CN116763357A

CN116763357A - In-vivo navigation method of intravascular ultrasound probe

Info

Publication number: CN116763357A
Application number: CN202310664960.7A
Authority: CN
Inventors: 李玮; 张水兴; 田捷; 杨志云; 黄文慧
Original assignee: First Affiliated Hospital of Jinan University
Current assignee: First Affiliated Hospital of Jinan University
Priority date: 2022-06-20
Filing date: 2023-06-07
Publication date: 2023-09-19
Also published as: CN115089216A

Abstract

The application discloses an intravascular ultrasound (IVUS) probe in-vivo navigation method based on a Magnetic Particle Imaging (MPI) technology. The application utilizes MPI to the rapid imaging method of superparamagnetism material, uses MPI technology to navigate the intravascular IVUS probe with magnetic marker to realize intravascular detection without ionizing radiation injury. The device for realizing the method of the application consists of a modified IVUS subsystem, an MPI subsystem and a control subsystem. The end point of the IVUS probe or other parts which can be used for marking the position of the probe are coated with superparamagnetic coatings, and the real-time imaging of the probe marker is realized through an MPI subsystem, so that the accurate positioning and the intravascular navigation of the IVUS probe are realized. The control subsystem not only controls the imaging process of the MPI subsystem and the IVUS subsystem, but also processes the detection signals of the MPI subsystem and the IVUS subsystem in real time and is used for displaying the images of the MPI and the IVUS so as to intuitively and effectively navigate the IVUS probe. The method can realize IVUS blood vessel detection without ionizing radiation injury and has potential application value in pathological research of vascular diseases.

Description

In-vivo navigation method of intravascular ultrasound probe

Technical Field

The application belongs to the field of tissue imaging, and particularly relates to an intravascular ultrasound probe navigation method based on a magnetic particle imaging technology.

Background

Intravascular ultrasound (IVUS) is a technique in which an ultrasound transducer is placed within a blood vessel and ultrasound imaging is performed from within the blood vessel. IVUS imaging provides sufficient spatial resolution and imaging depth compared to other intravascular imaging modalities to accurately visualize coronary abnormalities. The arterial wall image provided by the IVUS image contains morphological and pathological features, and can be used for evaluating the area of a vascular lumen, the size of plaque, distribution, composition components and the like, so that the IVUS is widely used for cardiovascular disease pathological research and clinical diagnosis. In the pathology of cardiovascular disease, experimental animal models (such as rats, rabbits, pigs, etc.) need to be injected with iodine contrast agent, and then the position of the IVUS probe in the blood vessel is detected by using X-rays and the IVUS probe is navigated accordingly. However, the irradiation of X-rays causes injury to the laboratory operators and animals, and increases the incidence of cancers such as leukemia and thyroid malignant tumors.

MPI is a technique that uses the nonlinear response of a superparamagnetic substance (such as superparamagnetic iron oxide particles, SPIO) in a changing magnetic field to quantitatively detect the spatial distribution of the substance. The MPI has: the imaging speed is high, the imaging depth limit is avoided, the sensitivity is high, the ionizing radiation is avoided in the imaging process, and the like. The intravascular navigation of the IVUS probe is implemented based on the magnetic particle imaging technology, so that IVUS imaging without ionizing radiation can be realized, and the damage of the ionizing radiation to experimental operators and experimental animals can be avoided in the process of using the IVUS to conduct pathological research on vascular diseases.

Disclosure of Invention

The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

In order to complete the intravascular navigation of the IVUS probe without ionizing radiation injury, the application provides an IVUS probe in-vivo navigation method based on a Magnetic Particle Imaging (MPI) technology. Visualization of vascularity and lesion position by angiography of MPI, simultaneous detection and localization of in-vivo IVUS probe coated with superparamagnetic coating using MPI, visual navigation of the intravascular IVUS probe by MPI without ionizing radiation;

an object of the present application is to propose an IVUS probe in-vivo navigation system based on MPI technology;

the IVUS probe in-vivo navigation system based on the MPI technology comprises: IVUS subsystem, MPI subsystem and IVUS and MPI control subsystem.

