SYSTEM AND METHOD FOR ADAPTING ECG DATA RATE BASED ON GRADIENT ACTIVITY - Patent application

Abstract

A system 400 for monitoring a physiological parameter of a patient, comprising a wireless signal unit 60, 500 including a transceiver 515 configured to transmit wireless data related to a physiological parameter of the patient over a communication link CL at a default transmission rate, a patient monitor 70 configured to receive the wireless data transmitted from the transceiver at the default transmission rate, and a processor 64, 505, 535 communicatively coupled to the wireless signal unit, the processor being configured to (i) receive and pre-process (650) an input signal including a signal corresponding to the physiological parameter of the patient and a transient gradient signal from a gradient system, (ii) determine (650) a gradient signal activity value of the gradient system, and (iii) dynamically adjust (670) a default transmission rate of the wireless data transmitted from the transceiver to an adjusted transmission rate based on the gradient signal activity value.

Description

[Technical field]

[0001]

[0001] The present disclosure relates generally to physiological signal monitoring in shielded environments. The present invention has application in combined electrocardiography (ECG) determination in magnetic resonance imaging and will be described with particular reference thereto. However, it will be appreciated that the present invention has application in other use scenarios and is not limited to the above application. More particularly, the present disclosure relates to a system and method for wirelessly monitoring medical and health data (e.g., vital signs and / or electrocardiogram data) in shielded areas, such as magnetic resonance (MR) examination rooms, by using digital signal processing resources to reduce data rates based on gradient signal activity. [Background technology]

[0002] Magnetic Resonance Imaging (MRI) systems use high power gradient systems to phase encode imaging data during acquisition. Unfortunately, these high power gradient signals couple to ECG leads used for patient monitoring during MRI image acquisition, resulting in gradient induced artifacts. These gradient signals increase the need for high dynamic range receivers and increase the effective number of bits (ENOB) of the received signal, which in turn requires a higher data rate to communicate the ECG data to the patient monitor. A higher data rate link is required to communicate the ECG data while maintaining the ECG information content. The system dynamic range must accommodate the small desired ECG signal in conjunction with high dynamic range interferers (e.g., high power gradient signals). Exacerbating this situation is that the frequency components of the gradient signals are at or very close to the desired ECG signal. Conventional data encoding techniques cannot be used without adversely affecting the desired ECG signal.

[0003]

[0003] A high dynamic range receiver with a high data rate communication link requires more power, thus increasing costs. For battery-powered ECG sensors, this higher power consumption increases the need for more charging cycles or battery replacements. The additional power consumption further reduces the throughput of the MRI system unless more expensive measures are adopted, such as incorporating additional sensors, chargers, or batteries. Summary of the Invention [Problem to be solved by the invention]

[0004]

[0004] Therefore, there is a need in the art for improved devices and systems for wirelessly monitoring medical and health data in shielded areas that are less expensive and more efficient. [Means for solving the problem]

[0005]

[0005] The present disclosure generally relates to an apparatus and system of the present invention for wirelessly monitoring one or more physiological signals of a patient in a shielded environment, such as a magnetic resonance environment, or any environment with intermittent distortion of one or more physiological signals of the patient. Various embodiments and implementations herein relate to an improved system or apparatus that uses digital signal processing to measure the signal dynamic range of the system during periods when transient gradient signals are present and when transient gradient signals are absent. An algorithm uses the value of the signal dynamic range during periods to adjust the data link rate during MRI image acquisition. The data link rate can be increased or maximized when transient gradient signals are present and decreased or reduced when transient gradient signals are absent during MRI image acquisition. The shielded environment can include a shielded magnet room, such as an MR room, including shielded walls including steel or copper or any suitable alternative. The algorithm is provided in or near a wireless ECG signal unit that can be placed inside the bore of the magnet during image acquisition. The wireless ECG signal unit wirelessly communicates signals corresponding to the patient's physiological parameters to a base unit or patient monitor located outside the bore of the MRI magnet but within a shielded room based on a dynamically adjustable transmission rate. Applicant has recognized and understood that the high dynamic range receiver and high data rate communication link of the wireless ECG signal unit are not always needed during MRI image acquisition, especially when no transient gradient signals are present. Applicant has further recognized and understood that by dynamically adjusting the transmission rate of the wireless data transmission based on the transient gradient signal activity, power consumption of the monitoring system may be significantly reduced.

