Ultrasonic range finder for esophageal atresia

Abstract

The invention relates to the technical field of medical apparatus and instruments, and discloses an esophageal atresia ultrasonic range finder which is used for measuring long segment deletion type esophageal atresia of infants and comprises an ultrasonic array module, a navigation coupling module and a signal processing module. According to the method, a high-resolution blind end three-dimensional form is obtained through an intracavity self-adaptive fitting scanning and synthetic aperture focusing technology, the optimal measurement basis is dynamically determined by fusing spatial attitude data, the shortest path distance of a three-dimensional space is finally calculated, and measurement errors of in-vitro ultrasound and two-dimensional images are avoided; real-time measurement data and spatial position information are fused and presented, so that an intuitive form and length change trend is provided for a doctor, and the confidence and accuracy of a treatment decision are enhanced; automatic processes from data acquisition and processing to result output are integrated, the operation difficulty and the human intervention intensity are reduced, objective, quantitative and visual decision support is provided for clinicians to evaluate the curative effect of the esophageal extension surgery and select the optimal surgery opportunity, and the diagnosis and treatment efficiency and repeatability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, and particularly relates to an ultrasonic range finder for esophageal atresia. BACKGROUND

[0002] Congenital esophageal atresia is a serious digestive tract malformation in newborns, and the treatment of long-segment absence type is particularly difficult, which often needs to be preceded by esophageal tension lengthening to promote the growth of the esophagus. In this treatment process, accurate, safe and repeatable monitoring of the changes in the length of the esophageal atresia is crucial for evaluating the lengthening effect and selecting the optimal operation time.

[0003] At present, the main distance measuring methods in clinical practice have obvious limitations: X-ray esophagography and radiographic distance measuring method have ionizing radiation, which is not suitable for infants who need long-term and multiple monitoring; although the conventional ultrasonic distance measuring method has no radiation, it is easily disturbed by the lung gas and respiratory activity of infants, and the measurement accuracy is difficult to guarantee. Therefore, the prior art cannot realize the precise three-dimensional reconstruction of the proximal and distal blind end shape and the accurate calculation of the spatial distance in the esophageal lumen without radiation, resulting in a lack of reliable and intuitive data support for doctors in evaluating the lengthening effect and formulating subsequent surgical plans. SUMMARY

[0004] The present application aims to provide an ultrasonic range finder for esophageal atresia to solve the technical problems raised in the background.

[0005] To achieve the above-mentioned purpose, the present application discloses the following technical solutions: an ultrasonic range finder for esophageal atresia for measuring long-segment absence type esophageal atresia in infants, comprising: an ultrasonic array module comprising a flexible catheter and an expandable stent provided at the distal end of the flexible catheter, the expandable stent carrying a plurality of ultrasonic sensors; the expandable stent has a storage state and an expanded state, in the expanded state, the expandable stent radially expands to make each ultrasonic sensor self-adaptively fit the morphologically variable esophageal wall of the infant; a navigation coupling module comprising a micro inertial measurement unit, a contact force sensor array and at least one magnetic navigation marker point provided at the distal end of the flexible catheter; the navigation coupling module is configured to sense the three-dimensional spatial posture of the ultrasonic array module in the esophagus and the contact force distribution with the esophageal wall in real time; a signal processing module, which is signal-connected with the ultrasonic array module and the navigation coupling module, and is configured to: based on a multi-angle echo sequence acquired by the ultrasonic array module in an expanded state of the expandable stent, reconstruct a high-resolution morphological profile of proximal esophageal blind end and distal esophageal blind end by using a synthetic aperture focusing technique optimized for sparse aperture; fuse the high-resolution morphological profile with three-dimensional spatial posture data provided by the navigation coupling module, dynamically determine a reference plane for length measurement; and on the reference plane, calculate a three-dimensional spatial shortest path distance between the proximal esophageal blind end and the distal esophageal blind end, and output the three-dimensional spatial shortest path distance as an esophageal atresia length.

[0006] Optionally, the determination manner of the reference plane comprises: identifying a lowest point of the proximal esophageal blind end and a highest point of the distal esophageal blind end based on the high-resolution morphological profile; taking a straight line connecting the lowest point and the highest point as a normal vector, and combining real-time pitch angle and roll angle data measured by the micro inertial measurement unit, calculating and determining an optimal measurement plane with a largest contact area with the proximal esophageal blind end and the distal esophageal blind end as the reference plane.

[0007] Optionally, when reconstructing the high-resolution morphological profile, the signal processing module is further configured to perform a fistula identification and bypassing process, the fistula identification and bypassing process comprising: extracting echo signals of different angles from the same spatial position in the high-resolution morphological profile from the multi-angle echo sequence; calculating a cross-correlation coefficient between the echo signals of different angles, and determining that the corresponding spatial position is a structural abnormal region when the cross-correlation coefficient is lower than a first preset threshold; extracting a center frequency downshift amount of the echo signal of the structural abnormal region, and confirming that the structural abnormal region is a suspected tracheoesophageal fistula when the downshift amount exceeds a second preset threshold; automatically planning a measurement path bypassing the suspected tracheoesophageal fistula region when calculating the three-dimensional spatial shortest path distance.

