Wireless gating system for magnetic resonance imaging

Abstract

For example, a magnetic resonance imaging (MRI) system uses a magnetic field and radio frequency waves to generate anatomical images of a biological organism, such as a human body. Example MRI systems may implement prospective gating techniques, such as electrocardiographic gating and / or respiratory gating, to provide some examples to improve image quality of anatomical images. Prospective gating techniques utilize one or more physiological events of a biological organism to trigger an example MRI system to image the biological organism at a particular time to improve image quality of anatomical images, compensate for interference that may be introduced by magnetic fields and / or radio frequency waves.

Description

Background Art

[0001] Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to produce anatomical images of a biological organism. MRI is widely used in hospitals and clinics for medical diagnosis, staging, and tracking of various diseases. Medical personnel can use MRI to examine the brain, spinal cord, bones, joints, heart, blood vessels, and other internal organs of a biological organism. For example, medical personnel can use MRI to evaluate the structure of the heart and aorta to detect aneurysms or tears. As another example, medical personnel can use MRI to evaluate glands and organs in the abdomen of a biological organism, and can provide accurate information about the structure of the joints, soft tissues, and bones of a biological organism. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The accompanying drawings are incorporated herein and constitute a part of the specification, and are used to illustrate the present disclosure and, together with the description, further explain the principles of the present disclosure and enable those skilled in the relevant art to make and use the present disclosure. Various aspects of the present disclosure can be best understood by reading the following detailed description in conjunction with the accompanying drawings. It is worth noting that, in accordance with standard industry practice, the features are not drawn to scale. In fact, the size of the features may be arbitrarily increased or reduced for clarity of discussion. In the drawings:

[0003] Figure 1 graphically illustrates a simplified block diagram of an example magnetic resonance imaging (MRI) system according to some example embodiments of the present disclosure;

[0004] Figure 2 graphically illustrates various signals within an example MRI imaging system according to some example embodiments of the present disclosure;

[0005] Figure 3 graphically illustrates a block diagram of an example gated transmitter that may be implemented within an example MRI imaging system according to some example embodiments of the present disclosure;

[0006] Figure 4 graphically illustrates a block diagram of an example gradient shift filter that may be implemented within an example gated transmitter in accordance with some example embodiments of the present disclosure;

[0007] Figure 5 graphically illustrates a block diagram of an example gated receiver that may be implemented within an example MRI imaging system according to some example embodiments of the present disclosure; and

[0008] Figure 6 A simplified block diagram of a computer system suitable for use with the embodiments described herein is graphically shown according to some example embodiments of the present disclosure.

[0009] In the accompanying drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears. DETAILED DESCRIPTION

[0010] The following disclosure provides many different embodiments or examples for implementing different features of the subject matter provided. Specific examples of various components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be limiting. For example, the form of the first feature above the second feature in the following description may include an embodiment in which the first feature and the second feature are formed in direct contact, and may also include an embodiment in which additional features may be formed between the first and second features so that the first feature and the second feature may not be in direct contact. In addition, the present disclosure may repeat reference numbers and / or letters in the examples. This repetition itself does not determine the relationship between the embodiments and / or configurations discussed.

[0011] Overview

[0012] An example magnetic resonance imaging (MRI) system utilizes a magnetic field and radio frequency waves to generate anatomical images of a biological organism, such as (as an example) a human body. Due to one or more physiological events of the biological organism (e.g., the heartbeat and / or breathing of the biological organism), the image quality (e.g., contrast and spatial resolution) of the anatomical images generated by the example MRI system may be less than ideal. As will be described in further detail below, the example MRI system can implement prospective gating techniques, such as electrocardiographic gating and / or respiratory gating as examples, to improve the image quality of the anatomical images. The prospective gating technique utilizes one or more physiological events of the biological organism to trigger the example MRI system to image the biological organism at a specific time to improve the image quality of the anatomical images. However, the magnetic field and / or radio frequency waves may interfere with the prospective gating technique. As will be described in further detail below, the example MRI system compensates for the interference introduced by the magnetic field and / or radio frequency waves.

[0013] Example Magnetic Resonance Imaging (MRI) System

[0014] Figure 1 A simplified block diagram of an example magnetic resonance imaging (MRI) system is graphically shown in accordance with some example embodiments of the present disclosure. Figure 1 In the illustrated example embodiment, imaging system 100 represents a magnetic resonance imaging (MRI) system that uses magnetic fields and radio frequency waves to generate anatomical images of a biological organism, such as a human body, for example. Figure 1The imaging system 100 is described as a magnetic resonance imaging (MRI) system, but those skilled in the relevant art will recognize that the teachings herein are equally applicable to other types of imaging systems, such as computed tomography (CT) imaging systems, computed axial tomography (CAT) imaging systems, and / or positron emission tomography (PET) imaging systems (provided as some examples), without departing from the spirit and scope of the present disclosure. Figure 1 As shown, the imaging system 100 includes a patient transport table 102, an imaging machine 104, an MRI computer control system 106, a management workstation 108, a gating signal transmitter 110, and a gating signal receiver 112. Figure 1 The imager 104 shown in the figure is a standard imager having a long cylinder with a narrow tube in the center, also referred to as a bore, but those skilled in the relevant art will recognize that the teachings herein are equally applicable to other types of imagers, such as short-bore imagers, open-type imagers having a bore with an opening, and / or wide-bore imagers (provided as some examples) without departing from the spirit and scope of the present disclosure.

[0015] The patient transport table 102 positions the patient 116 on the patient transport table 102 into the imaging machine 104. In some embodiments, the patient transport table 102 may be adjustable in three dimensions, such as height, pitch, roll, and / or yaw, to slide the patient into the imaging machine 104. Figure 1 As shown, a patient 116 is positioned on a patient transport table 102, which can be adjusted to position (eg, slide) the patient 116 into the imaging machine 104 for imaging.

[0016] The imaging machine 104 uses a combination of magnetic fields and radio frequency waves to perform magnetic resonance imaging (MRI) on the patient 116. Figure 1 In the illustrated example embodiment, the imaging machine 104 generates a strong, stable main magnetic field, for example, between about 0.5 Tesla (T) and about 3.0 T. In some embodiments, once the patient 116 is positioned in the imaging machine 104, the main magnetic field surrounds the patient 116. In these embodiments, the main magnetic field can cause subatomic particles (e.g., protons) within the tissue of the patient 116 to align with the main magnetic field. In these embodiments, protons are typically protons of hydrogen atoms and are naturally abundant in biological organisms, particularly in water and fat cells within these organisms.

[0017] The imaging machine 104 may generate one or more changing secondary magnetic fields (e.g., gradient magnetic field pulses) that slightly distort the main magnetic field to allow imaging of different spatial locations (e.g., slices) of the patient 116. These gradient magnetic field pulses may be directed toward a specific spatial location or slice of the patient 116 to image the specific spatial location. In some embodiments, the gradient magnetic field pulses may cause a frequency change at a specific spatial location or slice of the patient 116 so that the specific spatial location may be excited by radio frequency waves.

[0018] The imaging machine 104 can generate radio frequency waves, such as radio frequency pulses, which are directed toward the patient 116 to image a specific spatial location of the patient 116. In some embodiments, subatomic particles within the tissue of the patient 116 within the specific spatial location absorb the radio frequency pulses. In these embodiments, the subatomic particles absorb the energy of the radio frequency pulses, causing the particles to rotate away from the main magnetic field. In these embodiments, when the frequency of the radio frequency pulses matches the precession frequency of the rotation of the subatomic particles, the subatomic particles absorb and rotate away from the main magnetic field. In these embodiments, the imaging machine 104 can deactivate the radio frequency pulses to allow the subatomic particles to slowly return to their alignment within the main magnetic field, which releases the energy absorbed from the radio frequency pulses. In general, the amount of energy released by the subatomic particles is related to the chemical properties of the tissue of the patient 116. In some embodiments, the imaging machine 104 can detect the amount of energy released, for example, using a coil placed around the patient 116 ( Figure 1 In these embodiments, the imaging machine 104 may then convert the detected released energy into electrical signals to provide the control system 106 with image data signals indicative of the tissue composition of the patient 116 within a particular spatial location.

[0019] The control system 106 may include one or more computing devices, such as one or more desktop computers, one or more rack-mount computers, one or more computer hardware servers, and / or any other computing device having one or more processors as will be appreciated by those skilled in the relevant art(s) without departing from the spirit and scope of the present disclosure. Figure 1 1 , but the control system 106 may include or be connected to other hardware components for operating the imaging machine 104, such as one or more waveform generators, one or more amplifiers, one or more RF transmitters, one or more RF receivers, one or more digital-to-analog converters (DACs), one or more analog-to-digital converters (ADCs), one or more mixers, one or more power supplies, one or more water pumps, one or more supercooled fluid (such as liquid helium or liquid nitrogen as some examples) pumps, etc., and / or one or more supercooled fluid storage tanks (as some examples). These other hardware components are well known to those skilled in the relevant art and are therefore not discussed in detail.