[0006] In general, in one aspect, a wireless signal unit is provided that includes a transceiver and a processor configured to transmit wireless data related to a patient's physiological parameter over a communication link at a default data transmission rate within a patient information system, the processor being configured to receive and pre-process input signals including a signal corresponding to the patient's physiological parameter and a transient gradient signal from a gradient system, determine a gradient signal activity value of the gradient system, and dynamically adjust a default transmission rate of the wireless data transmitted from the transceiver to an adjusted data transmission rate based on the gradient signal activity value.

[0007] In one embodiment, the gradient system is part of a magnetic resonance imaging (MRI) system.

[0008] In one embodiment, the signal corresponding to a physiological parameter of the patient includes an ECG signal.

[0009]

[0009] In one embodiment, the adjusted data transmission rate includes a minimum rate required to communicate a signal corresponding to a physiological parameter, taking into account a data phase encoding process performed during the image acquisition process.

[0010]

[0010] In one embodiment, the transceiver is configured to transmit wireless data associated with the input signal to a patient monitor having a display, the patient monitor being part of a patient information system or connected to a patient information system.

[0011]

[0011] In one embodiment, the processor is further configured to determine a number of effective bits of the received input signal.

[0012]

[0012] In one embodiment, the processor is further configured to compare the determined number of significant bits of the received input signal to a predetermined or default maximum number of significant bits used when a transient gradient signal is present.

[0013]

[0013] In one embodiment, the processor is further configured to reduce the default data transmission rate when the determined number of effective bits of the received input signal is less than a predetermined or default maximum number of effective bits used when a transient gradient signal is present.

[0014]

[0014] In one embodiment, the processor is further configured to reduce the default transmission rate according to a predetermined reduced transmission rate associated with the determined number of effective bits of the received input signal.

[0015] In general, in another aspect, there is provided a system for monitoring a physiological parameter of a patient. The system includes a wireless signal unit having a transceiver configured to transmit wireless data related to the physiological parameter of the patient over a communication link at a default data transmission rate. The system further includes a patient monitor having a receiver and a processor configured to receive the wireless data transmitted from the transceiver of the wireless transceiver at the default data transmission rate. The processor of the system is communicatively coupled to the wireless signal unit and configured to (i) receive and pre-process input signals including a signal corresponding to the physiological parameter of the patient and a transient gradient signal from a gradient system, (ii) determine a gradient signal activity value of the gradient system, and (iii) dynamically adjust a default data transmission rate of the wireless data transmitted from the transceiver to an adjusted transmission rate based on the gradient signal activity value.

[0016] In one embodiment, the gradient system is part of a magnetic resonance imaging (MRI) system.

[0017] In one embodiment, the signal corresponding to a physiological parameter of the patient includes an ECG signal.

[0018]

[0018] In one embodiment, the adjusted data transmission rate includes a minimum rate required to communicate a signal corresponding to a physiological parameter, taking into account the data phase encoding process performed during the image acquisition process.

[0019]

[0019] In one embodiment, the patient monitor further includes a monitor processor configured to post-process the wireless data received from the transceiver, and a display configured to display the post-processed wireless data.

[0020]

[0020] In one embodiment, the processor is further configured to (i) determine a number of effective bits of the received input signal, (ii) compare the determined number of effective bits of the received input signal to a predetermined or default maximum number of effective bits used when a transient gradient signal is present, and (iii) reduce the default data transmission rate when the determined number of effective bits of the received input signal is less than the predetermined or default maximum number of effective bits used when a transient gradient signal is present.

