NL2020426B1 - Data collection system, in particular suitable for imaging of a distant object - Google Patents

Abstract

Data collection system, in particular suitable for imaging of a distant object (2), comprising a transmission line (7) with a proximal end (8) and a distal end (9), wherein at the distal end (9) at least one transducer (10) is provided 5 for transmitting an excitation signal and receiving a response signal, and amplifier means (12) to amplify the response sig— nal and to provide the amplified response signal at the distal end (9) to the transmission line (7), and wherein at the prox— imal end (8) of the transmission line (7) a data processor 10 (13) is provided for processing the amplified response signal received at the proximal end (8) of the transmission line (7), and wherein at the proximal end (8) of the transmission line (7) a power supply (14) is provided and a power source (15) for a transducer excitation signal, wherein the transmission 15 line (7) is embodied as a single line equipped to transmit both power from the power supply (14) and the transducer exci— tation signal from the proximal end (8) to the distal end (9), wherein multiple transducers (10) are provided at the distal end (9), and the proximal end (8) is provided with an address— 20 ing organ (17) for providing configuration data on the trans— mission line (7) to sequentially address and select one of the multiple transducers (10) to transmit the excitation signal and receive the response signal, and wherein the data proces— sor (13) is equipped to process and derive information from 25 the collection of response signals received back from the transducers (10).

Description

Patent center

Θ 2020426

Application number: 2020426

Application submitted: 13 February 2018

Int. Cl .:

A61B 8/00 (2018.01) B06B 1/02 (2019.01) G06F

13/00 (2019.01) G06F 13/40 (2019.01)

0 Application registered: 0 Patent holder (s): August 20, 2019 Delft University of Technology in Delft. 0 Request published: - 0 Inventor (s): Douwe Manuel van Willigen in Delft. 0 Patent granted: Michiel Antonius Petrus Pertijs in Delft. August 20, 2019 0 Patent issued: 0 Authorized representative: August 20, 2019 ir. J. van Breda et al. in Amsterdam.

54) Data collection system, in particular suitable for imaging or a distant object

Data collection system, particularly suitable for imaging of a distant object (2), including a transmission line (7) with a proximal end (8) and a distal end (9), being at the distal end (9) at least one transducer (10) is provided for transmitting an excitation signal and receiving a response signal, and amplifier means (12) to amplify the response signal and to provide the amplified response signal at the distal end (9) to the transmission line (7), and at the proximal end (8) or the transmission line (7) a data processor (13) is provided for processing the amplified response signal received at the proximal end (8) or the transmission line (7), and going at the proximal end (8) or the transmission line (7) a power supply (14) is provided and a power source (15) for a transducer excitation signal, the transmission line (7) is embodied as a single line equipped to transmit both power from the power supply (14) and the transducer excitation signal from the proximal end (8) to the distal end (9), multiple transducers (10) are provided at the distal end (9), and the proximal end (8) is provided with an addressing organ (17) for providing configuration data on the transmission line (7) to sequentially address and select one of the multiple transducers (10) to transmit the excitation signal and receive the response signal, and the data processor (13) is equipped to process and derive information from the collection of response signals received back from the transducers (10).

NL B1 2020426

This patent has been granted regardless of the attached result of the research into the state of the art and written opinion. The patent corresponds to the documents originally submitted.

Data collection system, particularly suitable for imaging or a distant object

The invention relates to a data collection system, in particular suitable for imaging of a distant object, including a transmission line with a proximal end and a distal end, with the distal end at least one transducer is provided for transmitting an excitation signal and receiving a response signal, and amplifier means to amplify the response signal and to provide the amplified response signal at the distal end to the transmission line, and at the proximal end of the transmission line a data processor is provided for processing the amplified response signal received at the proximal end of the transmission line, and at the proximal end of the transmission line a power supply is provided and a power source for a transducer excitation signal, the transmission line is embodied as a single line equipped to transmit both power from the power supply and the transducer excitation signal from the proximal end to the distal end.

Such a data collection system is known from WO00 / 61008, which discloses an ultrasound catheter with a rotatable transducer couples to the input or a preamplifier. Protection circuits at the input and output of the preamplifier protect the preamplifier from the transducer excitation signal. The preamplifier couples to the distal end of a transmission line. In an alternative embodiment, at least one switch responds to the presence of the transducer excitation signal by coupling the transducer excitation signal to the rotatable transducer and protecting the preamplifier from the transducer excitation signal. The said at least one switch responds to the absence of the transducer excitation signal by coupling a received signal produced by the rotatable transducer to the input of the preamplifier. The said at least one switch further responds to the absence of the transducer excitation signal by coupling the output of the preamplifier to the distal end of the transmission line.