[0020] In some embodiments, the control system 106 can configure the gradient magnetic field pulses and / or radio frequency pulses applied by the imaging machine 104 to image the patient 116 to obtain image data signals. For example, the control system 106 can configure the gradient magnetic field pulses to excite specific spatial locations (e.g., slices) of the patient 116 to be imaged, and / or can configure various radio frequency pulses to image these specific spatial locations. In some embodiments, the control system 106 can control one or more waveform generators that generate gradient magnetic field pulses and / or radio frequency pulses and / or one or more amplifiers that enhance the gradient magnetic field pulses and / or radio frequency pulses. In these embodiments, the one or more waveform generators and / or one or more amplifiers can be implemented as independent or discrete devices, and / or can be introduced into or coupled to the control system 106.

[0021] In some embodiments, the control system 106 may analyze the image data signals provided by the imaging machine 104 to generate an anatomical image of the patient 116. In these embodiments, the anatomical image of the patient 116 graphically illustrates the tissue composition of the patient 116 within a spatial location. In some embodiments, the control system 106 may transform the image data signals using a mathematical transform (e.g., a Fourier transform) to mathematically transform the image data signals into an anatomical image of the patient 116. In these embodiments, the Fourier transform allows the image data signals to be decomposed into a combination of sinusoidal waves of different frequencies, phases, and amplitudes, which can be used to generate an anatomical image of the patient 116, as will be appreciated by those skilled in the relevant art without departing from the spirit and scope of the present disclosure.

[0022] The management workstation 108 may display one or more of the anatomical images of the patient 116 generated by the control system 106. In some embodiments, the management workstation 108 may further process one or more of the anatomical images of the patient 116 to change their features, such as windowing and / or magnification, to reformat one or more of the anatomical images of the patient 116, or to display a particular view of the patient 116 from the anatomical images of the patient 116, as some examples. In some embodiments, the management workstation 108 may be disposed in a dedicated location within the imaging system 100 that is electrically and / or magnetically isolated from the imaging machine 104 and / or the control system 106.

[0023] exist Figure 1 In the example embodiment shown, the image quality (e.g., contrast and spatial resolution) of the anatomical images generated by the control system 106 may be less than ideal due to one or more physiological events of the patient 116 (e.g., the heartbeat and / or breathing of the patient 116). Figure 1In the illustrated example embodiment, the control system 106 may implement one or more gating techniques, such as prospective gating techniques (e.g., ECG gating and / or respiratory gating) and / or retrospective gating techniques, to improve the image quality of the anatomical image. The one or more gating techniques utilize one or more physiological events of the patient 116 to trigger the imaging machine 104 to image the patient 116 at a specific time to improve the image quality of the anatomical image, such as improving the temporal resolution of the anatomical image and / or minimizing imaging artifacts caused by one or more physiological events of the patient 116. For example, when implementing ECG gating, the control system 106 may trigger the imaging machine 104 to image the patient 116 during a specific portion of the cardiac cycle (e.g., diastole when the ventricles of the heart are passively filled). As another example, the control system 106 may predict the phase of the respiratory cycle when the patient 116 is breathing freely when implementing respiratory gating, which may improve the contrast and spatial resolution of the anatomical image.

[0024] like Figure 1 As shown, one or more sensors 118 may be placed on the patient 116 to provide one or more physiological event signals that can be used to measure one or more physiological events of the patient 116. In some embodiments, the one or more sensors 118 may include one or more cardiac activity electrodes placed on the chest, arms, and / or legs of the patient 116 to provide one or more electrocardiogram (ECG) signals, their characteristic P waves, Q waves, R waves, S waves, T waves, and U waves, and / or associated QRS complexes combined with any other signal deflections represented by a given waveform. In these embodiments, the control system 106 may measure the electrical activity of the heart of the patient 116 based on the one or more ECG signals, as will be recognized by those skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In some embodiments, the one or more sensors 118 may include a pulse oximeter placed on a finger of the patient 116 to provide a photoplethysmogram (PPG) signal. In these embodiments, the control system 106 may measure the heart pulse rate of the patient 116 based on the PPG signal, as will be recognized by those skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In some embodiments, one or more sensors 118 may include a respiration sensor, such as a chest strap, bellows, or cushion, as some examples, that is placed around the abdomen and / or chest of patient 116 to provide a respiration (RESP) signal. In these embodiments, control system 106 may measure the respiratory expansion of the abdomen and / or chest of patient 116 based on the RESP signal, as will be appreciated by those skilled in the relevant art(s), without departing from the spirit and scope of the present disclosure. Figure 1In the example embodiment shown, as will be appreciated by those skilled in the relevant art(s), the control system 106 may utilize one or more ECG signals, PPG signals, and / or RESP signals to trigger the imaging machine 104 according to various prospective gating techniques without departing from the spirit and scope of the present disclosure.

[0025] One or more physiological event signals may be transmitted to the gated signal transmitter 110 using one or more leads 120. In some embodiments, one or more leads 120 may be implemented as simple conductors of tin, copper, and / or silver (as some examples), or may be implemented as more complex conductors shielded using polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), thermoplastic elastomer (TPE), thermoplastic rubber (TPR), thermoplastic polyurethane (TPU), fluorinated ethylene propylene (FEP), and / or ethylene tetrafluoroethylene (ETFE) (as some examples). Figure 1 In the illustrated example embodiments, gradient magnetic field pulses and / or radio frequency pulses used by the imaging machine 104 may interfere with one or more physiological event signals. In some embodiments, the gradient magnetic field pulses and / or radio frequency pulses may introduce gradient pulse interference and / or signal offsets (e.g., common mode offsets) into one or more physiological event signals. In these embodiments, the gradient magnetic field pulses may be coupled to one or more leads 120 when the one or more physiological event signals are transmitted through one or more leads 120. In these embodiments, the radio frequency pulses may be demodulated into common mode interference, which may affect, for example, power rails and / or high impedance circuit nodes of the imaging system 100, thereby introducing unwanted noise (e.g., amplitude modulation (AM) noise, as an example) into one or more physiological event signals.

[0026] exist Figure 1In the exemplary embodiment shown, the gated signal transmitter 110 compensates for interference introduced into one or more physiological event signals by gradient magnetic field pulses and / or radio frequency pulses. In some embodiments, the gated signal transmitter 110 may process one or more physiological event signals to reduce interference introduced into one or more physiological event signals by gradient magnetic field pulses and / or radio frequency pulses, such as (as some examples) gradient pulse interference and / or signal offset. In some embodiments, as will be described in further detail below, the gated signal transmitter 110 may compensate for gradient pulse interference. In these embodiments, the gated signal transmitter 110 may use nonlinear separation techniques, such as median filters, mean filters, wavelet or Lancre filters, phase detectors, mixers, oscillators, modulators, or any combination thereof (as a few non-limiting examples), to reduce gradient pulse interference. In some embodiments, as will be described in further detail below, the gated signal transmitter 110 may compensate for signal offset. In these embodiments, the gated signal transmitter 110 may evaluate an interference cost function (described in further detail below) to reduce signal offset. As Figure 1 As shown, the gated signal transmitter 110 provides the one or more physiological event signals to the gated signal receiver 112 for transmission to the control system 106. In some embodiments, the gated signal receiver 112 can be implemented as an independent or separate device, such as Figure 1 As shown, and / or may be incorporated into or coupled to control system 106. Example embodiments of gating signal transmitter 110 and gating signal receiver 112 are described in further detail below.

[0027] Example Physiological Event Signals within an Example MRI Imaging System

[0028] Figure 2 Various signals within an example MRI imaging system according to some example embodiments of the present disclosure are graphically illustrated. As described above, cardiac activity electrodes may be placed on a patient (e.g., Figure 1 The chest, arms and / or legs of the patient 116) in order to provide Figure 2 The electrocardiogram (ECG) signal 200 is shown. Figure 2 As shown, ECG signal 200 represents a clean ECG signal that is not interfered by gradient magnetic field pulses and / or radio frequency pulses used to image a patient. Figure 2 In the exemplary embodiment shown, interference from gradient magnetic field pulses and / or radio frequency pulses is graphically illustrated as an undesired noise signal 210. Figure 2As shown, the undesired noise signal 210 may include a slow gradient interference pulse 212 caused by the switching of the gradient magnetic field pulse and a fast gradient interference pulse 214 caused by the switching of the radio frequency pulse. In some embodiments, the slow gradient interference pulse 212 and / or the fast gradient interference pulse 214 may be generated in the same manner as described above. Figure 1 Gradient pulse interference and / or signal offsets are introduced into the ECG signal 200 in a substantially similar manner as described in to provide a noisy ECG signal 220. In some embodiments, the noisy ECG signal 220 may include rapid pulses superimposed on the ECG signal 200, such as having a duration between about 0.1 milliseconds (ms) and about four (4) ms, and / or long signal offsets, such as between about fifty (50) milliseconds (ms) and about two hundred (200) ms.