[0021] In various embodiments, the processor or controller is associated with one or more storage media (generally referred to herein as "memory", e.g., volatile and non-volatile computer memory, e.g., RAM, PROM, EPROM, and EEPROM, floppy disks, compact disks, optical disks, magnetic tapes, etc.). In some embodiments, the storage media may be encoded with one or more programs that, when executed in one or more processors and / or controllers, perform at least some of the functions described herein. The various storage media may be fixed within the processor or controller, or may be movable such that one or more programs stored on the various storage media can be loaded into the processor or controller to perform the various aspects described herein. The term "program" or "computer program" is used herein in a generic sense to refer to any type of computer code (e.g., software or microcode) that can be used to program one or more processors or controllers.

[0022]

[0022] It should be understood that all combinations of the above concepts and additional concepts described in more detail below (provided that such concepts are not mutually inconsistent) are contemplated as part of the inventive subject matter disclosed herein. In particular, all combinations of subject matter recited in the claims at the end of this disclosure are contemplated as part of the inventive subject matter disclosed herein. It should also be understood that terms explicitly used in this specification that also appear in any disclosures incorporated by reference should be given the meaning most consistent with the determination concepts disclosed herein.

[0023]

[0023] These and other aspects of the various embodiments will be apparent from and will be elucidated with reference to the embodiments described hereinafter.

[0024] In the drawings, like reference characters generally represent the same parts throughout the different views. Further, the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments throughout. [Brief description of the drawings]

[0025] [Figure 1]

[0025] FIG. 1 is a schematic diagram of an exemplary collection of cardiovascular (cv) electrode patches according to an aspect of the present disclosure. [Diagram 2]

[0026] FIG. 1 is a schematic diagram of an exemplary standard cv electrode patch according to an embodiment of the present disclosure. [Diagram 3]

[0027] FIG. 2 is a schematic diagram illustrating an exemplary arrangement of a collection of cv electrode patches according to an embodiment of the present disclosure. [Figure 4]

[0028] FIG. 1 illustrates an embodiment of one or more electrode patches including a parallel lead processing system in a magnetic resonance (MR) environment in accordance with aspects of the present disclosure. [Diagram 5]

[0029] FIG. 1 illustrates a schematic diagram of a wireless signal unit of a lead processing system according to an aspect of the present disclosure. [Figure 6]

[0030] 1 is a flowchart of a method for dynamically adjusting a transmission rate of wireless data from a wireless transceiver according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026]

[0031] The present disclosure describes various embodiments of an improved system and apparatus for dynamically adjusting a wireless data transfer rate between a wireless ECG signal unit transmitting patient data and a patient monitoring unit receiving the patient data transmitted from the ECG signal unit. Applicant has recognized and understood that a high dynamic range receiver and a high data rate communication link of the wireless ECG signal unit are not always required during MRI image acquisition, especially when no transient gradient signals are present. Applicant has further recognized and understood that by dynamically adjusting the transmission rate of the wireless data transmission based on the transient gradient signal activity, the power consumption of the monitoring system may be significantly reduced. The improved apparatus and system includes a wireless signal unit having a transceiver configured to transmit wireless data related to a physiological parameter of the patient over a communication link to a patient information system, and a processor in communication with the wireless signal unit. The processor is configured to pre-process input signals including a signal corresponding to the physiological parameter of the patient and a transient gradient signal from a gradient system. The processor is further configured to (i) determine a gradient signal activity value of the gradient system, and (ii) dynamically adjust the transmission rate of the wireless data transmitted from the transceiver based on the gradient signal activity value. The improved apparatus and system provide the advantages described herein and others as will be appreciated.