The IVUS subsystem includes: the ultrasonic probe, the transmitting circuit, the receiving circuit and the catheter;

the ultrasonic probe comprises an ultrasonic transducer; the surface of the ultrasonic probe is coated with a superparamagnetic coating material for detecting and positioning the ultrasonic probe by an MPI subsystem;

in one example of the present application, the preparation method of the superparamagnetic coating material comprises: heating and stirring a polyvinyl alcohol (PVA) solution for more than 12 hours; after the solution was cooled to room temperature, dimethyl sulfoxide (dimethyl sulfoxide) and superparamagnetic iron oxide (SPIO) were added and stirred at room temperature; then, dialyzing the reacted mixed solution, and mixing the dialyzate with isopropanol; separating the iron-containing substance from the non-iron-containing impurities in the mixed solution using a magnet; finally, incorporating the separated iron-containing fraction into a varnish;

the transmitting circuit excites the ultrasonic probe to transmit ultrasonic waves to the vascular lumen and the vascular wall of the detected animal;

the receiving circuit controls the ultrasonic probe to receive the echo of the ultrasonic wave returned by the vascular lumen and the vascular wall, and an ultrasonic echo signal is obtained;

the catheter sends the ultrasonic probe into the blood vessel and reaches the target detection position;

the MPI subsystem includes: the device comprises a signal generator, a power amplifier, a resonance circuit, a band-pass filter, a first permanent magnet, a second permanent magnet, a first scanning coil, a second scanning coil, a third scanning coil, a fourth scanning coil, an excitation coil, a receiving coil, a signal amplifier and a low-pass filter; the first permanent magnet and the second permanent magnet are placed in the same pole in opposite directions, and a magnetic field-free point is generated at the center of the receiving coil and used for encoding the space position of the superparamagnetic substance; the signal generator generates 1 high-frequency sinusoidal alternating current and 2 low-frequency sinusoidal alternating currents, the sinusoidal alternating currents are amplified by the power amplifier respectively, and the high-frequency alternating currents enter the excitation coil through the resonance circuit and the band-pass filter in sequence to generate a high-frequency excitation magnetic field for exciting a nonlinear response signal of the superparamagnetic substance; the first scanning coil and the third scanning coil are connected in series, and are connected with low-frequency sinusoidal alternating current for scanning the non-magnetic field point in the horizontal direction; the second scanning coil and the fourth scanning coil are connected in series, and are connected with low-frequency sine alternating current for scanning the non-magnetic field point in the vertical direction; the receiving coil is arranged between the two permanent magnets and is used for detecting the nonlinear response of the superparamagnetic substance to the excitation magnetic field at the non-magnetic field point; the induced current generated by the nonlinear response is amplified by a signal amplifier, passes through a notch filter and a low-pass filter and is collected by a data collection card; the notch filter is used for reducing signal noise of the excitation frequency; the low-pass filter is used for reducing high-frequency signal noise;

the IVUS and MPI control subsystem includes: a terminal computer and a multichannel data acquisition card;

the multichannel data acquisition card comprises at least 2 receiving channels and 1 triggering output channel; the receiving channels are respectively used for receiving a receiving coil detection signal in the MPI subsystem and an ultrasonic probe detection signal in the IVUS subsystem; the trigger output channel is used for sending a trigger signal to the IVUS subsystem so as to realize the accurate control of the IVUS subsystem;

the terminal computer processes the ultrasonic echo signals to obtain and display a blood vessel ultrasonic image of the detected animal;

in one example of the present application, the signal generator in the MPI subsystem is implemented through 3 analog output channels integrated on the data acquisition card in the IVUS and MPI control subsystem for synchronous control;

in one example of the application, after the data acquisition card receives a regulation and control instruction from the terminal computer, 3 signal generators integrated on the data acquisition card respectively send out 1 high-frequency excitation current and 2 low-frequency scanning currents on the appointed frequency and amplitude; simultaneously, the trigger output channel sends a trigger signal to the IVUS subsystem; the IVUS subsystem starts to excite the probe and generate ultrasonic waves after receiving the trigger signal; 2 receiving channels synchronously start to respectively acquire detection signals of the MPI subsystem and the IVUS subsystem; storing the acquired signals into a computer cache to wait for image reconstruction;

the IVUS image is reconstructed into standard ultrasonic imaging signals and an image processing flow, and the IVUS image is not repeated here;

the MPI image reconstruction is a common X space or system matrix reconstruction method, and is not described herein;

another object of the present application is to provide an IVUS probe in-vivo navigation method based on the MPI technology, comprising the steps of:

step 1, placing a probe into a blood vessel through a catheter, and enabling the probe to be in an imaging view of an MPI subsystem;