[0029] Example Gated Transmitter That May Be Implemented Within an Example MRI Imaging System

[0030] Figure 3 A block diagram of an example gated transmitter that may be implemented within an example MRI imaging system according to some example embodiments of the present disclosure is graphically illustrated. Figure 1 The gradient magnetic field pulses and / or radio frequency pulses used by the imaging device 104 in the embodiment may be in the same manner as described above. Figure 1 and Figure 2 The gated signal transmitter 300 can compensate for interference introduced into the one or more physiological event signals by the gradient magnetic field pulses and / or the radio frequency pulses in a manner substantially similar to that described in the foregoing. As will be described in further detail below, the gated signal transmitter 300 can compensate for interference introduced into the one or more physiological event signals by the gradient magnetic field pulses and / or the radio frequency pulses. Figure 3 As shown, the gated signal transmitter 300 may include an analog processing circuit device 302, an analog-to-digital (ADC) converter 304, a digital processing circuit device 306, and / or a communication transmitter 308. In some embodiments, the gated signal transmitter 300 may represent the above Figure 1 An example embodiment of the gating signal transmitter 110 described in .

[0031] The analog processing circuit device 302 may process the noisy physiological event signal 350 in the analog signal domain, for example, by amplification and / or signal conditioning, to provide a processed physiological event signal to the ADC 304. Figure 3 As shown, the noisy physiological event signal 350 may include an electrocardiogram (ECG) signal 350.1, a photoplethysmogram (PPG) signal 350.2, and a respiration (RESP) signal 350.3. In some embodiments, the physiological event signal 350 may be detected by combining one or more sensors (e.g., Figure 1 One or more sensors 118 as described above can be used with Figure 1Placed into the patient in a substantially similar manner as described in Figure 1 In these embodiments, one or more leads (e.g., as described above) are used to generate ECG signals 350.1, PPG signals 350.2, and / or RESP signals 350.3. Figure 1 One or more leads 120 described in the foregoing may be connected between one or more sensors and the analog processing circuit device 302 to transmit the ECG signal 350.1, the PPG signal 350.2 and / or the RESP signal 350.3 to the analog processing circuit device 302. In some embodiments, the ECG signal 350.1 may be characterized as a relatively fast electrical signal, the PPG signal 350.2 may be characterized as a relatively slow electrical signal, and the RESP signal 350.3 may be characterized as an optical signal. In these embodiments, it may be assumed that the PPG signal 350.2 and / or the RESP signal 350.3 are not affected by the interference of the gradient magnetic field pulse and / or the radio frequency pulse compared to the ECG signal 350.1. In this way, the gated signal transmitter 300 compensates for the interference introduced into the ECG signal 350.1 from the gradient magnetic field pulse and / or the radio frequency pulse, as will be described in further detail below. However, those skilled in the relevant art will recognize that the teachings described herein for compensating for interference introduced into the ECG signal 350.1 by the gradient magnetic field pulses and / or the radio frequency pulses are equally applicable to compensating for interference introduced into the PPG signal 350.2 and / or the RESP signal 350.3 from the gradient magnetic field pulses and / or the radio frequency pulses without departing from the spirit and scope of the present disclosure. In some embodiments, the ECG signal 350.1, the PPG signal 350.2 and / or the RESP signal 350.3 may represent one or more differential signals.

[0032] The analog processing circuit arrangement 302 includes an ECG analog front end (AFE) 310.1, a PPG AFE 310.2, and a RESP AFE 310.3 for receiving an ECG signal 350.1, a PPG signal 350.2, and a RESP signal 350.3, respectively. Figure 3In the example embodiment shown, the ECG AFE 310.1, the PPG AFE 310.2, and the RESP AFE 310.3 may process the ECG signal 350.1, the PPG signal 350.2, and the RESP signal 350.3, respectively, in the analog signal domain, such as by amplification and / or signal conditioning. In some embodiments, the ECG AFE 310.1, the PPG AFE 310.2, and / or the RESP AFE 310.3 may include a signal converter, such as an optoelectronic converter as an example, to convert the ECG signal 350.1, the PPG signal 350.2, and / or the RESP signal 350.3 into an electrical signal. In some embodiments, the ECG AFE 310.1, the PPG AFE 310.2, and the RESP AFE 310.3 may include various amplifiers, such as (as some examples) operational amplifiers and / or differential amplifiers, to amplify the ECG signal 350.1, the PPG signal 350.2, and the RESP signal 350.3, respectively. In some embodiments, the ECG AFE 310.1, PPG AFE 310.2, and RESP AFE 310.3 may include various filters, such as (as some examples) low-pass filters, band-pass filters, high-pass filters, and / or anti-aliasing filters, to condition the ECG signal 350.1, the PPG signal 350.2, and the RESP signal 350.3, respectively.

[0033] In some embodiments, the ECG AFE 310.1, the PPG AFE 310.2, and / or the RESP AFE 310.3 may process the ECG signal 350.1, the PPG signal 350.2, and the RESP signal 350.3, respectively, in different ways from one another in the analog signal domain. For example, the ECG AFE 310.1 may include an anti-aliasing filter having a bandwidth of approximately one (1) kilohertz (kHz), coupled to an amplifier having a gain of one, also referred to as a buffer amplifier. The anti-aliasing filter having a bandwidth of one (1) kHz is sufficient to capture interference from gradient magnetic field pulses and / or radio frequency pulses introduced into the ECG signal 350.1. As another example, the PPG AFE 310.2 may include a first bandpass filter having a bandwidth between approximately 500 Hertz (Hz) and approximately 10 kHz, coupled to an amplifier having a gain of approximately 1000, which is coupled to a third order low pass filter having a bandwidth of approximately twelve (12) Hz. As yet another example, the RESPAFE 310.3 may include a first low pass filter having a bandwidth of approximately seven (7) Hz, coupled to an amplifier having a gain of approximately 1000, which is coupled to a second low pass filter having a bandwidth of approximately five (5) Hz. The first low pass filter having a bandwidth of seven (7) Hz and the second low pass filter having a bandwidth of five (5) Hz are sufficient to eliminate interference from gradient magnetic field pulses and / or radio frequency pulses introduced into the RESP signal 350.3. In some embodiments, the ECG AFE 310.1, the PPG AFE 310.2, and the RESP AFE 310.3 may include various radio frequency interference (RFI) and / or electrostatic discharge (ESD) circuit devices to protect the ECG AFE 310.1, the PPG AFE 310.2, and the RESP AFE 310.3 from RFI and / or ESD events. In these embodiments, analog circuits and / or circuitry may be used to implement RFI and / or ESD circuitry to protect the ECG AFE 310.1, PPG AFE 310.2, and RESP AFE 310.3 from RFI and / or ESD events, as will be apparent to those skilled in the relevant art(s) without departing from the spirit and scope of the present disclosure.

[0034] ADC 304 converts the processed (or processed) physiological event signal received from analog processing circuit device 302 from the analog signal domain to the digital signal domain to provide a digital physiological event signal to digital processing circuit device 306. Figure 3In the illustrated embodiment, ADC 304 includes ADC 312.1, ADC 312.2, and ADC 312.3. In some embodiments, ADC 312.1, ADC 312.2, and / or ADC 312.3 may be implemented as independent or discrete devices, and / or may be introduced or coupled to digital processing circuit device 306. As will be described in further detail below, digital processing circuit device 306 may be implemented using a dedicated processor chip, such as a digital signal processor (DSP) or an application-specific integrated circuit (ASIC) (as some examples). In some embodiments, the dedicated processor chip may include an on-chip ADC. In these embodiments, ADC 312.1, ADC 312.2, and / or ADC 312.3 may be implemented as discrete devices within gated signal transmitter 300 and / or implemented using an on-chip ADC of a dedicated processor chip.

[0035] ADC 312.1, ADC 312.2, and ADC 312.3 convert the processed ECG signal provided by ECG AFE 310.1, the processed PPG signal provided by PPG AFE 310.2, and the processed RESP signal provided by RESP AFE 310.3 from the analog signal domain to the digital signal domain, respectively. In some embodiments, ADC 312.1, ADC 312.2, and / or ADC 312.3 may be implemented as wideband ADCs having a sampling rate of, for example, about 8 kHz to capture interference introduced into ECG signal 350.1, PPG signal 350.2, and RESP signal 350.3, respectively. Figure 3 In the exemplary embodiment shown, ADC 312.1 may be implemented as a wideband ADC having a faster sampling rate than the sampling rates of ADC 312.2 and ADC 312.3 (e.g., approximately 1 kHz). In some embodiments, ADC 312.1, ADC 312.2, and / or ADC 312.3 may be implemented with different resolutions. For example, ADC 312.1 may be implemented with a twenty-four (24) bit resolution compared to the resolution of ADC 312.2 and ADC 312.3 (e.g., twelve (12) bit resolution). In some embodiments, the interference of the gradient magnetic field pulses and / or radio frequency pulses introduced into ECG signal 350.1 may be very large compared to ECG signal 350.1 itself. In these embodiments, the higher resolution of ADC 312.1 compared to ADC 312.2 and ADC 312.3 allows ADC 312.1 to adequately sample ECG signal 350.1 to capture interference introduced into ECG signal 350.1 by gradient magnetic field pulses and / or radio frequency pulses.