[0008] Optionally, after confirming the suspected tracheoesophageal fistula, the signal processing module is further configured to start a targeted contrast enhancement analysis, the targeted contrast enhancement analysis comprising: controlling the ultrasonic sensor to emit a group of linear frequency modulation coded pulses towards the suspected tracheoesophageal fistula region; After pulse compression processing is performed on the received echo signals from the suspected tracheoesophageal fistula region, inverse scattering tomography reconstruction is performed using a time reversal mirror algorithm to generate a two-dimensional cross-sectional image of the suspected tracheoesophageal fistula region. The connectivity and edge features of the two-dimensional cross-sectional image are analyzed, and when the image features meet the preset fistula shape standard, the region is finally confirmed as a tracheoesophageal fistula, and the high-resolution shape profile is updated, and the suspected tracheoesophageal fistula region is marked as a confirmed fistula; when the image features do not meet the preset fistula shape standard, the suspected identification of the region is removed.

[0009] Optionally, the calculation process of the three-dimensional space shortest path distance includes: A contact force uniformity coefficient is calculated based on the data of the contact force sensor array. When the contact force uniformity coefficient is higher than a set value, it is determined that the coupling state of the sensor and the esophageal wall is good, and a preset muscle tissue sound speed value is selected for distance calculation; when the contact force uniformity coefficient is lower than the set value, it is determined that the coupling state is not good, and a preset mixed tissue sound speed value is selected for distance calculation. Based on the selected sound speed value, the time interval from ultrasonic wave transmission to reception is converted into actual physical distance. The converted multiple actual physical distance data are used to perform a path search algorithm on the reference plane to calculate the three-dimensional space shortest path distance.

[0010] Optionally, the expandable support of the ultrasonic array module is driven by a micro lead screw transmission mechanism, and the signal processing module is further configured to perform support expansion control, the support expansion control including: Multiple contact force data fed back by the contact force sensor array are received, and the variance of the multiple contact force data is calculated. The calculated variance value is compared with a preset target variance range, and the deviation is calculated as the input of a PI controller. The PI controller generates a control signal according to the deviation, and the control signal is defined as the number of steps and the direction that the micro lead screw transmission mechanism needs to move. The control signal is sent to the micro lead screw transmission mechanism to drive it to rotate, so as to adjust the expansion diameter of the expandable support.

[0011] Optionally, the micro lead screw transmission mechanism includes a lead screw, a nut matched with the lead screw, and a micro stepping motor, the nut is hinged with the support connecting rod of the expandable support; the thread of the lead screw is a triangular thread with self-locking characteristics, and the output shaft of the micro stepping motor is rigidly connected with the lead screw through a shaft coupling.

[0012] Optionally, a display unit is further included, configured to present the position of the ultrasonic array module in the esophagus, the high-resolution morphological profile and the calculated esophageal atresia length in real time based on the output data of the signal processing module.

[0013] Optionally, the signal processing module is further configured to predict the esophageal atresia length trend based on historical measurement data, comprising: storing the esophageal atresia length data obtained from previous measurements in chronological order to form a time series data set; fitting the time series data set through an autoregressive integrated moving average model to build a prediction model; extrapolating the predicted values of the esophageal atresia length at one or more future time points based on the prediction model.

[0014] Optionally, the signal processing module is further configured to perform safety monitoring, comprising: monitoring the spatial peak time average sound pressure of the ultrasonic sensor and the maximum contact force value of the contact force sensor array in real time; inputting the spatial peak time average sound pressure and the maximum contact force value into a preset tissue damage risk model to calculate a tissue stress risk value; when the tissue stress risk value exceeds a preset safety threshold, reducing the ultrasonic wave emission power to 50% of the original power and triggering an audible and visual alarm.

[0015] Beneficial effects: The esophageal atresia ultrasonic range finder of the present application is harmless and suitable for long-term and repeated monitoring of infants. Secondly, through intracavitary adaptive fitting scanning and synthetic aperture focusing technology, high-resolution blind end three-dimensional morphology is obtained, and spatial attitude data is fused to dynamically determine the optimal measurement reference. Finally, the three-dimensional space shortest path distance is calculated, avoiding the measurement error of extracorporeal ultrasound and two-dimensional image. At the same time, real-time measurement data and spatial position information are fused and presented, providing intuitive morphology and length trend for doctors, enhancing the confidence and accuracy of treatment decision-making. In addition, the automatic process from data acquisition, processing to result output is integrated, reducing the operation difficulty and human intervention intensity, providing objective, quantitative and visual decision support for clinicians to evaluate the efficacy of esophageal lengthening surgery and select the best operation opportunity, improving the diagnosis and treatment efficiency and repeatability. BRIEF DESCRIPTION OF DRAWINGS