WO00 / 61008 uses a single line to transfer power for the amplifier at the distal end and the transducer excitation signal for the single transducer at the distal end, however this system is unsuited for high-quality 3D real-time imaging with the least: possible amount: of motion artifacts ^ which would require an array of transducers at the: distal end, and multiple lines that would be required for sending signals to receiving signals from the respective transducers.

The article A Front-End ASIC with High-Voltage Transmit Switching and Receive: Digitization for ForwardLooking Intravascular Ultrasound by Mingliang Tan, Chao Chen, Zhao Chen, Uovana Janjic, Verya Daeichin, Zu-yao Chang, Emile 10 Noothout, Gijs ^ van Soest , Martin D. Verweij, Nico: de Jong, and Michiel AP Pertijs; presented at the Custom Integrated Circuits Conference CI GO 2017: Austin, TX, USA ISBN 27 8 --- 1 --- ^ 022-5121 --- 5: /17/$31.0002017IEEE presents · g front-end ASIC (: Application : Specific IC) for forward-looking intravas15 cular ultrasound (IVUS) imaging. The ASIC is intended to be mounted at the: tip of a catheter and can interface: a total of 80 piezo-electric transducer elements with an imaging system using only 4 cables. It is ^ capable: of switching high-voltage transmit pulses to 16 transmit elements, and capturing the: re20 suiting echo signals using 64 multiplexed receive elements .:

The ASIC digitizes the received signals locally.

It is an object of the invention to make possible that only a single: cable is used in the data collection system and that this data collection system still allows high quality real-time imaging substantially free of motion artifacts.

The: data collection system of the invention has ^ the: features of one or more of the: appended claims :.

In a first aspect of the invention the data collection system according to the preamble has the further features 30 that multiple transducers are provided at the distal end, and that the proximal end is provided with an addressing organ for providing configuration data on the transmission line to sequentially address and select: one of the multiple transducers at: the: distal end to transmit the excitation signal and re35 ceive the response: signal, and that the data processor at the proximal end is equipped to process and derive information from the collection of response signals received back from the transducers. In this arrangement four different signals are transmitted over the single transmission line, to: note: the:

power for the amplifier at the distal end, the configuration data, the excitation signal for the transducers and the response signals received back from the transducers. Although the invention makes possible to use but only a single transmission line, which has the tremendous advantage that the data collection system or the invention is capable of use in very narrow areas which do not leave much room for multiple transmission lines. This particularly but not exclusively applies to medical applications such as intravascular monitoring.

In a beneficial application of the invention the data processor is equipped to construct an image from the collection of response signals received back from the transducers.

In a preferred embodiment the addressing organ is arranged to superimpose the configuration data on the signal from the power supply traveling on the transmission line from the proximal end to the distal end.

Suitably the distal end is provided with a demodulator for retrieving the configuration data received at the distal end of the transmission line and to select the transducer to transmit the excitation signal to, and from which to receive back the response signal.

It is preferable that at the distal end protection circuitry is provided to secure the amplifier means against damage due to the transducer excitation signal.

Desirably further in the system of the invention the protection circuitry comprises switches with a transmit mode and a receive mode, the switches when in the transmit mode enable the transducer excitation signal to reach the transducers and block the transducer excitation signal from reaching the amplifier means , and that the switches when in the receive mode enable the response signals from the transducers to reach the amplifier means. However, it is also possible that the protection circuitry is embodied with a diodebridge circuit.

It is further beneficial that the protection circuitry at the distal end comprises a voltage limiter to protect the amplifier means. The voltage limiter provides further protection against high voltages from the excitation signal that drives the transducers, and which might without such protection circuitry damage the amplifier means.

To assist the switches in assuming a proper switching mode it is desirable that the protection circuitry at the distal end comprises a voltage level detector to establish whether the transmission line transmits a transducer excitation signal.

Suitably the voltage level detector drives the switches to transmit mode when it detects a voltage on the transmission line above a predetermined threshold value. Further it is desirable that the voltage level detector drives the switches to receive mode when it detects a voltage on the transmission line being below a predetermined threshold value for a predetermined time.