[0036] The digital processing circuitry 306 may process the digital physiological event signals received from the ADC 304 in the digital signal domain, such as by signal conditioning, to provide a clean physiological event signal to the communication transmitter 308. Figure 3 In the example embodiment shown, digital processing circuitry 306 includes gradient offset filter 314, gradient rejection filter 316, digital filter 318, downsampler 320, and combining circuitry 322. In some embodiments, gradient offset filter 314, gradient rejection filter 316, digital filter 318, downsampler 320, and combining circuitry 322 may be implemented as separate or discrete devices within digital processing circuitry 306, and / or may be incorporated into or coupled to a dedicated processor chip as described above.

[0037] In some embodiments, as described above, the PPG signal 350.2 and / or the RESP signal 350.3 may be assumed to be free of interference effects of gradient magnetic field pulses and / or radio frequency pulses compared to the ECG signal 350.1. In these embodiments, the digital PPG signal and the digital RESP signal received from the ADC 312.2 and the ADC 312.3, respectively, represent clean signals that are not significantly affected by interference effects of the gradient magnetic field pulses and / or radio frequency pulses. In these embodiments, the digital processing circuit device 306 may process the digital ECG signal received from the ADC 312.1 in the digital signal domain, for example, by signal conditioning, to provide a clean ECG signal free of interference effects of the gradient magnetic field pulses and / or radio frequency pulses, as will be described in further detail below.

[0038] The gradient offset filter 314 can compensate for signal offsets, such as common mode offsets, introduced into the ECG signal 350.1 by the gradient magnetic field pulses and / or the radio frequency pulses. In some embodiments, the gradient offset filter 314 can process samples of the digital ECG signal provided by the ADC 312.1 in the digital signal domain to reduce the signal offset introduced into the ECG signal 350.1 by the gradient magnetic field pulses and / or the radio frequency pulses. In some embodiments, the gradient offset filter 314 accumulates samples of the digital ECG signal provided by the ADC 312.1 within an interference time window. In these embodiments, the interference time window can have a duration of, for example, about two (2) milliseconds. In some embodiments, the gradient offset filter 314 evaluates the samples of the digital ECG signal provided by the ADC 312.1 accumulated during each time interference window according to the interference cost function to identify the samples that best represent the ECG signal 350.1 during each time interference window. In these embodiments, the interference cost function may evaluate, for each temporal interference window, the volatility of samples of the digital ECG signal provided by the ADC 312.1, the directional changes of samples of the digital ECG signal provided by the ADC 312.1, and / or the offsets between samples of the digital ECG signal provided by the ADC 312.1 to identify samples with minimal cost that best represent the ECG signal 350.1 without the interference of the gradient magnetic field pulses and / or the radio frequency pulses. An exemplary embodiment of the gradient offset filter 314 will be described below. Figure 4 Further described in .

[0039] The gradient rejection filter 316 can compensate for the gradient pulse interference introduced into the ECG signal 350.1 by the gradient magnetic field pulses and / or the radio frequency pulses. In some embodiments, the gradient rejection filter 316 can process the samples of the digital ECG signal provided by the gradient offset filter 314 in the digital signal domain to reduce the gradient pulse interference introduced into the ECG signal 350.1 by the gradient magnetic field pulses and / or the radio frequency pulses. In some embodiments, the gradient rejection filter 316 can use a nonlinear separation technique, such as a digital median filter as an example, on the samples of the digital ECG signal provided by the gradient offset filter 314 to compensate for the gradient pulse interference. In some embodiments, the gradient pulse interference can be characterized as impulse noise, such as salt and pepper noise or speckle noise, such as the impulse noise can be compensated by the gradient rejection filter 316. In some embodiments, for example, using a median filter, the median filter can analyze adjacent samples of a sample of the ECG signal samples provided by the gradient offset filter 314, also referred to as a median window, to determine the median value of these samples. In these embodiments, the median filter can replace the sample with the median of the median window. The median filter may iteratively advance the median window to other samples of the ECG signal provided by the gradient offset filter 314 to compensate for gradient pulse interference.

[0040] The digital filter 318 further filters the digital ECG signal received from the gradient rejection filter 316. In some embodiments, the digital filter 318 can be characterized as a linear filter, a causal filter, a non-causal filter, a time-invariant filter, a stable filter, an unstable filter, a finite impulse response (FIR) filter, and / or any other type of digital filter apparent to a person skilled in the relevant art without departing from the spirit and scope of the present disclosure. The digital filter 318 can include a digital low-pass filter, a digital high-pass filter, a digital band-pass filter, a digital band-stop filter, and / or any other digital filter topology apparent to a person skilled in the art without departing from the spirit and scope of the present disclosure. In some embodiments, the digital filter 318 can remove high-frequency noise (e.g., greater than 150 Hz) from the digital ECG signal received from the gradient rejection filter 316, such as impulse noise, flicker noise, and / or white noise as some examples. In some embodiments, the digital filter 318 is optional.

[0041] Downsampler 320 downsamples the digital ECG signal received from gradient rejector filter 316 or the digital ECG signal received from digital filter 318 to the sampling rate of ADC 312.1 and / or ADC 312.2. In some embodiments, downsampler 320 downsamples the sampling rate (e.g., eight (8) kHz) of the digital ECG signal received from gradient rejector filter 316 or the digital ECG signal received from digital filter 318 to match the sampling rate (e.g., one (1) kHz) of the digital PPG signal received from ADC 312.2 and / or the digital RESP signal received from ADC 312.3. In some embodiments, downsampler 320 is optional, such as when the sampling rates of ADC 312.1, ADC 312.2, and ADC 312.3 are the same.

[0042] The combining circuit device 322 combines the digital ECG signal received from the gradient rejection filter 316, the digital filter 318 or the downsampler 320, the digital PPG signal received from the ADC 312.2, and the digital RESP signal received from the ADC 312.3 to provide a physiological event signal for transmission. In some embodiments, the combining circuit device 322 can be implemented as a digital adder, such as a full adder, a half adder, a ripple carry adder, a carry lookahead adder, a carry-save adder, a quantum full adder, and / or any other suitable digital circuit capable of combining digital signals that is apparent to a person skilled in the relevant art without departing from the spirit and scope of the present disclosure.

[0043] The communication transmitter 308 formats the physiological event signal from the combined circuit device 322 to provide a clean physiological event signal 352 for transmission to a communication receiver, such as the above Figure 1In some embodiments, the communication transmitter 308 may transmit the clean physiological event signal 352 via a wireless communication network, a wired communication network, and / or any combination thereof, which is apparent to those skilled in the relevant art without departing from the spirit and scope of the present disclosure. In these embodiments, the wireless communication network may conform to, for example, a version of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 communication standard, such as 802.11a, 802.11b / g / n, 802.11h, and / or 802.11ac (collectively referred to as Wi-Fi), a version of the Bluetooth communication standard, and / or any other wireless communication standard or protocol apparent to those skilled in the relevant art without departing from the spirit and scope of the present disclosure. In these embodiments, the wired communication network may conform to, for example, a version of the standard or protocol of IEEE 802.10 (also known as Ethernet), and / or any other wired communication standard or protocol apparent to those skilled in the relevant art without departing from the spirit and scope of the present disclosure.

[0044] Example gradient shift filter that may be implemented within an example gated transmitter

[0045] Figure 4 A block diagram of an example gradient shift filter that may be implemented within an example gated transmitter according to some example embodiments of the present disclosure is graphically illustrated. Figure 1 The gradient magnetic field pulses and / or radio frequency pulses used by the imaging device 104 in the embodiment may be in the same manner as described above. Figures 1 to 3 In some embodiments, the gradient magnetic field pulse and / or the radio frequency pulse may introduce a signal offset, such as a common mode offset, into the one or more physiological event signals of the patient. In these embodiments, the signal offset may be between about fifty (50) milliseconds (ms) and about two hundred (200) ms. As will be described in further detail below, the gradient offset filter 400 may compensate for the signal offset introduced into the one or more physiological event signals by the gradient magnetic field pulse and / or the radio frequency pulse. In some embodiments, the gradient offset filter 400 may evaluate an interference cost function to identify samples of the one or more physiological event signals that best represent the one or more physiological event signals without the interference of the gradient magnetic field pulse and / or the radio frequency pulse. In these embodiments, the interference cost function may evaluate the volatility of the samples of the one or more physiological event signals, the directional changes of the samples of the one or more physiological event signals, and / or the offsets between the samples of the one or more physiological event signals to identify the samples that best represent the one or more physiological event signals without the interference of the gradient magnetic field pulse and / or the radio frequency pulse.

[0046] like Figure 4 As shown, the gradient offset filter 400 may include a sample queue 402, a statistics module 404, digital adder circuits 406 to 410, a monotonicity module 412, a cost function module 414, and a cost analysis module 416. References to "modules" herein should be understood to include at least one of software, firmware, hardware (as some examples, such as one or more circuits, microchips, and / or electronic devices), and / or any combination thereof. In some embodiments, the sample queue 402, the statistics module 404, the digital adder circuits 406 to 410, the monotonicity module 412, the cost function module 414, and / or the cost analysis module 416 may be implemented as discrete devices within the gradient offset filter 400 and / or integrated within a dedicated processor chip, as described above. In some embodiments, the gradient offset filter 400 may represent a processor as described above. Figure 3 An example embodiment of the gradient shift filter 314 described in .