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural block diagram of the ultrasonic rangefinder for esophageal atresia provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the principle of the miniature lead screw transmission mechanism provided in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0019] In this document, the term "comprising" is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] This embodiment provides a method such as Figure 1 The ultrasonic rangefinder for esophageal atresia shown is used for measuring long-segment esophageal atresia in infants and young children. It includes an ultrasonic array module, a navigation coupling module, and a signal processing module. In detail: The ultrasound array module includes a flexible catheter (which may be made of biocompatible polyurethane or silicone material, with a diameter of about 2-3 mm) and a deployable support (which may be made of nickel-titanium alloy shape memory metal braid) located at the distal end of the flexible catheter. The deployable support carries multiple ultrasound sensors (which may be high-frequency miniature ultrasound transducers in the prior art, such as piezoelectric ceramic sensors with a center frequency of 20-40 MHz). The deployable support has a retracted state and an deployed state. In the deployed state, the deployable support expands radially to allow each ultrasound sensor to adaptively conform to the shape of the infant's esophagus wall, which varies greatly.

[0021] a navigation coupling module, which is provided at the distal end of the flexible catheter and includes a miniature inertial measurement unit (a six-axis IMU using MEMS technology, including a three-axis accelerometer and a three-axis gyroscope), a contact force sensor array (a matrix of micro-strain-based pressure sensors), and at least one magnetic navigation marker (a neodymium-iron-boron permanent magnet); the navigation coupling module is configured to sense the three-dimensional spatial pose of the ultrasonic array module within the esophagus and the contact force distribution with the esophageal wall in real time.

[0022] a signal processing module (implemented using an embedded FPGA or a DSP processor), which is in signal connection with the ultrasonic array module and the navigation coupling module; the signal processing module is configured to: based on the multi-angle echo sequence obtained by the ultrasonic array module in the expanded state of the expandable stent, reconstruct the high-resolution morphological profile of the proximal esophageal blind end and the distal esophageal blind end using a synthetic aperture focusing technique (SAFT) optimized for a sparse aperture (the optimization algorithm is weighted delay-and-sum WDS, which adjusts the delay weight of each sensor echo to compensate for the phase difference of the sparse elements and improve the lateral resolution to ≤0.1 mm); fuse the high-resolution morphological profile with the three-dimensional spatial pose data provided by the navigation coupling module (sampling rate 100 Hz, real-time update of catheter X / Y / Z coordinates and pitch / roll angles) to dynamically determine the reference plane for length measurement; and on the reference plane, calculate the three-dimensional spatial shortest path distance between the proximal esophageal blind end and the distal esophageal blind end (the path search uses the Dijkstra algorithm, with a grid accuracy of 0.01 mm, avoiding the esophageal wall and abnormal areas), and output the path distance with the shortest three-dimensional spatial distance as the esophageal atresia length.

[0023] Based on the above, the embodiment realizes stable coupling of the sensor and the esophageal wall through the expandable stent, solving the signal attenuation problem caused by poor contact in traditional ultrasonic measurement. The complex esophageal morphology of infants (such as congenital stenosis and bending) can be adaptively expanded by the super-elasticity of the nickel-titanium alloy of the expandable stent, the small diameter in the accommodation state reduces the difficulty of insertion, and the ultrasonic sensor is in direct contact with the esophageal wall after expansion, reducing the energy attenuation of ultrasonic in the air gap. The use of multi-angle echo sequence combined with synthetic aperture focusing technology improves the imaging resolution under the condition of sparse array, and can accurately reconstruct the complex three-dimensional morphology of the esophageal blind end. By fusing inertial navigation data and morphological profile information, the optimal measurement reference plane is dynamically determined, overcoming the error caused by angle deviation in traditional two-dimensional measurement methods. Finally, the atresia length is calculated based on the three-dimensional spatial shortest path algorithm, which has higher accuracy and reliability than traditional methods, providing accurate quantitative evaluation data for clinical use.

[0024] In one embodiment, the determination of the reference plane includes: Based on the high-resolution morphological profile, the lowest point of the proximal esophageal blind end and the highest point of the distal esophageal blind end are identified by using the Canny edge detection algorithm (gradient threshold set to 50, lag threshold low 40 / high 80, to ensure accurate identification of the blind end edge) (the lowest point is defined as the edge point of the proximal blind end closest to the stomach side, and the highest point is defined as the edge point of the distal blind end closest to the throat side); The straight line connecting the lowest point and the highest point is taken as the normal vector (the normal vector direction tends to follow the longitudinal axis of the esophagus), and the real-time pitch angle (range -15°~15°, reflecting the forward and backward inclination of the esophagus) and roll angle (range -10°~10°, reflecting the left and right rotation of the esophagus) data measured by the miniature inertial measurement unit (sampling rate 100 Hz, taking the average value within 50 ms to reduce noise) are combined, and the profile intersection area calculation method (the intersection area between the candidate plane and the blind end profile is calculated, and the pixel area of the intersection area is calculated) is used to calculate and determine an optimal measurement plane with the largest contact area between the proximal esophageal blind end and the distal esophageal blind end as the reference plane (the contact area must be ≥80% of the total profile area of the blind end, to ensure that the main measurement area is covered).