In a further preferred embodiment the amplifier means at the distal end is a current amplifier, at the proximal end a current sensor is provided that drives the data processor for processing the amplified response signal received at the proximal end of the transmission line. The application of a current amplifier has the notable advantage that the system is less sensitive for the capacitive load that the transmission line provides. Delivering performance in providing high quality real time imaging is improved in comparison with the alternative of voltage amplification. Instead of using a current amplifier it is also possible to apply frequency division multiplexing or to apply an analog-digital converter following the current amplifier.

Although the invention is not restricted thereto, the data collection system of the invention is particularly suited for intravascular imaging, the transducers are equipped to send and receive ultrasound from an intravascular object to be imaged.

The invention will be further elucidated with reference to the drawing of an exemplary embodiment of a data collection system for imaging according to the invention that is not limiting as to the appended claims.

In the drawing:

-figure 1 shows a schematic drawing or part of a data collection system of the invention when embodied as an intravascular ultrasound imaging system;

-figure 2 shows a further schematic drawing of signals transmitted over a transmission line of the data collection system of the invention;

-figure 3 shows a schematic diagram of building blocks forming part of the data collection system of the invention;

-figure 4 shows a more detailed circuit diagram representing the circuitry at a distal end of the transmission line; and

-figure 5 shows a more detailed circuit diagram representing the circuitry at a proximal end of the transmission line.

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

Turning first to figure 1 a blood vessel 1 is shown which suffers from stenosis 2 which is detected with the data processing system of the invention. For this purpose the data processing system is embodied as an intravascular ultrasound imaging system, only distant parts of which are shown in figure 1 as a catheter 3 with its corresponding guide wire 4, and at the distal end of the catheter 3 some electronics 5 for Sending and receiving ultrasound signals with an array of transducers 6. Normally the transducers are piezo-transducers, but this is not essential.

The electronics 5 are placed at the distal end of the catheter 3 and within the catheter a transmission line 7 is present to facilitate communication between a proximal end 8 of the data collection system, and the distal end 9 of the data collection system as together depicted in figure 3, with a transmission line 7 connecting both ends 8, 9.

Figure 3 shows for clarity a single transducer 10 at the distal end 8, although the shaded lines 11 represent that according to the invention multiple transducers are provided at the distal end 9. Each of the transducers 10 is provided for transmitting an excitation signal towards an object or in terest such as the stenosis 2 in figure 1, and receiving back a response signal which is monitored by the transducers 10. According to the invention the respective transducers 10 are activated sequentially one at a time to send excitation signals and receive back response signals. Further there are (usually singular) amplifier means 12 to amplify the response signals from the transducers 10. The amplifier means 12 provide the amplified response signals from the distal end to pass over the transmission line 7 back to the proximal end 8 of the data collection system.

At the proximal end 8 of the transmission line 8 a data processor 13 is provided for processing the amplified response signal that is received back at the proximal end 8 of the transmission line 7. The data processor 13 is equipped to construct an image from the collection or response signals received back from the multitude of transducers 10 at the distal end 9.

The respective signals that are required to communicate back and forth and to operate and control the electronics on the distal end 9 of the system of the invention all pass over the single transmission line 7. In connection therewith figure 3 shows that at the proximal end 8 of the transmission line 7 a power supply 14 is provided as well as a power source 15 for a transducer excitation signal Vtx that is required for feeding the transducers 10. The proximal end 8 is further provided with an addressing organ 17 for providing configuration data to pass over the transmission line 7 and that is used to sequentially address and select one of the multiple transducers 10 at a time to transmit the excitation signal Vtx and to receive back the response signal from the selected transducer

10. Since the excitation signal Vtx is a relatively high voltage signal or approximately 30 V, at the distal end 9 protection circuitry 16 is provided to secure the amplifier means 12 against damage which might otherwise be caused by the high voltage transducer excitation signal Vtx.

Figure 3 further depicts that the addressing organ 17 is arranged to superimpose the configuration data on the signal from the power supply 14 so as to jointly travel on the transmission line 7 from the proximal end 8 to the distal end

9. This joint signal is depicted in figure 2 as Vcable, being in this example a DC voltage power supply signal or 3 V on which the signal which is indicated (configuration) data is superimposed.

At the distal end 9 a demodulator 18 is provided for retrieving the (configuration) data received at the distal end 9 or the transmission line 7, which data is used to select the transducer 10 from the multitude of transducers which is to transmit the excitation signal and from which to receive the response signal back from.