[0047] The sample queue 402 accumulates digital ECG signals 450 (e.g., as described above). Figure 3 312.1 described above). Figure 4 The discussion will be described with respect to ECG signals, but persons skilled in the relevant art will recognize that the teachings herein are equally applicable to compensating for signal offsets introduced into PPG signals and / or RESP signals by gradient magnetic field pulses and / or radio frequency pulses without departing from the spirit and scope of the present disclosure. Figure 4 In the illustrated example embodiment, the sample queue 402 accumulates N samples of the digital ECG signal 450 within an interference time window, e.g., a set of samples of the digital ECG signal provided by the ADC 312.1. In these embodiments, the interference time window may have a duration of, for example, approximately two (2) milliseconds. In some embodiments, the sample queue 402 may be implemented as one or more first-in-first-out (FIFO) queues, one or more circular buffers, and / or any other suitable architecture apparent to one skilled in the relevant art without departing from the spirit and scope of the present disclosure.

[0048] The statistics module 404 calculates one or more statistical measurements of the samples of the digital ECG signal 450 accumulated in the sample queue 402. In some embodiments, the one or more statistical measurements may include a moving mean, a moving median, a moving average, a moving mean square, a moving root mean square, a moving variance, and / or a moving norm to provide some examples of the samples of the digital ECG signal 450 accumulated in the sample queue 402. In some embodiments, the statistics module 404 calculates one or more statistical measurements of the samples of the digital ECG signal 450 accumulated in the sample queue 402 during the temporal interference time window.

[0049] Digital adder circuits 406 to 410 combine various samples of the digital ECG signal 450 accumulated in the sample queue 402 and / or the one or more statistical measurements provided by the statistics module 404 to provide various input signals to the monotonicity module 412 and / or the cost function module 414. Figure 4 In the example embodiment shown, the digital adder circuit 406 subtracts the i-th sample of the digital ECG signal 450 accumulated in the sample queue 402 from the one or more statistical measurements (e.g., a moving average, for example) to provide an offset signal (OFFSET) to the cost function module 414. In some embodiments, the offset signal represents a deviation or offset of the i-th sample from the one or more statistical measurements (e.g., a moving average, for example) provided by the statistics module 404. Figure 4 In the illustrated example embodiment, the digital adder circuit 408 subtracts the i+1th sample of the digital ECG signal 450 accumulated in the sample queue 402 from the i-th sample of the digital ECG signal 450, and the digital addition circuit 410 subtracts the i+2th sample of the digital ECG signal 450 accumulated in the sample queue 402 from the i+1th sample of the digital ECG signal 450 to provide a first derivative signal (DV_0) and a second derivative signal (DV_1) to the monotonicity module 412 and the cost function module 414, respectively. In some embodiments, the first derivative signal and the second derivative signal may be used to indicate the trend of the samples of the digital ECG signal 450 accumulated in the sample queue 402, for example, whether the samples are increasing, decreasing, and / or changing direction.

[0050] The monotonicity module 412 determines the monotonicity of the samples of the digital ECG signal 450 accumulated in the sample queue 402, i.e., whether the samples are increasing, decreasing, and / or changing direction. In some embodiments, the interference time window may have a sufficient duration to capture interference introduced to the digital ECG signal 450 by multiple gradient magnetic field pulses and / or radio frequency pulses. In these embodiments, when the i-th sample to the i+2-th sample of the digital ECG signal 450 are decreasing, the samples indicate a single gradient magnetic field pulse and / or radio frequency pulse. In these embodiments, when the i-th sample to the i+2-th sample of the digital ECG signal 450 are changing direction, the samples indicate multiple gradient magnetic field pulses and / or radio frequency pulses. Figure 4 In the example embodiment shown, when the sign of the first derivative signal (DV_0) and the sign of the second derivative signal (DV_1) are not the same, the monotonicity module 412 determines that the i-th sample to the i+2-th sample of the digital ECG signal 450 are changing direction. Figure 4 As shown, the monotonicity module 412 provides a monotonicity signal (MONO) having different integer values ​​to the cost function module 414 according to whether the i-th sample to the i+2-th sample of the digital ECG signal 450 is changing direction. In some embodiments, when the i-th sample to the i+2-th sample of the digital ECG signal 450 is changing direction, the monotonicity module 412 sets the monotonicity signal to a relatively large integer value, such as ten (10). In these embodiments, the relatively large integer value is selectively selected to effectively exclude the i-th sample of the digital ECG signal 450 from being selected as the best representative of the digital ECG signal 450 without the interference of the gradient magnetic field pulse and / or the radio frequency pulse. In some embodiments, when the i-th sample to the i+2-th sample of the digital ECG signal 450 is not changing direction, the monotonicity module 412 sets the monotonicity signal to a relatively small integer value, such as one (1). In these embodiments, the relatively small integer value is selectively chosen to effectively allow the i-th sample of the digital ECG signal 450 to be selected as the best representative of the digital ECG signal 450 without interference from the gradient magnetic field pulses and / or radio frequency pulses.

[0051] The cost function module 414 may implement an interference cost function that maps the i-th sample of the digital ECG signal 450 to a real number (WEIGHT) that represents an estimate of the difference between the digital ECG signal 450 and the digital ECG signal 450 without the interference of the gradient magnetic field pulse and / or the radio frequency pulse. In some embodiments, the interference cost function may evaluate the volatility of the samples of the digital ECG signal 450, the directional changes of the samples of the digital ECG signal 450, and / or the offset between the digital ECG signals 450. In these embodiments, the interference cost function may be expressed as:

[0052] weight=((|DV_0|+|DV_1|*MONO)+|offset|) (1)

[0053] Wherein, weight represents an estimate of the difference as described above, |DV_0| and |DV_1| represent the absolute values ​​of the first derivative signal and the second derivative signal, respectively, MONO represents the monotonicity signal, and |offset| represents the absolute value of the offset signal. Similarly, in some cases, providing an illustrative example, a general cost function with weighting coefficients for derivative signals, offset signals, monotonicity signals, etc. may be useful. Thus, a*x+b*y+c*z may represent a cost function, where x, y, and z represent derivative, offset, and monotonicity signals, respectively, and where a, b, and c represent weights, and in some use cases, each signal may have a different weight.

[0054] The cost analysis module 416 analyzes the weights of the samples of the digital ECG signal 450 to identify the digital ECG signal 450 samples that best represent the digital ECG signal 450 without the interference of the gradient magnetic field pulse and / or the radio frequency pulse. In some embodiments, the cost analysis module 416 analyzes the weights of the samples of the digital ECG signal 450 during the time interference window to identify the digital ECG signal 450 samples that best represent the digital ECG signal 450 without the interference of the gradient magnetic field pulse and / or the radio frequency pulse during the time interference window. In some embodiments, the cost analysis module 416 analyzes the weights of the samples of the digital ECG signal 450 to identify the digital ECG signal 450 samples with the minimum weight during the time interference window, which are the best representatives of the digital ECG signal 450 without the interference of the gradient magnetic field pulse and / or the radio frequency pulse during the time interference window. In these embodiments, the cost analysis module 416 accumulates weights of samples of the digital ECG signal 450 during the time interference window and selects the digital ECG signal 450 sample with the smallest weight during the time interference window as the digital ECG signal 450 sample that best represents the digital ECG signal 450 without interference from the gradient magnetic field pulse and / or radio frequency pulse during the time interference window.

[0055] In some embodiments, the gradient offset filter can be implemented using a selection filter or an algorithm thereof, rather than using a cost function with a sliding window. Such an algorithm tends to make a selection based on a derivative signal and an offset criterion, rather than retaining the best sample within a sliding window, which can reduce the complexity of the implementation and have other benefits of efficiency and reduced computational overhead. Thus, for example, it may be desirable to implement a selection filtering algorithm in certain low-power embedded systems.

[0056] For the example selection filter, in a similar manner as described elsewhere herein, the offset signal can represent the deviation or offset of the i-th sample from one or more statistical measurements (e.g., a moving average) that can be provided by a statistics module or equivalent. In one embodiment, a digital adder circuit or equivalent can subtract the i-1th sample of the digital ECG signal 450 accumulated in a sample queue or any smaller memory (e.g., a circular buffer, etc.) from the i-th sample of the digital ECG signal 450 to provide a first derivative signal (DV_0). In addition, the adder circuit or equivalent can subtract the i-2th sample of the digital ECG signal 450 accumulated in the sample queue or buffer from the i-th sample of the digital ECG signal 450 to provide a second derivative signal (DV_1). As with other embodiments described elsewhere herein, the first derivative signal and the second derivative signal can be used to indicate the trend of the samples of the corresponding digital ECG signal 450, for example, whether the samples are increasing, decreasing, and / or changing direction.