[0025] Based on the above, the present embodiment realizes intelligent optimization of the measurement reference plane through the fusion of geometric feature point recognition and spatial attitude data. The lowest point and the highest point of the blind end are selected as the reference features, ensuring that the measurement plane can cover the effective contact area of the two blind ends to the greatest extent. Combined with real-time attitude data, the plane direction is dynamically adjusted, effectively compensating for the measurement deviation caused by changes in patient position or catheter movement. This adaptive reference plane determination method improves the repeatability and accuracy of length measurement, and is suitable for esophageal blind end structures with complex and variable morphology.

[0026] In one embodiment, when reconstructing the high-resolution morphological profile, the signal processing module is further configured to perform a fistula identification and bypass process, which includes: From the multi-angle echo sequence, extract echo signals of different angles from the same spatial position in the high-resolution morphological profile; Calculate the cross-correlation coefficient (value range 0-1, reflecting signal similarity) between echo signals of different angles using the Pearson correlation coefficient algorithm. When the cross-correlation coefficient is lower than a first preset threshold (such as 0.5, determined based on a number of normal esophageal tissue echo data), it is determined that the corresponding spatial position is a structural abnormal area; Extract the center frequency downshift of the echo signal of the structural abnormal area using Fast Fourier Transform (FFT) (such as 20-40 MHz for normal tissue, and the abnormal area may be downshifted to 15-30 MHz), and when the downshift exceeds a second preset threshold (such as 5 MHz), the structural abnormal area is confirmed as a suspected tracheoesophageal fistula; The measurement path is automatically planned to bypass the suspected tracheoesophageal fistula region when calculating the shortest path distance in three-dimensional space.

[0027] Based on the above, the embodiment realizes accurate detection of tracheoesophageal fistula through multi-angle echo coherence analysis and spectral feature recognition. The cross-correlation coefficient can effectively distinguish the area where the tissue structure continuity is destroyed, and the downward shift of the center frequency reflects the change of the acoustic characteristics of the tissue. The double criterion mechanism greatly reduces the false positive rate and ensures sensitive detection of small fistulas. The automatic path planning function avoids the measurement path passing through the fistula region, ensuring the accuracy of the measurement and preventing further damage to the fragile tissue, thereby improving the safety of the examination.

[0028] In a further optional embodiment, after confirming the suspected tracheoesophageal fistula, the signal processing module is further configured to start a targeted contrast enhancement analysis, which includes: The ultrasonic sensor closest to the suspected tracheoesophageal fistula region (such as 2-3 sensors selected to ensure coverage of the fistula region) is controlled to emit a set of linear frequency modulation coded pulses (such as LFM pulses, time width 10 μs, bandwidth 5-10 MHz, peak power ≤5 mW, to avoid high energy damaging the tissue); After pulse compression processing (compression ratio 10:1, compressing 10 μs pulses to 1 μs, improving the distance resolution to ≤0.1 mm) of the received echo signals from the suspected tracheoesophageal fistula region, inverse scattering tomography reconstruction is performed using the time reversal mirror algorithm (TRM, number of iterations 5 times, compensating for tissue propagation distortion) to generate two-dimensional cross-sectional images of the suspected tracheoesophageal fistula region; The connectivity and edge features of the two-dimensional cross-sectional images are analyzed (such as whether there is a tubular connected structure connecting the esophageal cavity and the tracheal cavity, and whether the edge is smooth and continuous), and when the image features meet the preset fistula shape standard, the region is finally confirmed as a tracheoesophageal fistula, and the high-resolution shape profile is updated, and the suspected tracheoesophageal fistula region is marked as a confirmed fistula; when the image features do not meet the preset fistula shape standard, the suspected identification of the region is removed.

[0029] Based on the above, the embodiment further improves the accuracy of fistula diagnosis through targeted contrast enhancement technology. Linear frequency modulation coded pulses combined with pulse compression processing improve the signal-to-noise ratio and resolution of the system. The time reversal mirror algorithm can realize the spatio-temporal focusing of sound waves and is suitable for imaging in complex media. The final confirmation is made by analyzing the morphological features of the image, establishing a complete diagnosis process from suspected to confirmed, and providing a reliable imaging basis for clinical treatment.

[0030] In one embodiment, the calculation process of the shortest path distance in three-dimensional space includes: The contact force uniformity coefficient is calculated based on the data of the contact force sensor array (the calculation formula is the ratio of the standard deviation to the average of the sensor readings); When the contact force uniformity coefficient is higher than a set value, it is determined that the coupling state of the sensor and the esophageal wall is good, and a preset muscle tissue sound speed value (set as 1540 m / s, which is the average sound speed of human esophageal muscle tissue, a clinical standard value) is selected for distance calculation; when the contact force uniformity coefficient is lower than the set value, it is determined that the coupling state is not good, and a preset mixed tissue sound speed value (set as 1480-1520 m / s, which is dynamically adjusted according to the size of the gap) is selected for distance calculation; Based on the selected sound speed value v, the time interval from the emission to the reception of the ultrasonic wave is converted into the actual physical distance by the formula d = v x t / 2 (t is the time interval measured by the timer of the signal processing module from the emission to the reception of the ultrasonic wave); The converted multiple actual physical distance data (200 distance data are collected by each sensor, and the mean value is taken after removing the abnormal values) are used to perform a path search algorithm (such as Dijkstra algorithm, grid step length 0.01 mm, obstacle area set as esophageal wall and fistula) on the reference plane, and the shortest path distance in three-dimensional space is calculated.