According to another aspect protection circuitry 16 is applied in the data collection system of the invention that comprises switches with a transmit mode TX and a receive mode RX. The switches 16 are provided both at the proximal end 8 and at the distal end 9, and when in the transmit mode TX the switches 16 enable the transducer excitation signal Vtx to reach the transducers 10 and block the transducer excitation signal Vtx from reaching the amplifier means 12. In the receive mode RX the switches 16 enable the response signals from the transducers 10 to reach the amplifier means 12. Likewise the switches 16 also protect a sensor 19 which is provided at the proximal end 8 and that drives the data processor 13 for processing the amplified response signal received back at the proximal end 8 via the transmission line 7, and which signal originates from the amplifier 12. In this connection it is remarked that the amplifier 12 at the distal end 9 is preferably a current amplifier and that the sensor 19 is preferably a current sensor.

Figure 3 further shows the protection circuitry at the distal end 9 also preferably includes a voltage limiter 19 to protect the amplifier means 12 against the high voltage transducer excitation signal Vtx.

It shows further in Figure 3 that the protection circuitry at the distal end 9 comprises a voltage level detector 20 to establish whether the transmission line 7 transmits a high voltage transducer excitation signal Vtx. If that happens - which is shown in figure 2 as the peak voltage at the transmit instance - the voltage level detector 20 drives the switches 16 to transmit mode TX, that is when it detects a voltage on the transmission line 7 above a predetermined threshold value . On the other hand the voltage level detector 20 drives the switches 16 to receive mode RX when it detects that the voltage on the transmission line 7 is below a predetermined threshold value for a predetermined time. In that case the amplifier 12 is enabled to amplify the signal current requirements of the transducers 10 as symbolized in figure 2 with Icable and to transmit this amplified current back over the transmission line 7 to the proximal end 8. The current sensor 19 at the proximal end 8 receives these signals and supplies from the processor 13 which processes the sequential signals from the multiple transducers 10 at the distal end 9 into a real-time complete image of the object of interest 2 (figure 1).

In figure 4 and figure 5 respectively exemplary are shown of the electrical circuitry that can be used at the distal end 9 of the data collection system of the invention, as well as the electrical circuitry that can be used at the proximal end 8 of the data collection system of the invention.

FIG. 4 shows a block diagram of the circuitry at the distal end 9. Programmable switches Stx and Srx allow each element to be connected to the cable for TX, or to a low noise amplifier LNA for receiving mode RX. During receiving mode RX, a DC voltage or 3V on the cable powers the electronics at the distal end 9. To configure the switches, pulse-width modulated (PWM) data (500mVpp) is superimposed on the power supply. This is recovered by AC coupling, amplifying and thresholding, and then used to program a configuration shift register. A low dropout regulator (LDO) prevents the modulated supply from affecting the operation of the associated logic. After configuration, a high-voltage transmission mode TX signal with a maximum peak amplitude or 30V can be supplied to the cable, which will drive the elements selected for transmission mode TX to generate an acoustic pulse. This arrangement allows the pulse waveform to be defined on the system side. Transistors Ml and M3 clamp the high-voltage transmission mode TX signal to protect the low-voltage circuitry. A bias circuit (not shown) generates bias currents and Vclamp, which is stored on a ca pacitor during transmission mode TX, when a stable supply voltage is absent.

When the level detector senses that Vcable is below 6V for more than 200ns, the electronics at the distal end 9 switches back to the receiving mode RX by turning off the transmission mode TX switches and enabling the low noise amplifier LNA. The acoustic echoes received by the PZT element which is selected for receiving mode RX creates a small signal current that is amplified by the low noise amplifier LNA and returned to the proximal end 8 of the system by superimposing it on the supply current. The supply current is a constant offset, because the logic is quiet during this period, and can therefore easily be filtered out on the proximal system side. Compared to the alternative conventional solution or driving the cable with a signal voltage, which requires that the electronics at the distal end 9 drive the cable capacitance, this current mode signaling is more power efficient.

FIG. 5 shows a simplified diagram of the circuitry used on the proximal end 8 of the system to drive, configure and read out the electronics at the distal end 9 of the system. During receiving mode RX, a trans-impedance amplifier is used to supply the electronics at the distal end 9 with a fixed-supply voltage (Vsup) while converting the amplified signal current to a voltage VRX with a trans-impedance gain set by resistor R1. Resistor R2 is used to match the cable impedance, while capacitor C5 rejects the DC component associated with the supply current or the distal end 9 of the system. To configure the electronics at the distal end 9 of the system, PWM-encoded data Vdata is added to Vsup, causing the virtual ground of the shown operational amplifier to follow this signal, thus transmitting it over the coaxial cable to the distal end 9 or the system. During transmission mode TX, the high-voltage signal VTX generated by the system is AC-coupled to the cable.

