 = 78s) The right image shows the depth of the blood vessel. H tube The graphs show the normalized temperature rise versus thermal excitation time for 1mm, 2mm, and 3mm respectively. From the graphs, it can be seen that when D... Tube When fixed at 5mm, the height of the vascular bundle (H) varies. Tube The thickness was gradually increased from 1mm to 3mm. B The τ value at the point changes from 50s (τ)h1 Increased to 63s (τ) h2 ) and 82s (τ h3 ), respectively compared to τ h1 26.0% and 64.0% higher.

[0043] Figure 4 This is a schematic diagram showing the distribution of thermal relaxation characteristic parameters and the injective mapping relationship between vascular morphology parameters at various measuring points within the range of the thermal excitation source. As can be seen from the figure, different combinations of HTube and DTube correspond to unique τ distribution curve patterns, thus realizing the decoupling analysis of vascular morphology parameters and epidermal thermal relaxation characteristics.

[0044] In the process of obtaining the injective mapping relationship between vascular morphology parameters and thermal relaxation time, compensation for the misalignment of the sensor and vascular structure is performed based on the principle of virtual heat source. Specifically, a miniaturized electronic system 2 performs precise power control of the thermal excitation source 11 to achieve thermal excitation. The temperature sensor array 12 detects changes in ambient temperature, and its resistance value changes with temperature to generate an analog voltage signal. This signal is conditioned by a PGA (Programmable Gain Amplifier) ​​and then sent to a 16-bit Σ-Δ ADC (AD7124-8BCPZ) for high-precision analog-to-digital conversion. Its multi-channel single-ended input structure supports simultaneous acquisition of multiple temperature signals. The converted digital signal is transmitted to a BLE-WiFi dual-mode SoC (ESP32-C3FH4) via an SPI interface. The SoC is responsible for data processing and protocol encapsulation, and wirelessly transmits the temperature data to the user terminal (such as a mobile phone or cloud platform) through its built-in BLE or WiFi module. The charge pump (TPS60500DGSR) provides stable voltage conversion, while the electronic switch (TPS22908YZTR), controlled by the SoC's GPIO-PWM signal, precisely adjusts the heater power to achieve closed-loop temperature control. The entire system is highly integrated, realizing integrated intelligent monitoring from temperature sensing, signal conversion, data processing to wireless transmission.

[0045] 5) The user terminal uses a neural network model to invert and calculate the diameter and depth of blood vessels, enabling in-situ detection of blood vessel morphology parameters. In this embodiment, the signal processing and blood vessel morphology parameter inversion programs of the user terminal can be developed using LabVIEW.

[0046] The above-mentioned in-situ detection device for vascular morphology parameters was used in an in vivo experiment, and compared with conventional ultrasound imaging, as follows: In this embodiment, as Figure 6-7 As shown, four typical segments of the basilic vein on the forearm of two healthy volunteers can be selected for in vivo experiments. Specifically, Figure 6 The results show the morphological measurements of four typical venous segments in the forearm of a healthy volunteer under controlled environmental conditions (23±0.5℃). Figure 7 The results show a comparison between the vascular morphology parameters derived from the neural network and the ultrasound measurement parameters in four typical venous segments.

[0047] The comparison shows that the vessel depth inversion error is ≤0.3 mm (Position A / Position B), and the diameter measurement error is ≤0.5 mm (Position C / Position D). It is noteworthy that the venous vessel diameter measurement at Position C exhibits high dispersion, which stems from vessel deformation caused by sensor mounting pressure under low venous pressure conditions.

[0048] Experiments show that, using this embodiment, except for the need to improve the stability of large blood vessel diameter measurement, the measurement accuracy of other parameters reaches the level of medical imaging equipment (depth error ≤ 0.3 mm, diameter error ≤ 0.5 mm), verifying the application potential of the blood vessel morphology inversion theory and supporting sensing module proposed in this invention in hemodynamic monitoring.

[0049] The power consumption performance of the above-mentioned in-situ detection device for vascular morphology parameters was tested: like Figure 8 The diagram shows the battery discharge curve during the cyclic operation of the aforementioned in-situ vascular morphology parameter detection device. A UFX351423 (3.7V, 90mAh, UFX) lithium battery powers the system. The entire system maintains effective operation for 6050 seconds (54 complete cycles) before the 3.3V cutoff voltage, with a single cycle energy consumption of 1.85%. Considering the device's size and low power consumption, this device can be deployed in most fully integrated wearable biosensor devices without significantly affecting other modules.