[0031] Based on the above, the embodiment realizes adaptive compensation of sound speed through contact force feedback, effectively solving the measurement error caused by the change of tissue coupling state. The contact force uniformity coefficient can accurately reflect the fitting quality of the sensor array and the esophageal wall, and the optimal sound speed value is selected according to different fitting states, which improves the accuracy of time-distance conversion. Combined with the three-dimensional path search algorithm, it is ensured that the final measurement result reflects the real shortest spatial distance between the two blind ends, rather than the projected distance.

[0032] In one embodiment, the expandable support of the ultrasonic array module is driven by a micro-screw transmission mechanism, and the signal processing module is further configured to perform support expansion control, which includes: Receiving multiple contact force data fed back by the contact force sensor array, and calculating the variance of the multiple contact force data (calculated by the calculation formula in the prior art); Comparing the calculated variance value with a preset target variance range (such as 0.01-0.05 N 2 ) and calculating the deviation (the difference between the two) as the input of the PI controller (proportional-integral controller, the parameters are determined by the Ziegler-Nichols tuning method: proportional coefficient Kp = 2, integral coefficient Ki = 0.5, sampling period 0.02 s); The PI controller generates a control signal (control signal U=Kp x e+Ki x ∫edt, e is the value of the deviation, output range -10~+10 steps, negative step is contraction, positive step is expansion) according to the deviation, which is defined as the number of steps and direction (such as each step corresponds to the change of 0.1mm in the diameter of the expanded support, +1 step increases the diameter by 0.1mm, -1 step reduces the diameter by 0.1mm) that the micro-screw drive mechanism needs to move; The control signal is sent to the micro-screw drive mechanism to drive it to rotate, so as to adjust the expansion diameter of the expandable support, so that the contact force variance value approaches the target variance range.

[0033] Based on the above, the embodiment realizes the accurate adjustment of the support expansion through closed-loop control. The control strategy based on the contact force variance can ensure that the sensor array maintains a moderate and uniform contact force with the esophageal wall, avoiding both signal attenuation due to insufficient contact force and damage to the fragile esophageal tissue caused by excessive contact force. The PI controller ensures the stability and rapid response capability of the system, so that the support can adapt to esophageal cavities of different diameters.

[0034] In a further optional embodiment, the micro-screw drive mechanism includes a screw, a nut cooperating with the screw, and a micro-step motor, the nut is hinged to the support link of the expandable support; the thread of the screw is a triangular thread with self-locking characteristics, and the output shaft of the micro-step motor is rigidly connected to the screw through a coupling. It should be noted that the micro-screw drive mechanism can be designed in any structure form in the prior art. For those skilled in the art and those skilled in the mechanical field, the specific mechanical structure can be determined according to the micro-screw drive mechanism example shown in Figure 2 The corresponding principles include: ①The micro-step motor is the power source of the mechanism, which has the characteristics of precise angular displacement control (for example, 1.8 degrees per step). By controlling the number of steps and direction of the motor, the expansion diameter of the support can be accurately controlled. The self-locking characteristic of the stepping motor also provides additional holding torque when power is off.

[0035] ②The coupling is used to connect the motor output shaft and the screw, ensuring power transmission without reverse clearance. This rigid connection avoids the elastic deformation and transmission error that may occur when using a flexible coupling, ensuring a strict correspondence between the rotation angle of the motor and the linear displacement of the nut.

[0036] ③Screw rod (trigonometric self-locking thread), the thread of the screw rod adopts a trigonometric thread (such as a metric thread) with a large thread angle, the equivalent friction angle of the thread is large, when the static friction resistance is greater than the axial component force generated by the rebound force of the support or the compression force of the tissue, the mechanism is self-locked, which means that the position of the support is locked firmly without active driving of the motor, and the support will not spontaneously contract or expand, thereby ensuring the stability and safety during the measurement. The self-locking principle of the trigonometric thread is that the thread angle of the trigonometric thread is 60°, the helix angle is 3°, and the torque generated by the reaction force (≤0.5N) of the esophageal stent is small, and the helix angle is ≤ the friction angle (5°), so even if the motor is powered off, the nut will not move due to the reaction force, ensuring the stability of the position of the stent after expansion.

[0037] ④The nut is used in cooperation with the screw rod to convert the rotary motion of the screw rod into the linear motion of the nut, and the linear displacement of the nut is the direct action for controlling the expansion of the stent.

[0038] ⑤The hinge point is a support connecting rod connecting the nut and the expandable stent, and the hinge design allows the support connecting rod to change the angle under the push of the nut, thereby efficiently converting the linear thrust of the nut into the radial expansion force of the stent, and at the same time, the hinge structure enables the stent to better adapt to the internal mechanical transmission of the catheter in the curved esophageal shape.