[0027]

[0032] With reference to FIG. 1, a schematic representation of an exemplary collection of cardiovascular (cv) electrode patches is provided. FIG. 2 shows a schematic diagram of an exemplary standard electrode patch. In view of FIG. 1 and FIG. 2, the following can be understood: Electrode patches 10A, 10B, 10C, and 10D of FIG. 1 are typically provided for female and / or overweight patients with exemplary configurations. Patch 10E of FIG. 2 is typically provided for those patients who do not require the configuration shown in FIG. 1. Each of patches 10A-10E includes a flexible patch material or substrate made of a plastic or polymer layer and is configured to be attached to the skin of a patient. An adhesive coating layer may be provided for attachment. While each of patches 10A-10D in FIG. 1 includes electrodes 20A-20D, respectively, patch 10E includes four electrodes 30A-30D within the same patch. Each of electrodes 20A-20D is attached or formed in or on the center of the patch of patches 10A-10D, respectively. Electrodes 30A-30D are mounted or formed in or on each of the rounded corners of patch 10E. For example, electrode 30A is disposed or located in or on the top left rounded corner of patch 10E, electrode 30B is disposed or located in or on the top right rounded corner of patch 10E, electrode 30C is disposed or located in or on the bottom left rounded corner of patch 10E, and electrode 30D is disposed or located in or on the bottom right rounded corner of patch 10E. Any suitable configurations are contemplated and the present disclosure should not be limited by the configurations shown in FIGS. 1 and 2.

[0028]

[0033] Electrodes 20A-20D and 30A-30D of FIGS. 1 and 2 are configured to detect electrical activity of a patient's heart. The electrodes may include Ag-AgCL based electrodes or any suitable alternative. As shown in FIG. 3, patches 10A-10D and corresponding electrodes 20A-20D of FIG. 1 may be attached to a patient P in a suitable configuration to detect electrical activity of the patient's heart. Although not shown, patch 10E and corresponding electrodes 30A-30D of FIG. 2 may also be attached to a patient P in a similar suitable configuration to detect electrical activity of the patient's heart. In an embodiment, patch 10E may include an opening in the center, for example for a neonatal patient.

[0029]

[0034] Referring to FIG. 4, an embodiment of one or more electrode patches along with a lead processing system (LPS) in a magnetic resonance (MR) environment is shown. FIG. 4 shows a monitoring system 400 including a partially cutaway side view of an MRI scanner 40. The system 400 broadly comprises an MR scanner 40, one or more controllers C, a wireless signal unit 60, and a patient monitor 70. The system 400 further comprises a patient support for supporting the patient P for scanning and / or for positioning the patient P in a desired position and / or orientation relative to the scanner 40. In an embodiment, the positioning of the patient P is partially or fully controlled by the controller C. As described in more detail herein, the wireless signal unit 60 is configured to generate waveform signals from the detected electrical activity and to wirelessly transmit the waveform signals to the patient monitor 70 for display. Because the wires from the electrodes are conductive, the leads and other wiring are susceptible to interference currents induced by gradient field pulses applied to the patient P during image acquisition. Induced currents in the electrodes and / or electrode wires create gradient noise interference in the ECG signal. Interference from gradient pulses typically has an amplitude of about ±100 mV, but can reach as high as ±5 V. ECGs typically have an amplitude of about 300 uV to 5 mV peak-to-peak. To handle ECG signals with gradient noise interference, an analog-to-digital converter with a high dynamic range is required. Dynamic range represents the ratio between the maximum input signal and the inherent noise level, and can be expressed as an effective number of bits (ENOB). In an embodiment, an ADC with a high dynamic range (e.g., many effective bits), e.g., 16 bits, is used to accommodate small desired ECG signals with high dynamic range interferers (e.g., high power gradient signals). However, using a large number of bits requires a lot of power consumption and cost on an ongoing basis. The improved apparatus and system of the present application are configured to optimize the effective number of bits of the received signal, thereby optimizing the data rate required to communicate the minimum data rate without any impact on the desired ECG signal due to data encoding.

