Circuit structure with multi-path adaptive conversion circuit

Abstract

The present disclosure provides a circuit structure with a multi-path adaptive conversion circuit, which is used for receiving an echo signal and processing the echo signal to output a digital signal, the echo signal being an analog signal gradually attenuated over time, the circuit structure comprising an adaptive conversion circuit and a time gain amplifier (TGC), the adaptive conversion circuit comprising an operational amplifier, a gain controller, and an analog-to-digital converter, the operational amplifier being configured to receive an amplified signal amplified by the time gain amplifier (TGC) on the echo signal; the gain controller being configured to control the gain of the operational amplifier according to the intensity of the amplified signal so that the adaptive conversion circuit provides adaptive gain according to the intensity of the amplified signal; and the analog-to-digital converter being configured to convert the signal output by the operational amplifier into a digital signal, the analog-to-digital converter having different time delays so that the multi-path adaptive conversion circuit has different sampling time points.

Description

[0001] This application is a divisional application of the patent application filed on December 31, 2019, with application number 2019114090701 and invention title "Image Processing Method for Intravascular Ultrasound System". Technical Field

[0002] This disclosure generally relates to the field of medical devices, and more specifically to a circuit structure with a multi-channel adaptive switching circuit for use in an intravascular ultrasound system. Background Technology

[0003] Currently, high-frequency intravascular ultrasound imaging systems are mainly used clinically to guide PCI procedures, especially after stent implantation, to determine whether the stent has adhered well to the vessel wall. Poor apposition can lead to thrombosis, significantly increasing the probability of restenosis within the vessel. In severe cases, it can cause stent displacement, obstructing blood flow and endangering the patient's life.

[0004] The high-frequency intravascular ultrasound system includes an image processing unit, a retraction device, and a high-frequency intravascular ultrasound catheter. The high-frequency intravascular ultrasound system sends an excitation electrical signal through the retraction system or the controller in the image processing unit. The ultrasound transducer, when excited, vibrates, converting the excitation electrical signal into an ultrasound signal (ultrasound wave) which is then emitted. The ultrasound signal propagates within the blood and tissues of the body and is reflected by the tissues. The ultrasound transducer receives the reflected ultrasound signal (ultrasound echo), converts it into an electrical signal, and transmits it back to the retraction system and the image processing unit for processing via signal lines.

[0005] In practical applications, doctors typically use intravascular ultrasound images to determine if the vessel wall and stent boundaries align properly, thus assessing stent apposition. However, because stent ultrasound reflection is a strong reflected echo signal, while normal vascular tissue signal is a scattered weak echo signal, without any processing, intravascular ultrasound images may show stent signal saturation or excessively dark tissue signal. Stent signal saturation reduces stent resolution, potentially leading to an overestimation of stent size (similar to overexposed photography), affecting the assessment of stent apposition. Conversely, excessively dark tissue signal, while not indicating stent signal saturation, results in a dark image where vascular tissue information may not be fully presented. Summary of the Invention

[0006] This disclosure was made in view of the above-mentioned state of the prior art, and its purpose is to provide an image processing method for an intravascular ultrasound system that can prevent signal saturation and excessively dark tissue signals.

[0007] Therefore, this disclosure provides an image processing method for an intravascular ultrasound system, wherein the intravascular ultrasound system transmits and acquires ultrasound signals through an intravascular ultrasound catheter. The method comprises: acquiring the ultrasound signal acquired by the intravascular ultrasound catheter and converting it into an echo signal, wherein the echo signal is an analog signal that gradually decays over time; amplifying the echo signal using a time gain amplifier (TGC) according to a preset time gain curve to obtain an amplified signal, wherein the time gain curve gradually increases over time; inputting the amplified signal into a multiplexed adaptive conversion circuit, wherein the adaptive conversion circuit has different sampling time points and provides adaptive gain based on the intensity of the amplified signal; and the adaptive conversion circuit converts the amplified signal into a digital signal, and fuses the digital signals output by the adaptive conversion circuit to generate a target signal as the output signal.