[0039] ⑥The support connecting rod of the expandable stent is an execution component of the transmission mechanism, when the nut moves linearly, the support connecting rod is pushed or pulled through the hinge point, like scissors, to open or close, and finally realize the radial expansion and contraction of the entire stent.

[0040] In combination Figure 2 It can be seen that the miniature screw rod transmission mechanism provides precise control through the stepping motor, ensures error-free transmission through the rigid coupling, guarantees position stability through the self-locking thread, and realizes efficient power conversion through the hinged connecting rod, which together constitutes an accurate, reliable, and safe expansion control unit. It ensures that the ultrasonic sensor array can stably adhere to the fragile esophageal wall of the infant with optimal contact force, thereby laying a solid mechanical foundation for obtaining high-quality ultrasonic echo signals.

[0041] Based on the above, the mechanical design of the miniature screw rod transmission mechanism ensures the reliability and accuracy of the transmission mechanism. The self-locking property of the trigonometric thread prevents accidental contraction of the stent due to tissue reaction force during the measurement, ensuring the stability of the measurement. The coupling eliminates the transmission gap, ensuring the accurate correspondence between the rotation angle of the stepping motor and the expansion diameter of the stent. The hinge design makes the stent expansion process smoother and adapts to irregular tissue surfaces.

[0042] In an embodiment, the esophageal atresia ultrasonic range finder further comprises a display unit (optionally a 10.1-inch high-definition touch screen with a resolution of 1920x1200 and a brightness of ≥500 cd / m 2 , suitable for the strong light environment of the operating room), which is configured to: based on the output data of the signal processing module, use the augmented reality (AR) technology in the prior art to present in real time the position of the ultrasonic array module in the esophagus (three-dimensional coordinates generated by magnetic navigation data), high-resolution morphological profile (reconstructed esophageal and blind end profile), and calculated esophageal atresia length, and can also display the final confirmed tracheoesophageal fistula area.

[0043] Based on the above, the embodiment realizes the visualization of the measurement results through the integrated display system. The real-time superimposed display function provides the operator with intuitive spatial relationship and morphological information, improving the accuracy and safety of the operation. The special label of the fistula area helps the clinician to focus on the abnormal area, providing an important reference for treatment decision-making. This integrated display scheme simplifies the operation process and improves the diagnosis and treatment efficiency.

[0044] In an embodiment, the signal processing module is further configured to predict the esophageal atresia length trend based on historical measurement data, including: Store the esophageal atresia length data obtained from each measurement in chronological order (e.g., every 7 days, consistent with the growth cycle of infants' esophagus, measure once a week) to form a time series data set (e.g., 5.2 mm on day 0, 4.8 mm on day 7, 4.3 mm on day 14); Fit the time series data set using an autoregressive integrated moving average model (ARIMA model, parameters determined by AIC criterion: p=2 (number of autoregressive terms), d=1 (number of differences), q=1 (number of moving average terms), goodness of fit R 2 ≥0.9) to construct a prediction model (parameters estimated using the least squares method); Based on the prediction model, extrapolate to calculate the predicted value of the esophageal atresia length at one or more future time points (preset to 7 days, 14 days, and 21 days in the future, which are commonly used observation periods in clinical practice).

[0045] Based on the above, the embodiment realizes the quantitative prediction of the treatment effect through time series analysis. The ARIMA model can accurately capture the time dependence and trend characteristics of esophageal growth, providing an objective growth kinetics evaluation for the clinic. The prediction function based on historical data helps doctors optimize treatment plans, judge the best surgery time in advance, avoid unnecessary treatment delays, and implement personalized treatment plans.