[0030]

[0035] The scanner 40 includes a bore located between both ends of the scanner. In an embodiment, both ends of the scanner 40 are open. The scanner 40 further includes a housing with a main magnet 44, a gradient coil 46, and a radio frequency (RF) coil 48. At least a portion of the patient P may be placed in an examination region of the MR scanner 40, such as a horizontal bore, vertical bore c-type, etc. The scanner 40 may further include a cooling mechanism (e.g., a cryo-cooling system). For example, the magnet 44 may include multiple magnets or superconducting coils located inside a cryo-shrouding. There are many different MRI scanner systems, i.e., panoramic systems, with different configurations. It should be understood that the present invention should not be limited in any manner by the configuration shown.

[0031]

[0036] The primary magnet 44 is configured to generate a static magnetic field oriented generally parallel to the cylindrical axis of the bore of the scanner 40. A resistive primary magnet may also be used in embodiments. The primary magnet 44 is an annular (e.g., ring-shaped) magnet. However, in other embodiments, the primary magnet 44 includes any suitable magnet or magnets, such as, for example, an annular magnet, a planar magnet, a split magnet, an open magnet, a semicircular magnet, etc. The primary magnet 44 may be made of any suitable material, such as, for example, a superconducting material, and / or operates under the control of the controller C.

[0032]

[0037] Gradient coils 46 may comprise x-, y-, and z-gradient coils configured to generate gradient magnetic fields along one or more corresponding axes under the control of controller C. The gradient magnetic fields manipulate and encode magnetic resonance in tissue of patient P. Coils 46 may be selectively configured by controller C to generate magnetic field gradients within the bore of the housing of scanner 40.

[0033]

[0038] Each of the one or more radio frequency (RF) coils 48 may be embodied as a body coil, a head coil, a surface coil, or another local coil for selectively inducing magnetic resonance. The one or more RF coils 48 may be configured as a transmit coil or an array of coils for generating RF excitation pulses for inducing magnetic resonance in tissue of the patient P. The RF coils 48 may be located within the bore of the scanner 40 to obtain an image of a desired scanning volume within the bore. A controller C may control the coils 48. In an embodiment, the scanner 40 further includes an RF transmitter 49 coupled to the one or more RF coils for selectively injecting RF excitation pulses into the patient being imaged.

[0034]

[0039] By selectively operating the magnetic field gradient coils 46 and the RF coils 48, magnetic resonance is generated and spatially encoded in at least a portion of a region of interest of the imaging patient P. By applying selected magnetic field gradients via the gradient coils 46, selected k-space trajectories, such as, for example, a Cartesian trajectory, multiple radial trajectories, a spiral trajectory, etc., may be traversed.

[0035]

[0040] The one or more controllers C may control the overall operation of the system 400 and include one or more logic devices, such as a processor (e.g., a microprocessor). The controller C may include one or more of a main magnet controller, a gradient controller, and an RF controller. The main magnet controller may control the operation of the main magnet 44. The gradient controller may control the operation of the gradient coil 46. The RF controller may control the operation of the RF coil 48. The one or more controllers C may include at least one controller, such as a system controller, formed integrally with the scanner 40 or independent of the scanner 40. For example, the controller may be located remotely from the scanner 40 and communicate with one or more components of the system, including the main magnet, the gradient coil, and the RF coil, via wired and / or wireless communication methods. Additionally, the controller may communicate with one or more of the above-mentioned elements via one or more networks (e.g., a wide area network (WAN), a local area network (LAN), the Internet, a proprietary communication bus, a controller area network (CAN), a telephone network, etc.). It should also be understood that the one or more control devices C may include at least one control device, such as a system control device, and may be formed integrally with the patient monitor 70 or any other component of the system 400, or may be formed independently from the patient monitor 70 or any other component of the system 400.