[0008] In this disclosure, the ultrasound signal acquired by the intravascular ultrasound catheter is converted into an echo signal and then amplified. The amplified echo signal is then input into a multiplex adaptive conversion circuit. Finally, the digital signal output by the adaptive conversion circuit is fused into the target signal. In this case, the adaptive conversion circuit can identify the intensity of the input echo signal and adjust the gain, thereby avoiding excessively high or low gain and reducing the possibility of adverse conditions such as signal saturation and excessively dark tissue signals.

[0009] Alternatively, in the image processing method disclosed herein, the digital signal output by the adaptive conversion circuit is input to a field-programmable array (FPGA) and fused, and the FPGA generates the target signal based on the digital signals from each adaptive conversion circuit. In this case, the FPGA can generate the target signal based on the input digital signal, thereby enabling the target signal to be displayed as an image on a display screen.

[0010] Additionally, in the image processing method disclosed herein, optionally, the adaptive conversion circuit includes an operational amplifier, a gain controller for controlling the gain of the operational amplifier, a filter for filtering the signal output by the operational amplifier and generating a filtered signal, and an analog-to-digital converter for converting the filtered signal into the digital signal. In this case, the gain controller can control the gain of the operational amplifier, thereby controlling the gain of the operational amplifier according to the strength of the input signal, and then converting the amplified signal into a digital signal through the filter and the analog-to-digital converter.

[0011] Furthermore, in the image processing method disclosed herein, optionally, in the adaptive conversion circuit, the gain controller controls the gain of the operational amplifier based on a preset threshold and the intensity of the amplified signal. If the amplified signal is greater than the threshold, the gain of the amplified signal is reduced; if the amplified signal is less than the threshold, the gain of the amplified signal remains unchanged. In this case, the gain controller can reduce signals above the threshold, thereby preventing signal saturation.

[0012] Furthermore, in the image processing method disclosed herein, optionally, in the adaptive conversion circuit, the gain controller controls the gain of the operational amplifier according to the intensity gain curve and the intensity of the amplified signal, and the gain controller adjusts the gain of the amplified signal according to the gain corresponding to the intensity of the amplified signal in the intensity gain curve. In this case, the gain controller can adjust the gain of the amplified signal according to the intensity gain curve, thereby avoiding signal saturation.

[0013] Additionally, in the image processing method disclosed herein, optionally, the analog-to-digital converter in the adaptive conversion circuit has a preset delay. In this case, the analog-to-digital converters in different adaptive conversion circuits have different delays, thereby enabling the reception of amplified signals at different time points, thus increasing the depth of the image.

[0014] Alternatively, in the image processing method disclosed herein, the multi-channel adaptive conversion circuit may include three independent adaptive conversion circuits that receive the amplified signal. This allows for the acquisition of amplified signals at three different time points.

[0015] Additionally, in the image processing method disclosed herein, optionally, the field-programmable array obtains the target signal based on a first digital signal, a second digital signal, and a third digital signal, wherein the target signal satisfies:

[0016] F=ka×fa(t)+kb×fb(t)+kc×fc(t)……Equation (1)

[0017] Where F represents the target signal, fa(t) represents the first digital signal, ka represents the weight of the first digital signal, fb(t) represents the second digital signal, kb represents the weight of the second digital signal, fc(t) represents the third digital signal, and kc represents the weight of the third digital signal. Therefore, the target signal can be synthesized according to the above formula.

[0018] Additionally, in the image processing method disclosed herein, a bandpass filter may optionally be provided between the time gain amplifier and the multiplexer adaptive conversion circuit. This reduces noise in the amplified signal.

[0019] Additionally, in the image processing method disclosed herein, optionally, a stent is disposed on the wall of the blood vessel, and the echo signal includes an ultrasound signal reflected from the stent and an ultrasound signal reflected from the blood vessel. In this case, by using an adaptive conversion circuit to adjust the gain of the ultrasound signal reflected from the stent and the ultrasound signal reflected from the blood vessel, the resolution of the ultrasound system image can be improved.

[0020] According to this disclosure, an image processing method for an intravascular ultrasound system can be provided that can prevent signal saturation and excessively dark tissue signals. Attached Figure Description

[0021] Embodiments of this disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings, in which:

[0022] Figure 1 This is a schematic diagram illustrating the structure of an intravascular ultrasound system according to an embodiment of the present disclosure.