[0057] Thus, in some embodiments using a selection filter, a sample may be selected as an acceptable output if it satisfies certain conditions regarding the selection criteria. For example, an offset reference value (REF) and a derivative limit value (DV_LIMIT) may be set as predetermined values ​​associated with the selection criteria. A sample (e.g., the i-th sample from the one or more statistical measurements) may be evaluated for any or all conditions specified by the predetermined selection criteria. For example, these conditions may be (as an example) that |DV_0| and |DV_1| are both less than DV_LIMIT, and that the offset value is defined by the difference between the sample value and the offset reference value (e.g., BUF[i]-REF, where 'i' refers to the position at which the i-th sample is stored in the buffer vector or array BUF[]).

[0058] Thus, by performing these calculations on a selection filter, outlier samples can be rejected while allowing more reliable samples to be retained, while also contributing to ease of implementation and improved computational efficiency. Other benefits of this implementation and its equivalents are readily recognized, and other implementations may be considered to achieve other tradeoffs within the various constraints of other computing devices (e.g., embedded systems). The examples provided herein are not exhaustive, but rather illustrative, and are intended to reject certain offsets, outliers, or gradient trends in certain sample data.

[0059] Example Gated Receiver That May Be Implemented in an Example MRI Imaging System

[0060] Figure 5 A block diagram of an example gated receiver that may be implemented within an example MRI imaging system according to some example embodiments of the present disclosure is graphically illustrated. As will be described in further detail below, a gated signal receiver 500 may recover a gated signal transmitted by a gated signal transmitter (e.g., as described above). Figure 1 In some embodiments, the gated signal receiver 500 can generate various clock signals from these physiological event signals, such as trigger signals, which can be used to synchronize the physiological event signals to one or more physiological events of the patient, such as the patient's heartbeat and / or breathing. Figure 5 In the illustrated embodiment, the gating signal receiver 500 may include a communication receiver 502 , an analog processing circuit device 504 , a trigger generation circuit device 506 , and a communication transmitter 508 .

[0061] The communication receiver 502 may receive one or more physiological event signals 550 provided by the gated signal transmitter. In some embodiments, the one or more physiological event signals 550 may include an ECG signal, a PPG signal, and / or an RESP signal. In these embodiments, the communication receiver 502 may recover the ECG signal, the PPG signal, and / or the RESP signal from the one or more physiological event signals 550. In some embodiments, the communication receiver 502 may receive the one or more physiological event signals 550 through a wireless communication network, a wired communication network, and / or any combination thereof that is obvious to a person skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In these embodiments, the wireless communication network may comply with, for example, a version of the Wi-Fi communication standard, a version of the Bluetooth communication standard, and / or any other wireless communication standard or protocol that is obvious to a person skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In these embodiments, the wired communication network may comply with, for example, a version of the Ethernet communication standard, and / or any other wired communication standard or protocol that is obvious to a person skilled in the relevant art, without departing from the spirit and scope of the present disclosure.

[0062] The analog processing circuit device 504 can process the one or more physiological event signals 550 in the analog signal domain, for example, by amplification and / or signal conditioning, to provide the processed physiological event signals to the ADC 304. In some embodiments, the analog processing circuit device 504 may include one or more analog filters to resolve or separate the ECG signal, the PPG signal, and / or the RESP signal from each other. In some embodiments, the one or more analog filters may include an analog low-pass filter, an analog high-pass filter, an analog band-pass filter, an analog band-stop filter, and / or any other analog filter topology that is obvious to a person skilled in the relevant art without departing from the spirit and scope of the present disclosure. For example, the one or more analog filters may include a high-pass filter with a cutoff frequency of about 0.1 Hz and a low-pass filter with a cutoff frequency of about 10 Hz to separate the ECG signal from the PPG signal and the RESP signal. As another example, the one or more analog filters may include a high-pass filter with a cutoff frequency of about 0.05 Hz and a low-pass filter with a cutoff frequency of about 10 Hz to separate the PPG signal from the ECG signal and the RESP signal. As yet another example, the one or more analog filters may include a high pass filter with a cutoff frequency of approximately 0.1 Hz and a low pass filter with a cutoff frequency between approximately 3 Hz to separate the ECG signal from the PPG signal and the RESP signal. In some embodiments, the analog processing circuit device 504 may include one or more automatic gain control (AGC) circuits to adjust the amplitude of the ECG signal, the PPG signal, and / or the RESP signal. In these embodiments, the one or more AGC circuits may adjust the amplitudes of the ECG signal, the PPG signal, and / or the RESP signal to be substantially similar to each other. In some embodiments, the analog processing circuit device 504 may include a combining circuit device to combine the ECG signal, the PPG signal, and / or the RESP signal for transmission to, for example, as described above. Figure 1 The MRI computer control system 106 described in.

[0063] The trigger generation circuit device 506 can process one or more physiological event signals 550 in the analog signal domain, for example, by amplification and / or signal conditioning, to provide one or more physiological event trigger signals. In some embodiments, the trigger generation circuit device 506 may include one or more analog filters to resolve or separate ECG signals, PPG signals, and / or RESP signals from each other. In some embodiments, the one or more analog filters may include an analog low-pass filter, an analog high-pass filter, an analog band-pass filter, an analog band-stop filter, and / or any other analog filter topology that is obvious to a person skilled in the relevant art without departing from the spirit and scope of the present disclosure. For example, one or more analog filters may include a band-pass filter having a bandwidth between about 2 Hz and about 30 Hz to separate the ECG signal from the PPG signal and the RESP signal. As another example, one or more analog filters may include a band-pass filter having a bandwidth between about 0.1 Hz and about 10 Hz to separate the PPG signal from the ECG signal and the RESP signal. As yet another example, one or more analog filters may include a band-pass filter having a bandwidth between about 0.1 Hz and about 3 Hz to separate the ECG signal from the PPG signal and the RESP signal. In some embodiments, the trigger generation circuit device 506 may include one or more trigger circuits for generating the one or more physiological event trigger signals from the ECG signal, the PPG signal and / or the RESP signal. In these embodiments, the one or more physiological event trigger signals may include an ECG trigger signal and a PPG trigger signal, which may be used to synchronize the ECG signal and the PPG signal to the patient's heartbeat, respectively, as will be recognized by those skilled in the relevant art without departing from the spirit and scope of the present disclosure. In these embodiments, the one or more physiological event trigger signals may include an RESP trigger signal, which may be used to synchronize the RESP signal to the patient's breathing, as will be recognized by those skilled in the relevant art without departing from the spirit and scope of the present disclosure. In some embodiments, the one or more trigger circuits may be characterized as converting ECG signals, PPG signals, and RESP signals from the analog signal domain to provide a trigger signal or clock signal in the digital signal domain. In some embodiments, the trigger generation circuit device 506 may include a combinational circuit device for combining the ECG trigger signal, the PPG trigger signal, and / or the RESP trigger signal for transmission to, for example, a digital signal as described above. Figure 1 The MRI computer control system 106 described in.

[0064] The communication transmitter 508 formats the ECG signal, PPG signal and / or RESP signal from the analog processing circuit device 504 and / or the ECG trigger signal, PPG trigger signal and / or RESP trigger signal from the trigger generation circuit device 506 for transmission to, for example, the above Figure 1 In some embodiments, the communication transmitter 508 may transmit these signals through a wireless communication network, a wired communication network, and / or any combination thereof that is obvious to a person skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In these embodiments, the wireless communication network may conform to, for example, a version of the Wi-Fi communication standard, a version of the Bluetooth communication standard, and / or any other wireless communication standard or protocol that is obvious to a person skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In these embodiments, the wired communication network may conform to, for example, a version of the Ethernet communication standard, and / or any other wired communication standard or protocol that is obvious to a person skilled in the relevant art, without departing from the spirit and scope of the present disclosure. In some embodiments, the communication transmitter 508 may include a signal converter, such as an electro-optical converter, to convert a signal from the analog processing circuit device 504 and / or a signal from the trigger generation circuit device 506 into an optical signal for transmission to the communication receiver.

[0065] Example computer system that can be used to implement electronic devices within an example MRI imaging system

[0066] Figure 6 A simplified block diagram of a computer system suitable for use with the embodiments described herein is shown in a graphical form according to some example embodiments of the present disclosure. Various electronic devices, such as the above Figure 1 The MRI computer system 106 and / or management workstation 108 described in the foregoing may be implemented in hardware, firmware, software, or any combination thereof. Figure 6 The discussion of describes an example computer system 610 that can be used with these electronic devices.

[0067] exist Figure 6In the illustrated example embodiment, the computer system 610 typically includes at least one processor 614 that communicates with a plurality of peripheral devices via a bus subsystem 612. Typically, at least the processor 614 may include or may be any of the following: a microprocessor, a graphics processing unit, or a digital signal processor, and their electronic processing equivalents, such as an application specific integrated circuit ("ASIC") or a field programmable gate array ("FPGA"). As used herein, the term "processor" refers to a tangible data and information processing device that typically uses sequence transformations (also referred to as "operations") to physically transform data and information. Data and information may be physically represented by electrical, magnetic, optical, or acoustic signals that can be stored, accessed, transferred, combined, compared, or otherwise manipulated by a processor. The term "processor" may refer to a single processor and a multi-core system or multi-processor array, including a graphics processing unit, a digital signal processor, a digital processor, or a combination of these elements. The processor may be electronic, for example, including a digital logic circuit device (e.g., binary logic), or analog (e.g., an operational amplifier).