step 2, starting to perform real-time imaging of the IVUS subsystem; moreover, the detection of superparamagnetic coating signals of the intravascular IVUS probe is carried out by MPI imaging technology;

step 3: performing three-dimensional image reconstruction by using the MPI signal obtained in the step 2, and simultaneously obtaining a blood vessel image and the position of the IVUS probe;

step 4: based on the blood vessel image obtained in the step 3 and the instant space position of the IVUS probe, navigating the IVUS probe to a blood vessel target detection position;

in one example of the application, the angiography method is: injecting the diluted SPIO solution into a blood vessel, exciting SPIO particles by using a high-frequency sinusoidal alternating magnetic field in an MPI subsystem, receiving a nonlinear response signal of the SPIO in the alternating magnetic field by a receiving coil of the MPI subsystem, and realizing the space positioning of the SPIO by space scanning of the MPI subsystem; after the image of the MPI subsystem is reconstructed, the SPIO in the blood vessel is tracked by the MPI image, and the flow track of the SPIO solution in the blood vessel is the blood vessel image;

the application has the advantages that: the method can realize in-vivo navigation of the IVUS probe under the condition of no ionizing radiation (no X-ray), and avoids the damage of the ionizing radiation to experimental operators and experimental animals in the use process of the IVUS.

Drawings

FIG. 1 is a schematic diagram of one implementation of an IVUS probe in-vivo navigation system based on MPI technology;

FIG. 2 is a block diagram of the IVUS probe in-vivo navigation system based on MPI technology of the present application;

fig. 3 is a block diagram of the control subsystem of the IVUS probe on-body navigation system based on the MPI technique and the MPI signal generator integrated in the subsystem of the present application.

Detailed Description

The application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. Based on the embodiments of the application described in the present application, all other embodiments that a skilled person would have without inventive effort shall fall within the scope of the application. It should be noted that, for convenience of description, only the portions related to the present application are shown in the drawings.

As shown in fig. 1 and 2, the IVUS probe on-body navigation system based on the MPI technique of the present embodiment includes: an IVUS subsystem, an MPI subsystem and a control subsystem;

as shown in fig. 1, the IVUS subsystem includes: an ultrasound probe 105, transmit circuitry 101, receive circuitry 103, and catheter 104. In addition, a transmit/receive selection switch 102 may be included.

The ultrasound probe 105 is any probe for intravascular ultrasound detection. Wherein the sonic head portion of ultrasonic probe 105 may be an array of a plurality of ultrasonic transducers, such as a circular array about the axis of the catheter; the ultrasonic transducer is used for transmitting ultrasonic wave beams according to the excitation electric signals or converting received ultrasonic echo waves into electric signals so as to realize the generation of ultrasonic detection waves and the receiving of echo signals; the surface of the end point position of the ultrasonic probe 105 is coated with a superparamagnetic coating material for detecting and positioning the ultrasonic probe by the MPI subsystem;

the catheter 104 is used for sending the ultrasonic probe 105 into the blood vessel and connecting the ultrasonic probe 105 with the transmission/reception selection switch 102;

the transmit circuit 101 is configured to generate a transmit sequence for controlling the single or multiple ultrasound transducers to transmit ultrasound waves to tissue in accordance with the control of the control subsystem.

The receiving circuit 103 is configured to receive electrical signals of the ultrasonic echo returned from the probe 105 and to send the ultrasonic echo signals into the control subsystem.

As shown in fig. 1, the MPI subsystem includes: a first scanning coil 106, a first permanent magnet 107, a second scanning coil 108, an excitation coil 109, a third scanning coil 110, a fourth scanning coil 111, a second permanent magnet 112, and a receiving coil 113; wherein the first permanent magnet 107 and the second permanent magnet 112 are placed in the same pole in opposite directions, and a magnetic field-free point is generated at the center of the receiving coil 113 for encoding the spatial position of the superparamagnetic substance; the first scanning coil 106 and the third scanning coil 110 are connected in series, and are connected with low-frequency sine alternating current for scanning the non-magnetic field point in the horizontal direction; the second scanning coil 108 and the fourth scanning coil 111 are connected in series, and are connected with low-frequency sine alternating current for scanning the non-magnetic field point in the vertical direction; the exciting coil 109 is connected with high-frequency sine alternating current and is used for exciting nonlinear response signals of the superparamagnetic substance; the receiving coil 113 is used for receiving a response signal of the superparamagnetic substance.