[0050] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0051] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A device for in-situ detection of vascular morphological parameters based on the principle of heat transfer, characterized in that, include: The core detection module (1) includes a thermal excitation source (11), a temperature sensor array (12), and a flexible substrate (13), wherein the temperature sensor array is disposed on the flexible substrate; The miniaturized electronic system (2) is connected to the core detection module (1) and is used to control the power output of the thermal excitation source (11) and receive the signal from the temperature sensor array (12); A flexible packaging structure (5) encapsulates the core detection module (1) and the miniaturized electronic system (2) to form a biocompatible interface.

2. The in-situ detection device for vascular morphological parameters based on the principle of heat transfer according to claim 1, characterized in that, The thermal excitation source (11) is a coiled resistance wire heater, the surface of which is covered with a flexible heat insulation layer (3). The temperature sensor array (12) consists of multiple negative temperature coefficient thermistors arranged in a linear array to form multiple high-precision temperature measurement points; The flexible substrate (13) is a flexible printed circuit board, on which a temperature sensor array (12) and a miniaturized electronic system (2) are integrated.

3. The in-situ detection device for vascular morphological parameters based on the principle of heat transfer according to claim 1, characterized in that, The miniaturized electronic system (2) includes a BLE-WiFi dual-mode SoC, a 16-bit Σ-Δ ADC, and a power module.

4. The in-situ detection device for vascular morphological parameters based on the principle of heat transfer according to claim 1, characterized in that, The flexible encapsulation structure (5) is a silicone elastomer.

5. The in-situ detection device for vascular morphological parameters based on the principle of heat transfer according to claim 1, characterized in that, It also includes a power supply component that supplies power to the core detection module (1) and the miniaturized electronic system (2).

6. The in-situ detection device for vascular morphological parameters based on the principle of heat transfer according to claim 1, characterized in that, It also includes medical ultra-thin double-sided tape (6), which is used to mechanically connect the device to the skin to be tested.

7. A method for in-situ detection of vascular morphological parameters using the device described in any one of claims 1-6, characterized in that, Includes the following steps: Thermal excitation is applied to the surface of the skin to be tested using a thermal excitation source (11); Temperature response signals at different locations on the skin surface are collected in real time using a temperature sensor array (12); Based on the temperature field evolution information, predict the steady state of the temperature field and calculate the thermal relaxation time constant τ at each measuring point; Based on the distribution law of thermal relaxation time constant τ, a multidimensional response relationship between vascular morphological parameters and thermal relaxation time is established. Vascular morphology parameters are obtained through inversion calculation using a neural network model.

8. The method for in-situ detection of vascular morphological parameters based on the principle of heat transfer according to claim 7, characterized in that, The thermal relaxation time constant τ is calculated as follows: the temperature rise curve is normalized based on the steady-state temperature rise value at each measuring point, and the time taken for the normalized temperature rise curve to rise to 0.85 is the thermal relaxation time constant. The vascular morphology parameters include vascular depth and vascular diameter.

9. The method for in-situ detection of vascular morphological parameters based on the principle of heat transfer according to claim 7, characterized in that, In the process of establishing the multidimensional response relationship between vascular morphology parameters and thermal relaxation time, the non-aligned mounting state of the sensor and vascular structure is compensated based on the principle of virtual heat source. Specifically, the thermal excitation is achieved by the precise power control of the thermal excitation source (11) through the miniaturized electronic system (2). The temperature signal is converted into an analog quantity through the temperature sensor array (12), and the analog quantity is transmitted to the miniaturized electronic system (2). The miniaturized electronic system (2) completes the conversion of the temperature response signal and the wireless transmission to the user terminal.

10. The method for in-situ detection of vascular morphological parameters based on the principle of heat transfer according to claim 7, characterized in that, Obtaining vascular morphology parameters through inversion calculation of neural network model means: the user terminal uses LabVIEW to compile a miniaturized electronic system (2) to transmit information, realize the analysis of temperature signals and the parsing of vascular parameters.

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