[0068] The processor may also operate to a client or server, accessing or hosting any application and / or data through any delivery paradigm, including, but not limited to, remote or distributed cloud computing solutions; local or on-premises software; and may support performing related operations in a "cloud computing" environment or according to any "as a service" model (e.g., software as a service (SaaS), hosted software as a service (MSaaS), platform as a service (PaaS), desktop as a service (DaaS), framework as a service (FaaS), backend as a service (BaaS), mobile backend as a service (MBaaS), infrastructure as a service (IaaS), database as a service (DBaaS), etc.); and / or a hybrid model including any combination of the foregoing examples or other services or delivery paradigms.

[0069] By way of yet another example, at least some of the operations may be performed by a set of processors available on a distributed or remote system, accessible over a communications network (e.g., the Internet) and through one or more software interfaces (e.g., application program interfaces (APIs)), including, but not limited to, Document Object Model (DOM), Discovery Service (DS), NSUserDefaults, Web Services Description Language (WSDL), Message Exchange Pattern (MEP), Web Distributed Data Exchange (WDDX), Web Hypertext Application Technology Working Group (WHATWG) HTML5 Web Messaging, Representational State Transfer (REST or RESTful Web Services), Extensible User Interface Protocol (XUP), Simple Object Access Protocol (SOAP), XML Schema Definition (XSD), XML Remote Procedure Call (XML-RPC), or any other open or proprietary mechanism that may achieve similar functionality and results.

[0070] Any applicable data structures, file formats, and schemas may be derived from standards including, but not limited to, JavaScript Object Notation (JSON), Extensible Markup Language (XML), Another Markup Language (YAML), Extensible Hypertext Markup Language (XHTML), Wireless Markup Language (WML), MessagePack, XML User Interface Language (XUL), or any other functionally similar representation, alone or in combination. Alternatively, proprietary data structures, formats, or schemas may be used, either alone or in combination with known or open standards.

[0071] Such files may conform to a data model including, but not limited to, the Universal Data Model (UDM), the Item Attribute Value (EAV) model, the Object Attribute Value (OAV) model, a vertical database model, an open schema, a closed schema, or any other standard, non-standard, or proprietary data model. The configuration data may be structured, unstructured, a flat file database, a columnar database, a row database, or other type of database format.

[0072] Any relevant data, files and / or databases may be stored, retrieved, accessed and / or transmitted in a human-readable format, such as digital, textual, graphical or multimedia format, including various types of markup languages ​​and other possible formats. As an alternative or combination of the above formats, data, files and / or databases may be stored, retrieved, accessed and / or transmitted in a binary, encoded, compressed and / or encrypted format or any other machine-readable format.

[0073] Computer systems typically include an operating system and / or other low-level system software configured to support higher-level application software and to interface with system hardware and peripherals, such as managing memory access, input / output (I / O), and process scheduling.

[0074] like Figure 6 As shown, these peripheral devices may include a storage subsystem 624 (including a memory subsystem 626 and a file storage subsystem 628), a user interface input device 622, a user interface output device 620, and a network interface subsystem 616. The input and output devices allow a user to interact with the computer system 610. Figure 6 In the illustrated example embodiment, the network interface subsystem 616 provides an interface to an external network, including an interface to a communication network 618, and is coupled to corresponding interface devices in other computer systems or machines via the communication network 618. The communication network 618 may include many interconnected computer systems, machines, and communication links. These communication links may be wired links, optical links, wireless links, or any other device for information communication. The communication network 618 may be any suitable computer network, such as a wide area network such as the Internet, and / or a local area network such as Ethernet. The communication network 618 may be wired and / or wireless, and the communication network may use encryption and decryption methods, such as methods available for virtual private networks. The communication network uses one or more communication interfaces, which may receive data from other systems and send data to other systems. Embodiments of the communication interface typically include an Ethernet card, a modem (e.g., telephone, satellite, cable, or ISDN), a (asynchronous) digital subscriber line (DSL) unit, an IEEE1394 (Firewire) interface, a USB interface, and the like. One or more communication protocols may be used, such as HTTP, TCP / IP, RTP / RTSP, IPX and / or UDP.

[0075] The user interface input device 622 may include an alphanumeric keyboard, a keypad, a pointer device (e.g., a mouse, trackball, touchpad, stylus, or graphics tablet), a scanner, a touch screen incorporated into a display, an audio input device (e.g., a speech recognition system or microphone), eye movement recognition, brain wave pattern recognition, and other types of input devices. Such devices may be connected to the computer system by wire or wirelessly. In general, the use of the term "input device" is intended to include all possible types of devices and methods for inputting information into the computer system 610 or on the communication network 618. The user interface input device 622 typically allows a user to select objects, icons, text, etc. that appear on some type of user interface output device (e.g., a display subsystem).

[0076] The user interface output device 620 may include a display subsystem, a printer, a fax machine, or a non-visual display (e.g., an audio output device). The display subsystem may include a cathode ray tube (CRT), a flat panel device (e.g., a liquid crystal display (LCD)), a projection device, or some other device for creating a visible image (e.g., a virtual reality system). The display subsystem may also provide a non-visual display, such as through an audio output or a tactile output (e.g., vibration) device. In general, use of the term "output device" is intended to include all possible types of devices and ways of outputting information from the computer system 610 to a user or another machine or computer system.

[0077] The memory subsystem 626 typically includes a plurality of memories, including a main random access memory ("RAM") 630 (or other volatile storage device) for storing instructions and data during program execution and a read-only memory ("ROM") 632 for storing fixed instructions. The file storage subsystem 628 provides permanent storage for program and data files, and may include a hard drive, a floppy disk drive and associated removable media, a CD-ROM drive, an optical drive, flash memory, or a removable media cartridge. Databases and modules that implement the functionality of certain embodiments may be stored by the file storage subsystem 628.

[0078] The bus subsystem 612 provides a device that enables the various components and subsystems of the computer system 610 to communicate with each other as expected. Although the bus subsystem 612 is shown as a single bus in the schematic diagram, alternative embodiments of the bus subsystem can use multiple buses. For example, a RAM-based main memory can use a Direct Memory Access ("DMA") system to communicate directly with a file storage system.

[0079] in conclusion

[0080] The specific embodiments are described with reference to the accompanying drawings and in accordance with the exemplary embodiments of the present disclosure. References to "exemplary embodiments" in the present disclosure indicate that the described exemplary embodiments may include certain features, structures, or characteristics, but not every exemplary embodiment includes the certain features, structures, or characteristics. In addition, these phrases do not necessarily refer to the same exemplary embodiments. In addition, any features, structures, or characteristics described in connection with the exemplary embodiments may be included independently or in any combination with features, structures, or characteristics of other exemplary embodiments, whether or not explicitly described.

[0081] The detailed description is not intended to be limiting. Instead, the scope of the present disclosure is defined solely in accordance with the following claims and their equivalents. It should be understood that the detailed description section, rather than the abstract section, is intended to be used to interpret the claims. The abstract section may set forth one or more (but not all) exemplary embodiments of the present disclosure and, therefore, is not intended to limit the present disclosure and the following claims and their equivalents in any way.

[0082] The example embodiments described in this disclosure are for illustrative purposes only and are not intended to be limiting. Other example embodiments are possible, and the example embodiments may be modified while remaining within the spirit and scope of this disclosure. This disclosure has been described with the aid of functional building blocks, which illustrate the implementation of specific functions and their relationships. For ease of description, the boundaries of these functional building blocks are arbitrarily defined herein. Alternative boundaries may be defined as long as the specified functions and relationships are appropriately performed.

[0083] The embodiments of the present disclosure may be implemented in hardware, firmware, software applications, or any combination thereof. The embodiments of the present disclosure may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. The machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing circuit device). For example, the machine-readable medium may include a non-temporary machine-readable medium, such as a read-only memory (ROM), a random access memory (RAM), a disk storage medium, an optical storage medium, a flash memory device, etc. As another example, the machine-readable medium may include a transient machine-readable medium, such as a propagation signal (e.g., a carrier wave, an infrared signal, a digital signal, etc.) in electrical, optical, acoustic, or other forms. In addition, firmware, software applications, routines, instructions may be described herein as performing certain actions. However, it should be understood that such description is merely for convenience, and such actions are actually caused by other devices such as a computing device, a processor, a controller, or an execution firmware, software application, a routine, an instruction, etc.

[0084] The detailed description of the example embodiments sufficiently reveals the general nature of the present disclosure that others can easily modify and / or adapt these example embodiments for various applications by applying the knowledge of technicians in the relevant fields without undue experimentation and without departing from the spirit and scope of the present disclosure. Therefore, such adjustments and modifications are intended to be within the meaning and multiple equivalents of the example embodiments based on the teachings and guidance set forth herein. It should be understood that the words or terms in this document are for descriptive purposes and not for limitation, so that technicians in the relevant fields can interpret the terms or words in this specification in accordance with the teachings herein.