As shown in fig. 3, the control subsystem includes: a terminal computer PC and a multichannel data acquisition card DAQ; the terminal computer is connected with the multichannel data acquisition card DAQ; the multichannel data acquisition card DAQ comprises a first analog receiving channel IO0, a second analog receiving channel IO1, a trigger output channel Tri and first to third analog output channels AO 0-IO 2; the trigger output channel Tri is connected to the trigger end of the IVUS transmitting circuit and used for regulating and controlling the synchronous operation of the IVUS subsystem and the MPI subsystem; the first analog receiving channel IO0 and the second analog receiving channel IO1 are respectively connected with the receiving coil 113 of the MPI subsystem and the receiving circuit 103 of the IVUS subsystem and are respectively used for receiving the MPI receiving coil signal and the IVUS probe detection signal; the first to third analog output channels AO0 to IO2 are used as signal generators of an MPI subsystem; the first to third analog output channels AO0 to IO2 are respectively connected to power amplifiers of the MPI subsystem and are respectively used for generating sinusoidal alternating currents of an MPI excitation coil, an MPI Y-axis scanning coil and an MPI Z-axis scanning coil; after receiving a regulation and control instruction from a terminal computer PC, a multichannel data acquisition card DAQ respectively sends out 1 high-frequency excitation current and 2 low-frequency scanning currents on specified frequencies and amplitudes of first to third analog output channels AO 0-IO 2; the first analog receiving channel IO0 and the second analog receiving channel IO1 synchronously start to respectively acquire signals of the MPI subsystem and the IVUS subsystem; the collected signals are stored in a terminal computer PC buffer memory to wait for image reconstruction.

The IVUS probe in-vivo navigation based on the MPI technology of the present embodiment includes the following steps:

(1) Placing the probe 105 into the blood vessel through the catheter 104 and leaving the probe in the imaging field of view of the MPI subsystem; simultaneously, starting to perform real-time imaging of the IVUS subsystem;

(2) Injecting the diluted SPIO solution into a blood vessel, simultaneously exciting the SPIO particles and the superparamagnetic coating of the intravascular probe 105 by using a high-frequency sinusoidal alternating magnetic field in the MPI subsystem, and simultaneously receiving nonlinear response signals of the SPIO and the superparamagnetic coating of the probe 105 in the alternating magnetic field through a receiving coil 113; the low-frequency sine alternating current is connected into the first scanning coil 106 and the third scanning coil 110 to generate an alternating magnetic field in the horizontal direction, so that scanning without magnetic field points in the horizontal direction is realized; the low-frequency sine alternating current is connected into the second scanning coil 108 and the fourth scanning coil 111 to generate an alternating magnetic field in the vertical direction, so that scanning without magnetic field points in the vertical direction is realized; the magnetic fields generated by the exciting coil 109, the first scanning coil 106, the second scanning coil 108, the third scanning coil 110 and the fourth scanning coil 111 in the MPI subsystem are combined with each other to realize the spatial scanning without magnetic field points and the excitation of nonlinear response signals of superparamagnetic substances;

(3): using the response signal measured in (2) by the receiving coil 113, realizing three-dimensional image reconstruction of the MPI subsystem by a standard MPI system matrix image reconstruction method, thereby simultaneously obtaining a blood vessel image and the position of the probe 105;

(4): based on the vessel image obtained in step (3) and the instantaneous spatial position of the probe 105, the IVUS probe 105 is navigated to a vessel target detection position.

Claims

1. An IVUS probe on-body navigation system based on the MPI technology, which is characterized in that the IVUS probe on-body navigation system based on the MPI technology comprises: an IVUS subsystem, an MPI subsystem and an IVUS and MPI control subsystem;

and the terminal computer processes the ultrasonic echo signals to obtain and display a blood vessel ultrasonic image of the detected animal.

2. The imaging method of claim 1, wherein: the ultrasonic probe comprises an ultrasonic transducer; the surface of the ultrasonic probe is coated with a superparamagnetism coating material for detecting and positioning the ultrasonic probe by the MPI subsystem.

3. The imaging method according to claim 1, characterized in that the imaging method comprises the steps of:

step 4: and (3) navigating the IVUS probe to a vascular target detection position based on the vascular image obtained in the step (3) and the instant space position of the IVUS probe.