[0023] Figure 2 This is a flowchart illustrating an image processing method for an intravascular ultrasound system according to an embodiment of the present disclosure.

[0024] Figure 3 (a) is a schematic intravascular ultrasound image illustrating a case where the stent is not fully adhered to the vessel wall according to an embodiment of the present disclosure.

[0025] Figure 3 (b) is a schematic intravascular ultrasound image showing the complete apposition of the stent according to an embodiment of the present disclosure.

[0026] Figure 4 This is a schematic diagram of a blood vessel cross-section showing the direction of intravascular ultrasound emission according to an embodiment of the present disclosure.

[0027] Figure 5 This is a time gain graph showing the time gain of a time gain amplifier according to an embodiment of the present disclosure.

[0028] Figure 6 This is a schematic diagram of the circuit structure of an image processing method for an intravascular ultrasound system according to an embodiment of the present disclosure.

[0029] Figure 7 This is a timing diagram illustrating an analog-to-digital converter according to an embodiment of the present disclosure.

[0030] Explanation of icon numbers:

[0031] 1…Intravascular ultrasound system, 11…Blood vessel, 12…Stent. Detailed Implementation

[0032] The present disclosure will now be described in further detail with reference to the accompanying drawings and specific embodiments. In the drawings, the same components or components having the same function are denoted by the same symbols, and repeated descriptions of them are omitted.

[0033] Figure 1 This is a schematic diagram showing the structure of an intravascular ultrasound system 1 according to an embodiment of the present disclosure. Figure 2 This is a flowchart illustrating an image processing method for an intravascular ultrasound system 1 according to an embodiment of the present disclosure.

[0034] like Figure 1 , Figure 2 As shown, in this embodiment, the image processing method for an intravascular ultrasound system 1 disclosed herein includes: the intravascular ultrasound system 1 can transmit and acquire ultrasound signals via an intravascular ultrasound catheter (sometimes also called an "ultrasound catheter") and convert them into echo signals, which can be analog signals that gradually decay over time. Subsequently, the echo signals can be amplified by a time gain amplifier (TGC) according to a preset time gain curve to obtain an amplified signal, whereby the time gain curve can gradually increase over time. Then, the amplified signal can be input into a multiplexed adaptive conversion circuit, which can have different sampling time points and can provide adaptive gain based on the intensity of the amplified signal. Finally, the adaptive conversion circuit can convert the amplified signal after amplification into a digital signal, and the digital signals output by the adaptive conversion circuit are fused to generate a target signal as the output signal.

[0035] In this disclosure, the ultrasound signal acquired by the intravascular ultrasound catheter is converted into an echo signal and then amplified. The amplified echo signal is then input into a multiplex adaptive conversion circuit. Finally, the digital signal output by the adaptive conversion circuit is fused into the target signal. In this case, the adaptive conversion circuit can identify the intensity of the input echo signal and adjust the gain, thereby avoiding excessively high or low gain and reducing the possibility of adverse conditions such as signal saturation and excessively dark tissue signals.

[0036] In some examples, the intravascular ultrasound system 1 may include an image processing host, a retraction device, and an intravascular ultrasound catheter.

[0037] In some examples, the operation of the intravascular ultrasound system 1 is as follows: First, a medical guidewire is inserted into the target area of ​​the blood vessel, such as the lesion area, through the puncture site of the blood vessel 11. Then, an ultrasound catheter is threaded onto the medical guidewire and pushed into the target area of ​​the blood vessel, while ensuring that the ultrasound transducer (probe) of the ultrasound catheter is at the distal end of the target area of ​​the blood vessel. This ensures complete detection of the target area of ​​the blood vessel.

[0038] Next, the image of the target vascular region is verified on the image processing host. After verification, keeping the ultrasound catheter and medical guidewire stationary, the retraction device is activated to automatically retract the flexible drive shaft (imaging core shaft) from the vascular lesion at a certain speed. During the retraction process, the ultrasound transducer can be rotated to measure the condition of the target vascular region (e.g., lumen and wall) by rotating the flexible drive shaft.

[0039] Finally, after withdrawing the flexible drive shaft, keep the position of the medical guidewire unchanged, withdraw the ultrasound catheter first, and then withdraw the medical guidewire.