Claims

1. A magnetic resonance imaging (MRI) system for generating an anatomical image of a patient, the MRI system comprising: an imaging machine configured to apply a magnetic field and radio frequency waves to a patient within the imaging machine to acquire image data signals indicative of tissue composition within a spatial location of the patient; A gated signal transmitter configured to compensate for signal offset and gradient pulse interference introduced by the magnetic field and the radio frequency wave into a physiological event signal related to a physiological event of the patient to generate a noisy physiological event signal, the gated signal transmitter comprising: a digital gradient offset filter configured to identify a first plurality of samples of the noisy physiological event signal that best represents the physiological event signal from a second plurality of samples of the noisy physiological event signal for compensating for the signal offset, and a digital gradient rejection filter configured to perform a nonlinear separation technique on the first plurality of samples of the noisy physiological event signal to provide a third plurality of samples of the noisy physiological event signal for compensating for the gradient pulse interference, and A control system configured to: triggering the imaging machine to acquire the image data signal based on the third plurality of samples of the noisy physiological event signal, and The image data signals are converted into anatomical images for graphically illustrating tissue composition within the spatial location of the patient.

2. The MRI system according to claim 1, wherein: The digital gradient shift filter is configured to identify the first plurality of samples of the noisy physiological event signal during a plurality of interference time windows, each sample of the first plurality of samples of the noisy physiological event signal corresponding to a interference time window of the plurality of interference time windows.

3. The MRI system according to claim 1, wherein: The digital gradient shift filter is further configured to evaluate an interference cost function to identify the first plurality of samples of the noisy physiological event signal.

4. The MRI system according to claim 3, wherein: The interference cost function is configured to evaluate the volatility of samples in the second plurality of samples of the noisy physiological event signal, the directional changes of samples in the second plurality of samples of the noisy physiological event signal, and the offsets between samples in the second plurality of samples of the noisy physiological event signal in order to identify the first plurality of samples of the noisy physiological event signal.

5. The MRI system according to claim 4, wherein: The interference cost function is configured to evaluate the volatility of samples in the second plurality of samples of the noisy physiological event signal, the directional changes of samples in the second plurality of samples of the noisy physiological event signal, and the offsets between samples in the second plurality of samples of the noisy physiological event signal so as to determine multiple costs for the second plurality of samples of the noisy physiological event signal.

6. The MRI system according to claim 5, wherein: The digital gradient shift filter is configured to identify the first plurality of samples of the noisy physiological event signal as samples of the second plurality of samples of the noisy physiological event signal having a minimum cost among the plurality of costs during a plurality of temporal interference windows.

7. The MRI system according to claim 1, wherein: The digital gradient rejection filter comprises a median filter configured to: analyzing neighboring samples of a sample in the first plurality of samples of the noisy physiological event signal to determine a median of the neighboring samples; and Samples in the first plurality of samples of the noisy physiological event signal are replaced with medians of the adjacent samples to provide a third plurality of samples of the noisy physiological event signal.

8. A gated signal transmitter, comprising: analog processing circuitry configured to process electrocardiogram (ECG), photoplethysmogram (PPG), and respiration (RESP) signals received from a plurality of sensors attached to a patient to provide a processed ECG signal, a processed PPG signal, and a processed RESP signal; a plurality of analog-to-digital converters (ADCs) configured to convert the processed ECG signal, the processed PPG signal, and the processed RESP signal from an analog signal domain to a digital signal domain to provide a digital ECG signal, a digital PPG signal, and a digital RESP signal; A digital processing circuit arrangement configured to: The digital ECG signal is processed in the digital signal domain to compensate for the interference introduced into the ECG signal by the gradient magnetic field pulse and the radio frequency pulse to provide a clean ECG signal, and combining the clean ECG signal, the digital PPG signal, and the digital RESP signal to provide a physiological event signal; and A communication transmitter is configured to format the physiological event signal for transmission to a communication receiver.

9. The gating signal transmitter according to claim 8, wherein: The analog processing circuit device comprises: a first plurality of analog filters and a first amplifier configured to signal condition and amplify the ECG signal to provide said processed ECG signal; a second plurality of analog filters and a second amplifier configured to signal condition and amplify the PPG signal to provide said processed PPG signal; and A third plurality of analog filters and a third amplifier are configured to signal condition and amplify the RESP signal to provide the processed RESP signal.

10. The gate signal transmitter according to claim 8, wherein: The plurality of ADCs include: a first ADC configured to convert the processed ECG signal from an analog signal domain to a digital signal domain to provide the digital ECG signal; a second ADC configured to convert the processed PPG signal from an analog signal domain to a digital signal domain to provide the digital PPG signal; and A third ADC is configured to convert the processed RESP signal from an analog signal domain to a digital signal domain to provide the digital RESP signal.

11. The gate signal transmitter according to claim 10, wherein: The sampling rate of the first ADC is greater than the sampling rate of the second ADC and the sampling rate of the third ADC, wherein the resolution of the first ADC is greater than the resolution of the second ADC and the resolution of the third ADC, and Wherein, the digital processing circuit device comprises a downsampler configured to match the sampling rate of the clean ECG signal with the sampling rate of the digital PPG signal and the sampling rate of the digital RESP signal.

12. The gating signal transmitter according to claim 8, wherein: The digital processing circuit device comprises: a digital gradient offset filter configured to identify a first plurality of samples of the digital ECG signal that best represents the ECG signal from a second plurality of samples of the digital ECG signal for compensating for a signal offset introduced into the ECG signal by a magnetic field and a radio frequency wave, and A digital gradient rejection filter is configured to perform a nonlinear separation technique on the first plurality of samples of the digital ECG signal to provide a third plurality of samples of the digital ECG signal as a clean ECG signal for compensating for gradient pulses introduced to the ECG signal by magnetic fields and radio frequency waves.

13. The gating signal transmitter according to claim 8, wherein: The digital gradient shift filter is configured to identify the first plurality of samples of the digital ECG signal during a plurality of interference time windows, each sample of the first plurality of samples of the digital ECG signal corresponding to a interference time window of the plurality of interference time windows.

14. The gate signal transmitter according to claim 8, wherein: The digital gradient shift filter is further configured to evaluate an interference cost function to identify the first plurality of samples of the digital ECG signal.

15. The gating signal transmitter according to claim 14, wherein: The interference cost function is configured to evaluate the volatility of samples in the second plurality of samples of the digital ECG signal, the directional changes of samples in the second plurality of samples of the digital ECG signal, and the offsets between samples in the second plurality of samples of the digital ECG signal to identify the first plurality of samples of the digital ECG signal.

16. The gating signal transmitter according to claim 15, wherein: The digital gradient shift filter is configured to identify the first plurality of samples of the digital ECG signal as samples of the second plurality of samples of the digital ECG signal having minimum costs among the plurality of costs during a plurality of temporal interference windows.

17. The gating signal transmitter according to claim 8, wherein: The digital gradient rejection filter comprises a median filter configured to: analyzing adjacent samples of a sample in the first plurality of samples of the digital ECG signal to determine a median of the adjacent samples; and A sample of the first plurality of samples of the digital ECG signal is replaced with a median of the adjacent samples to provide the third plurality of samples of the digital ECG signal.

18. A digital gradient offset filter for compensating for a signal offset introduced into an electrical signal, the digital gradient offset filter comprising: a first digital adder configured to subtract a first sample of the electrical signal from the plurality of samples of the electrical signal from a moving average of the plurality of samples of the electrical signal to provide an offset signal; a second digital adder configured to subtract a second sample of the electrical signal from the plurality of samples of the electrical signal from the first sample to provide a first derivative signal; a third digital adder configured to subtract a third sample of the electrical signal from the plurality of samples of the electrical signal from the second sample to provide a second derivative signal; a monotonicity module configured to set a monotonicity signal to a first value when a sign of the first derivative signal is different from a sign of the second derivative signal, or to set the monotonicity signal to a second value when a sign of the first derivative signal is the same as a sign of the second derivative signal; a cost function module for implementing an interference cost function, the interference cost function mapping the first sample of the electrical signal to a weight using the offset signal, the first derivative signal, the second derivative signal, and the monotonicity signal, the weight representing an estimate of a difference between the first sample of the electrical signal and the first sample of the electrical signal without interference; as well as A cost analysis module is configured to compare the weight with other weights of other samples in the plurality of samples of the electrical signal to determine a sample in the plurality of samples that best represents the electrical signal without interference.

19. The digital gradient shift filter according to claim 18, wherein: The interference cost function includes: Weight = ((|DV_0|+|DV_1|*MONO)+|offset|) Where |DV_0| and |DV_1| represent the absolute values ​​of the first derivative signal and the second derivative signal, respectively. Among them, MONO represents a monotonic signal, Where |offset| represents the absolute value of the offset signal.

20. The digital gradient shift filter according to claim 18, wherein: The cost analysis module is configured to determine a sample among the plurality of samples that best represents an electrical signal without interference as a sample among the plurality of samples having a minimum weight.

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