Although the invention has been discussed in the foregoing with reference to an embodiment of the apparatus of the invention, the invention is not restricted to this particular embodiment which can be varied in many ways without departing from the invention. The discussed example is therefore not used to construct the appended claims strictly in accordance with therewith. On the contrary the embodiment is merely intended to explain the wording of the appended claims without intent to limit the claims to this 5 exemplary embodiment. The scope of protection of the invention shall therefore be constructed in accordance with the appended claims only, where possible ambiguity in the wording of the claims shall be resolved using this exemplary embodiment.

Claims (13)

CONCLUSIONS A data collection system, particularly suitable for imaging an isolated object (2), comprising a transmission line (7) with a proximal end (8) and a distal end (9), wherein at the distal end (9) at At least one transducer (10) is provided for transmitting an excitation signal and receiving a response signal, and amplifier means (12) for amplifying the response signal and providing the amplified response signal at the distal end (9) on the transmission line 10 (7), and wherein a data processor (13) is provided at the proximal end (8) of the transmission line (7) for processing the amplified response signal received at the proximal end (8) of the transmission line (7), and wherein at the proximal end (8) of the transmission line (7) a supply voltage (14) is provided and a voltage source (15) for a transducer excitation signal, wherein the transmission line (7) is provided as a single line designed for both power of the voltage source (14) and the transducer excitation signal from the proximal end (8) to the distal end (9), characterized in that a plurality of transducers (10) are provided for seen at the distal end (9), and the proximal end (8) is provided with an addressing means (17) for providing configuration data on the transmission line (7) for sequentially addressing and selecting one of the plurality of transducers (10) ) for transmitting the excitation signal and receiving the response signal, and wherein the data processor (13) is adapted to process and derive information from the set of response signals received back from the transducers 30 (10). A data collection system according to claim 1, characterized in that the data processor (13) is equipped to form an image of the collection of response signals received back from the transducers (10). 35 A data collection system according to claim 1 or 2, characterized in that the addressing device (17) is arranged for superimposing the configuration data on the signal of the supply voltage (14) traveling through the transmission line (7) of the proximal end ( 8) to the distal end (9). A data collection system according to any one of claims 1 - 3, characterized in that the distal end (9) is provided with a demodulator (18) for recovering the configuration data received at the distal end (9) of the transmission line (7) and selecting the transducer (10) which will send the excitation signal and from which the response signal will be received. A data collection system according to any one of claims 1 - 4, characterized in that a protection circuit (16, 19, 20) is provided at the distal end (9) for protecting the amplifier means (12) against damage caused by the transducer excitation signal. A data collection system according to claim 5, characterized in that the protection circuit (16, 19, 20) comprises switches (16) with a transmission mode and a reception mode, the switches (16) when in the transmission mode allowing the transducer excitation signal reaches the transducers (10) and blocks the transducer excitation signal in reaching the amplifier means (12), and in the receiving mode the switches (16) allow the response signals from the transducers (10) to reach the amplifier means (12). A data collection system according to claim 5 or 6, characterized in that the protection circuit (16, 19, 20) comprises a voltage limiter (19) at the distal end (9) for protecting the amplifier means (12). A data collection system according to any one of claims 5 - 7, characterized in that the protection circuit (16, 19, 20) includes a voltage level detector (20) at the distal end (9) for determining whether the transmission line (7) carries a transducer excitation signal. A data collection system according to claim 8, characterized in that the voltage level detector (20) sets the switches (16) in the transmission mode when it detects a voltage on the transmission line (7) above a predetermined threshold value. A data collection system according to claim 8 or 9, characterized in that the voltage level detector (20) sets the switches (16) in receiving mode when it detects a voltage on the transmission line (7) under a predetermined 5 threshold value for a predetermined time. A data collection system according to any one of claims 1 - 10, characterized in that the amplifier means (12) at the distal end (9) are formed by a current amplifier and that at the proximal end (8) there is provided a current A sensor (19) which controls the data processor (13) for processing the amplified response signal received at the proximal end (8) of the transmission line (7). A data collection system according to any one of claims 1 - 11, characterized in that the system has an ultrasonic imaging The system is particularly suitable for intravascular imaging, wherein the transducers (10) are adapted to transmit and receive ultrasound. 1/5