[0040] In addition, to prevent thrombus formation in blood vessel 11 and its impact on the imaging performance of the ultrasound catheter, heparin needs to be administered before the medical guidewire and ultrasound catheter are inserted into blood vessel 11. Furthermore, nitroglycerin needs to be injected into the coronary artery before imaging based on the ultrasound transducer's detection signal to prevent coronary artery spasm.

[0041] In this embodiment, the image processing method for the intravascular ultrasound system 1 disclosed herein includes an image processing method for transmitting and acquiring ultrasound signals through an intravascular ultrasound catheter. In other examples, the intravascular ultrasound catheter may transmit ultrasound signals via an ultrasound transducer. Based on the above-described ultrasound signal acquisition method, such as... Figure 2 As shown, in step S100, the ultrasound signal acquired by the intravascular ultrasound catheter can be obtained and converted into an echo signal. In some examples, the intravascular ultrasound catheter can receive the ultrasound signal and convert it into an electrical signal via an ultrasound transducer. Thus, the echo signal can be obtained via the ultrasound transducer and transmitted to the image processing host.

[0042] In this embodiment, the echo signal can be an analog signal that gradually decays over time. In some examples, the echo signal is an electrical signal. Therefore, the ultrasonic signal can be converted into an electrical signal for easier processing.

[0043] Figure 3 (a) is a schematic intravascular ultrasound image showing a case where the stent 12 is not fully adhered to the vessel wall according to an embodiment of the present disclosure.

[0044] Figure 3(b) is a schematic intravascular ultrasound image showing the complete apposition of the stent 12 according to an embodiment of the present disclosure.

[0045] like Figure 3 (a) Figure 3 As shown in (b), in some examples, a stent 12 can be placed in the wall of the blood vessel 11. In this case, when the stent 12 can expand the blood vessel 11 and be fixed within the blood vessel 11, smooth blood flow can be maintained, avoiding the effects of thrombosis. Specifically, when the stent 12 is in Figure 3 In case (b), the stent 12 fits tightly against the wall of the blood vessel 11, providing good support; when the stent 12 is in Figure 3 In case (a), the stent 12 does not fit well with the blood vessel 11, which may lead to more adverse symptoms.

[0046] In some examples, the echo signal may include an ultrasound signal reflected from the stent 12 and an ultrasound signal reflected from the blood vessel 11. In this case, the gain of the ultrasound signal reflected from the stent 12 and the ultrasound signal reflected from the blood vessel 11 is adjusted by an adaptive conversion circuit (described later), thereby improving the resolution of the ultrasound system image.

[0047] Figure 4 This is a schematic cross-sectional view of blood vessel 11 showing the direction of intravascular ultrasound emission according to an embodiment of the present disclosure.

[0048] like Figure 4 As shown, in some examples, the ultrasound waves emitted by the intravascular ultrasound catheter during retraction can be scanned as illustrated. Specifically, ultrasound waves are emitted along the W direction of the scan line by an ultrasound transducer located at the center of the blood vessel, while the intravascular ultrasound catheter carrying the ultrasound transducer rotates in the L direction. Thus, the ultrasound transducer can emit and receive signals from all positions along the scan line, allowing for a more complete detection of the condition within blood vessel 11. In other examples, the intravascular ultrasound catheter can also rotate in the opposite direction of the L direction. Furthermore, in some examples, the ultrasound transducer may not be located at the center of blood vessel 11. This also allows for complete detection of the condition within blood vessel 11. In other examples, the intravascular ultrasound catheter can control the number of scan lines per revolution of the ultrasound transducer by controlling the excitation frequency of the ultrasound transducer. Therefore, the resolution of the final ultrasound image can be improved by increasing the number of scan lines per revolution of the ultrasound transducer.