[0046] In an embodiment, the signal processing module is further configured to perform safety monitoring, including: Real-time monitoring of spatial peak temporal average sound pressure (SPTA sound pressure, real-time acquisition by power meter) of ultrasonic sensor and maximum contact force value (real-time feedback by sensor) of contact force sensor array; Input spatial peak temporal average sound pressure and maximum contact force value into preset tissue damage risk model based on von Mises stress criterion (model formula: risk value , Tissue stress risk value, value range [0, 1], the closer R is to 1, the higher the risk of esophageal tissue (especially fragile mucosa of infants) damage is; SPTA is the spatial peak temporal average sound pressure (unit: mW / cm 2 ) monitored by the ultrasonic sensor in real time, reflecting the risk of ultrasonic thermal damage; SPTA is the preset ultrasonic sound pressure safety threshold, the value needs to meet the FDA medical ultrasonic safety standard, such as 100 mW / cm 2 ; Maximum contact force value (unit: N) monitored by the contact force sensor array in real time, reflecting the risk of mechanical compression damage; The preset contact force safety threshold is determined based on infant esophageal wall tolerance test, and exceeding this value is easy to cause mucosal tear, such as taking the value as 0.5 N; 0.6 and 0.4 are weight coefficients, which are determined based on clinical damage risk statistics, and the incidence of ultrasonic thermal damage (about 5%) is slightly higher than that of mechanical damage (about 3%), so the thermal damage related item (SPTA item) has higher weight), calculate the tissue stress risk value; in the tissue damage risk model, (von Mises stress Three-dimensional stress, generated by SPTA sound pressure (thermal stress) and contact force (mechanical stress), Von Mises stress (equivalent stress, unit: MPa), used to convert complex stress state in three-dimensional space into a single scalar to evaluate the overall mechanical damage risk of the tissue; 、 、 Three-dimensional principal stress (unit: MPa) borne by the esophageal tissue, generated by two parts, namely ① ultrasonic thermal stress: converted from SPTA sound pressure (sound energy is absorbed by the tissue to become heat energy, resulting in thermal expansion of the tissue and generating stress); mechanical compression stress: converted from Local compression stress generated by the contact between the sensor and the esophageal wall; the denominator of the formula Standardization coefficient for converting three-dimensional principal stress to equivalent stress, ensuring that the result is consistent with the damage criterion of uniaxial tensile stress; When the tissue stress risk value exceeds the preset safety threshold (e.g., set to 0.8, based on 50 infant tissue tolerance tests, R>0.8 indicates a significant risk of injury), the ultrasonic emission power is reduced to 50% of the original power (the sensor driving voltage is adjusted from 5V to 2.5V by the signal processing module), and an audible and light alarm is triggered.

[0047] The embodiment ensures the safety of the diagnosis and treatment process through real-time monitoring of multiple parameters. The tissue damage risk model can accurately assess the risk of tissue damage under complex load conditions, making it more scientific and reliable than single-parameter monitoring. The automatic power reduction mechanism and audible and light alarm system provide timely safety warnings for operators, effectively preventing tissue damage caused by improper device operation, and are suitable for infant patients with fragile tissues.

[0048] In summary, the esophageal atresy ultrasonic range finder of the embodiment is harmless and suitable for long-term and repeated monitoring of infants. Through intracavitary adaptive fitting scanning and synthetic aperture focusing technology, high-resolution blind-end three-dimensional morphology is obtained, and spatial attitude data is fused to dynamically determine the optimal measurement reference. The three-dimensional space shortest path distance is finally calculated, avoiding the measurement errors of external ultrasound and two-dimensional images. Real-time measurement data and spatial position information are fused and presented, providing doctors with intuitive morphology and length change trends, enhancing the confidence and accuracy of treatment decisions. In addition, the automatic process from data acquisition, processing to result output is integrated, reducing the operation difficulty and human intervention intensity, providing objective, quantitative and visual decision support for clinicians to evaluate the efficacy of esophageal lengthening surgery and select the best surgical timing, improving the diagnosis and treatment efficiency and repeatability.

[0049] In the embodiments provided by the present application, it should be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, code, or any appropriate combination thereof. For hardware implementation, the processor can be implemented in one or more of the following: application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For software implementation, the procedures described herein can be implemented with associated hardware to perform the procedures described herein. In implementation, the procedures described above can be stored in a computer readable storage medium or transmitted as one or more instructions or code on a computer readable storage medium. The computer readable storage medium includes a computer storage medium and a communication medium, and the communication medium includes any medium that facilitates transfer of a computer program from one place to another. The storage medium can be any available medium that can be accessed by a computer. The computer readable storage medium can include, but is not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage medium, or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0050] Finally, it should be noted that the above-described embodiments are merely exemplary of the application and should not be used in a limiting sense. Rather, the description is intended to cover any alternatives, modifications, and equivalents, which can be made to the embodiments described herein, by those who are skilled in the art in the spirit and principles of the present application.

Claims

1. An ultrasonic rangefinder for measuring esophageal atresia in infants and young children, characterized in that, include: An ultrasound array module includes a flexible catheter and a deployable support disposed at the distal end of the flexible catheter. The deployable support carries multiple ultrasound sensors. The deployable support has a retracted state and an deployed state. In the deployed state, the deployable support expands radially to allow each ultrasound sensor to adaptively conform to the shape of the infant's esophagus. The navigation coupling module includes a miniature inertial measurement unit, a contact force sensor array, and at least one magnetic navigation marker point disposed at the distal end of the flexible catheter; the navigation coupling module is configured to sense the three-dimensional spatial orientation of the ultrasound array module in the esophagus and the distribution of contact force with the esophageal wall in real time. A signal processing module, which is signal-connected to the ultrasound array module and the navigation coupling module, is configured to: based on the multi-angle echo sequence acquired by the ultrasound array module in the deployed state of the deployable stent, reconstruct high-resolution morphological contours of the proximal and distal blind ends of the esophagus using synthetic aperture focusing technology optimized for sparse apertures; fuse the high-resolution morphological contours with three-dimensional spatial attitude data provided by the navigation coupling module to dynamically determine a reference plane for length measurement; and calculate the three-dimensional shortest path distance between the proximal and distal blind ends of the esophagus on the reference plane, and output the shortest path distance as the esophageal atresia length.

2. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, The methods for determining the reference plane include: Based on the high-resolution morphological contour, the lowest point of the proximal blind end of the esophagus and the highest point of the distal blind end of the esophagus are identified. Using the straight line connecting the lowest point and the highest point as the normal vector, and combining the real-time pitch and roll angle data measured by the micro inertial measurement unit, an optimal measurement plane with the largest contact area with the proximal blind end and the distal blind end of the esophagus is calculated and determined as the reference plane.

3. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, In reconstructing the high-resolution morphological contour, the signal processing module is also configured to perform a fistula identification and bypass process, which includes: From the multi-angle echo sequence, echo signals from different angles at the same spatial location in the high-resolution morphological contour are extracted; Calculate the cross-correlation coefficient between the echo signals at different angles. When the cross-correlation coefficient is lower than a first preset threshold, determine that the corresponding spatial location is a structurally abnormal region. Extract the center frequency shift of the echo signal corresponding to the structurally abnormal region. When the shift exceeds a second preset threshold, the structurally abnormal region is confirmed as a suspected tracheoesophageal fistula. When calculating the shortest path distance in the three-dimensional space, a measurement path is automatically planned to bypass the suspected tracheoesophageal fistula area.

4. The ultrasonic rangefinder for esophageal atresia according to claim 3, characterized in that, After confirming the suspected tracheoesophageal fistula, the signal processing module is further configured to initiate targeted contrast-enhanced imaging analysis, which includes: Control the ultrasonic sensor directed toward the suspected tracheoesophageal fistula area to emit a set of linear frequency modulated coded pulses; After pulse compression processing of the received echo signal from the suspected tracheoesophageal fistula area, inverse scattering tomography reconstruction is performed using a time-reversal mirror algorithm to generate a two-dimensional cross-sectional image of the suspected tracheoesophageal fistula area. The connectivity and edge features of the two-dimensional cross-sectional image are analyzed. When the image features meet the preset fistula morphology standards, the region is finally confirmed as a tracheoesophageal fistula, and the high-resolution morphological contour is updated to mark the suspected tracheoesophageal fistula region as a confirmed fistula. When the image features do not meet the preset fistula morphology standards, the suspected marking of the region is removed.

5. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, The calculation process for the shortest path distance in three-dimensional space includes: The contact force uniformity coefficient is calculated based on the data from the contact force sensor array. When the contact force uniformity coefficient is higher than the set value, it is determined that the coupling state between the sensor and the esophageal wall is good, and a preset muscle tissue sound velocity value is selected for distance calculation; when the contact force uniformity coefficient is lower than the set value, it is determined that the coupling state is poor, and a preset mixed tissue sound velocity value is selected for distance calculation. Based on the selected sound speed value, the time interval between the transmission and reception of the ultrasonic wave is converted into the actual physical distance. Using the converted data of multiple actual physical distances, a path search algorithm is executed on the reference plane to calculate the shortest path distance in the three-dimensional space.

6. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, The deployable support of the ultrasonic array module is driven by a miniature lead screw transmission mechanism. The signal processing module is also configured to perform support deployment control, which includes: Receive multiple contact force data fed back from the contact force sensor array, and calculate the variance of the multiple contact force data; The calculated variance value is compared with a preset target variance range, and the deviation is calculated as the input of the PI controller. The PI controller generates a control signal based on the deviation, and the control signal is defined as the number of steps and direction that the micro screw transmission mechanism needs to move. The control signal is sent to the micro screw drive mechanism to drive it to rotate, thereby adjusting the unfolding diameter of the unfoldable bracket.

7. The ultrasonic rangefinder for esophageal atresia according to claim 6, characterized in that, The miniature lead screw transmission mechanism includes a lead screw, a nut that mates with the lead screw, and a miniature stepper motor. The nut is hinged to the support rod of the deployable bracket. The lead screw has a triangular thread with self-locking characteristics, and the output shaft of the miniature stepper motor is rigidly connected to the lead screw through a coupling.

8. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, It also includes a display unit configured to: based on the output data of the signal processing module, display in real time the position of the ultrasound array module in the esophagus, the high-resolution morphological contour, and the calculated esophageal atresia length.

9. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, The signal processing module is also configured to predict the trend of esophageal atresia length changes based on historical measurement data, including: The esophageal atresia length data obtained from each measurement are stored in chronological order to form a time series dataset. A prediction model is constructed by fitting the time series dataset using an autoregressive integral moving average model. Based on the prediction model, the predicted length of esophageal atresia at one or more future time points is extrapolated and calculated.

10. The ultrasonic rangefinder for esophageal atresia according to claim 1, characterized in that, The signal processing module is also configured to perform security monitoring, which includes: Real-time monitoring of the spatial peak time-averaged sound pressure of the ultrasonic sensor and the maximum contact force value of the contact force sensor array; The spatial peak time-averaged sound pressure and the maximum contact force value are input into a preset tissue damage risk model to calculate the tissue stress risk value; When the tissue stress risk value exceeds the preset safety threshold, the ultrasonic emission power is reduced to 50% of the original power and an audible and visual alarm is triggered.

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