[0049] Specifically, ultrasound signals attenuate rapidly within tissue. For example, a 60MHz ultrasound signal attenuates by as much as 24dB at a far-field distance of 4mm (distance from the ultrasound signal emission point) in tissue (dB = 20log10(Areceive / Aemit), where A is the ultrasound signal voltage amplitude). In human tissue, the signal dynamic range is 30-40dB (dB = 20log10(Amaximum / Aminimum), where A is the ultrasound signal voltage amplitude at various points in the tissue). Because the acoustic impedance of the scaffold 12 is much greater than that of human tissue, the near-field signal from the scaffold 12 is often 20-30dB higher than the tissue signal (dB = 20log10(Areceive / Aemit), where A is the ultrasound signal voltage amplitude). Therefore, in an ultrasound image that includes both the scaffold 12 and human tissue, the required dynamic range for the entire image may reach 50-70dB (the ultrasound signal is strongest at the scaffold 12 and weakest deep within the tissue). However, the grayscale range of intravascular ultrasound images is fixed at 0-255. An excessively large dynamic range means that the grayscale difference between each dB within the dynamic range is too small, resulting in poor resolution. In this case, without any processing, the intravascular ultrasound image may show stent 12 signal saturation or excessively dark tissue signal. As a result, stent 12 signal saturation and stent 12 resolution deterioration may lead to an overestimation of the stent 12's range (similar to overexposure in photography), affecting the judgment of stent 12 apposition. When the stent 12 is actually poorly apposed, it may be considered to be well apposition due to the deteriorated stent 12 resolution. Conversely, when the tissue signal is too dark, although the stent 12 signal is not saturated, the image is too dark, which may prevent the complete presentation of vascular tissue information.

[0050] Figure 5 This is a time gain graph showing the time gain of a time gain amplifier according to an embodiment of the present disclosure.

[0051] like Figure 5 As shown, in step S200, the image processing host can amplify the echo signal according to a preset time gain curve using a time gain amplifier (TGC) to obtain an amplified signal.

[0052] In this embodiment, the time gain curve gradually increases over time. In other words, the gain gradually increases over time. In some examples, such as... Figure 5 As shown, the depth reached by the ultrasonic signal is used as the horizontal axis, that is, the depth to which the ultrasonic wave propagates over time, and the magnitude of the gain is used as the vertical axis. When the time gain curve is in the effective depth part, time and gain are roughly positively correlated. The magnitude of the gain gradually increases with the increase of depth until it exceeds the effective depth, and then the magnitude of the gain becomes a horizontal straight line.

[0053] In some examples, a bandpass filter can be placed between the time gain amplifier and the adaptive multiplexing circuit. Specifically, the bandpass filter allows a specific frequency band between 10MHz and 90MHz to pass through. This reduces noise in the amplified signal. In some examples, a high-pass filter or a low-pass filter can also be placed between the time gain amplifier and the adaptive multiplexing circuit. This allows for more targeted filtering.

[0054] In step S300, the image processing host can input the amplified signal into the multiplexer adaptive conversion circuit. In other words, the time gain amplifier is connected to the multiplexer adaptive conversion circuit. This allows the amplified signal to be input into the adaptive conversion circuit, thereby obtaining a suitable gain. In some examples, the gain can be positive (amplification) or negative (decrease). In this case, when the gain is positive, increasing the gain increases the strength of the signal boost, and decreasing the gain decreases the strength of the signal boost; when the gain is negative, increasing the gain decreases the strength of the signal degrade, and decreasing the gain increases the strength of the signal degrade.

[0055] Figure 6 This is a schematic diagram of the circuit structure of an image processing method for an intravascular ultrasound system 1 according to an embodiment of the present disclosure.

[0056] like Figure 6 As shown, in some examples, the adaptive conversion circuit may include an operational amplifier, a gain controller for controlling the gain of the operational amplifier, a filter for filtering the signal output from the operational amplifier and generating a filtered signal, and an analog-to-digital converter (ADC) for converting the filtered signal into a digital signal. In this case, the gain controller can control the gain of the operational amplifier, thereby controlling the gain of the operational amplifier according to the strength of the input signal, and then converting the amplified signal into a digital signal through the filter and the ADC. In some examples, the filter may be a high-pass filter, a low-pass filter, or a band-pass filter.

[0057] In step S300, the adaptive conversion circuit can have different sampling time points. Specifically, after the ultrasound transducer of the intravascular ultrasound catheter emits ultrasound waves in a certain direction, within the effective reflection distance, from the time the reflected signal is received to the time the farthest reflected signal is received, the adaptive conversion circuit can acquire the reflected signal at any time point, i.e., the converted echo signal. Therefore, the resolution of the final ultrasound image can be improved by adjusting the number of samples taken by the adaptive conversion circuit and the interval between sampling points.

[0058] Figure 7 This is a timing diagram illustrating an analog-to-digital converter according to an embodiment of the present disclosure.

[0059] like Figure 7 As shown, in some examples, the analog-to-digital converter (ADC) in the adaptive conversion circuit has a preset delay. In this case, the ADCs in different adaptive conversion circuits have different delays, and thus the delay of the adaptive conversion circuit can be controlled by controlling the delay of the ADC. This allows the amplified signals at different time points to be received, such as the amplified signals at time points T1, T2, and T3 (see [reference]). Figure 7 This increases the image depth, i.e., the distance between the initial and final sampling points. In other examples, in multiplexed adaptive conversion circuits, the analog-to-digital converters can have the same sampling frequency. In this case, the adaptive conversion circuits differ only in their different delays, thus ensuring that the intervals between the sampling points acquired by the multiplexed adaptive conversion circuits are equal. Additionally, in some examples, the analog-to-digital converters between the adaptive conversion circuits can have different sampling frequencies. In this case, multiple sampling points can be formed by the difference in sampling frequencies, thus enabling the acquisition of multiple sampling points without setting a delay.

[0060] In some examples, the multiplexed adaptive converter circuit may include three independent adaptive converter circuits that receive amplified signals (see [reference]). Figure 6 Specifically, in adaptive conversion circuits, the operational amplifier, gain controller, and filter are all components with the same model number. Therefore, different adaptive conversion circuits can be distinguished based on the analog-to-digital converter. Figure 6 The diagram illustrates a three-channel adaptive conversion circuit (ADC1, ADC2, and ADC3). This allows for the acquisition of amplified signals at three time points. In other examples, multi-channel adaptive conversion circuits may include four, five, six, or more channels. This improves the resolution of the ultrasound images. Additionally, in some examples, the sampling frequency of the adaptive conversion circuit can be increased by increasing the sampling frequency of the analog-to-digital converter. This also improves the resolution of the ultrasound images.

[0061] In some examples, the adaptive conversion circuit can provide adaptive gain based on the strength of the amplified signal. In some examples, the strength of the amplified signal can be the voltage amplitude. Specifically, the larger the voltage amplitude, the stronger the amplified signal, and the smaller the voltage amplitude, the weaker the amplified signal.

[0062] In some examples, in adaptive switching circuits, the gain controller can adjust the gain of the operational amplifier based on a preset threshold and the strength of the amplified signal. If the amplified signal is greater than the threshold, the gain is reduced; if the amplified signal is less than the threshold, the gain remains constant. In this case, the gain controller can reduce signals above the threshold, thereby preventing signal saturation.

[0063] In some examples, in adaptive switching circuits, the gain controller can control the gain of the operational amplifier based on an intensity-gain curve (not shown) and the intensity of the amplified signal. The gain controller adjusts the gain of the amplified signal according to the gain corresponding to the intensity of the amplified signal in the intensity-gain curve. In this case, the gain controller can adjust the gain of the amplified signal according to the intensity-gain curve, thereby avoiding signal saturation. In other examples, the gain controller can continuously reduce the gain through negative feedback until the intensity of the amplified signal is less than a predetermined threshold.

[0064] In some examples, the intensity gain curve can be a step-like, linear, or nonlinear relationship.

[0065] In some examples, the adaptive conversion circuit can convert the amplified signal after gain into a digital signal. In this case, the amplified signal input to the adaptive conversion circuit is converted into a digital signal via an analog-to-digital converter, which facilitates the subsequent fusion of multiple amplified signals.

[0066] In step S400, the image processing host can fuse the digital signals output by the adaptive conversion circuits to generate a target signal as the output signal. Specifically, the image processing host can input the digital signals output by the adaptive conversion circuits into a field-programmable array (FPGA) and fuse them, and the FPGA generates the target signal based on the digital signals from each adaptive conversion circuit. In this case, the FPGA can generate the target signal based on the input digital signals, thereby enabling the target signal to be displayed on the display screen as an image.

[0067] In some examples, the field-programmable array obtains the target signal based on a first digital signal, a second digital signal, and a third digital signal, the target signal satisfying:

[0068] F=ka×fa(t)+kb×fb(t)+kc×fc(t)……Equation (1)

[0069] Where F represents the target signal, fa(t) represents the first digital signal, ka represents the weight of the first digital signal, fb(t) represents the second digital signal, kb represents the weight of the second digital signal, fc(t) represents the third digital signal, and kc represents the weight of the third digital signal. Therefore, the target signal can be synthesized according to the above formula.

[0070] In this embodiment, the first digital signal may come from ADC1, the second digital signal may come from ADC2, and the third digital signal may come from ADC3.

[0071] In some examples, the image processing host can display the target signal as an image on the screen. This allows the user to visually see the ultrasound image within the blood vessel 11.

[0072] While the present disclosure has been specifically described above in conjunction with the accompanying drawings and embodiments, it is to be understood that the above description does not limit the present disclosure in any way. Those skilled in the art can make modifications and variations to the present disclosure as needed without departing from its essential spirit and scope, and all such modifications and variations fall within the scope of the present invention.

Claims

1. A circuit structure with a multi-channel adaptive conversion circuit, used for receiving echo signals and processing the echo signals to output digital signals, characterized in that, The echo signal is an analog signal that gradually decays over time. The circuit structure includes a time gain amplifier (TGC) and a multiplexer adaptive conversion circuit. Each of the adaptive conversion circuits includes an operational amplifier, a gain controller, and an analog-to-digital converter. The operational amplifier receives the amplified signal from the echo signal amplified by the time gain amplifier (TGC). The gain controller controls the gain of the operational amplifier according to the strength of the amplified signal so that each of the adaptive conversion circuits provides an adaptive gain to adaptively adjust the gain of the amplified signal in each circuit. The analog-to-digital converter converts the signal output by the operational amplifier into a digital signal with adaptive gain. The analog-to-digital converter has different delays so that the multiplexer adaptive conversion circuits have different sampling time points.

2. The circuit structure according to claim 1, characterized in that: The echo signal is an analog signal acquired by an intravascular ultrasound catheter, which acquires ultrasound signals and converts the ultrasound signals into the echo signal.

3. The circuit structure according to claim 1, characterized in that: The adaptive conversion circuit further includes a filter disposed between the operational amplifier and the analog-to-digital converter, used to filter the signal output by the operational amplifier and generate a filtered signal.

4. The circuit structure according to claim 1, characterized in that: The time gain amplifier (TGC) amplifies the echo signal according to a preset time gain curve to obtain an amplified signal, and the time gain curve gradually increases over time.

5. The circuit structure according to claim 1, characterized in that: In the adaptive conversion circuit, the gain controller controls the gain of the operational amplifier according to the intensity gain curve and the intensity of the amplified signal, and the gain controller adjusts the gain of the amplified signal according to the gain corresponding to the intensity of the amplified signal in the intensity gain curve.

6. The circuit structure according to claim 1, characterized in that: The gain controller controls the gain of the operational amplifier based on a preset threshold and the strength of the amplified signal. If the amplified signal is greater than the threshold, the gain of the amplified signal is reduced; if the amplified signal is less than the threshold, the gain of the amplified signal is kept constant.

7. The circuit structure according to claim 1, characterized in that: The multi-channel adaptive conversion circuit includes three independent adaptive conversion circuits, which receive the amplified signal.

8. The circuit structure according to claim 7, characterized in that: It also includes a field-programmable array (FPGA), where the digital signal output by the multiplexer adaptive conversion circuit is input to the FPGA and fused to generate a target signal, which is then converted and displayed on the display screen as an image.

9. The circuit structure according to claim 8, characterized in that: The field-programmable array obtains the target signal based on a first digital signal, a second digital signal, and a third digital signal, wherein the target signal satisfies: F = ka × fa(t) + kb × fb(t) + kc × fc(t)……Equation (1) Wherein, F represents the target signal, fa(t) represents the first digital signal, ka represents the weight of the first digital signal, fb(t) represents the second digital signal, kb represents the weight of the second digital signal, fc(t) represents the third digital signal, and kc represents the weight of the third digital signal.

10. The circuit structure according to claim 1 or 2, characterized in that: The echo signal includes ultrasound signals reflected from the stent and ultrasound signals reflected from the blood vessel.

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