[0036]

[0041] Electrodes in the attached patch 10 detect electrical activity of the patient P's heart. Such electrical activity is transmitted from the electrodes to the cable 50 and to a wireless signal unit 60 or ECG monitoring device or ECG unit. The terms "unit" and "device" are used interchangeably herein to refer to elements 60 and 500. It should be understood that the ECG monitoring device 60 is preferably a handheld, battery-powered device configured to be in close proximity to the electrodes in the patient P and to be in the bore or outside the bore during MRI image acquisition. In FIG. 4, the device 60 is shown at a distance from the patient P for illustrative purposes only. In an embodiment, the device 60 includes a rechargeable accumulator or battery. As used herein, MRI image acquisition refers to the reconstruction of a two-dimensional or three-dimensional visualization of anatomical data contained in the magnetic resonance imaging data. The visualization may be performed using a computer.

[0037]

[0042] In an embodiment, the cable 50 transmits the ECG data stream directly to the processor 64 so that gradient activity can be extracted from the data stream, for example by the processor 505 and / or DSP 535 described below. In an embodiment where the ECG data stream flows directly to the processor 64, the processor may include a signal transition stage to convert the data stream from analog to digital before proceeding to further processing steps. It should also be understood that the analog to digital conversion during the signal transition stage may be performed prior to reception at the processor 64. In an alternative embodiment, the cable 50 may transmit the ECG data stream to a separate gradient receiver system, for example to circuitry in the ECG device 60 or to a receiver 62. In such an embodiment, the receiver 62 converts the current from the electrodes into ECG lead signals. In other words, the receiver 62 generates the waveform signals. The receiver 62 may comprise an RF receiving or receiver coil, for example a wireless MRI coil or an array of similar local coils. The receiver 62 may further include an RF receiving antenna 63 that may be tuned to the desired frequency of interest, i.e., the gradient signals generated by the MR system, and may have a corresponding appropriate bandwidth. In an embodiment, the antenna 63 may also be used for wireless communication with the controller C. In an embodiment, the device 60 may be equipped with a separate antenna for wireless communication with the controller C.

[0038]

[0043] In an embodiment, the components of the system 400, including the ECG sensor, device 60, patient monitor 70, and controller C, communicate wirelessly through a gateway connected to a network of a healthcare facility and / or transmitting data or information to a data storage for real-time or offline monitoring, control, or evaluation after storage. Wireless sensors are further advantageous since they avoid the use of conductive wires, which may otherwise couple with magnetic field gradients and heat up due to RF heating if improperly routed during an MR procedure.

[0039]

[0044] The receiver 62 may include or be coupled to various additional circuit elements described or otherwise contemplated herein. However, the present invention is not limited by the following illustrative examples. It should be understood that the additional circuit elements described or otherwise contemplated herein may additionally or alternatively be incorporated within the processor 64 and / or the patient monitor 70. In an embodiment, one or more additional circuit elements are included within the device 60 and one or more additional circuit elements are included within the patient monitor 70. In an embodiment, the one or more additional circuit elements included in the device 60 are pre-processing elements and the one or more additional circuit elements included in the patient monitor 70 are post-processing elements.

[0040]

[0045] The processor 64 of the device 60 may be configured to receive and pre-process the ECG signals and gradient signals corresponding to physiological parameters of the patient P. Any one or more of the circuit elements described herein may be integrated within the processor 64. In an embodiment, the ECG signals may be combined or separately and individually transmitted to a preamplifier that pre-amplifies the analog ECG signals detected from the ECG electrodes. In an embodiment, the preamplifier may be a high quality instrumentation amplifier that amplifies the differential signals present at the ECG signal electrodes. An embodiment of the system 400 may further include an inverter within the processor 64 to invert the common mode signals present in the signals. The system 400 may further include a high speed noise reduction filter or any suitable alternative to remove any unwanted frequencies and / or frequency components within the processor 64. For example, filters such as slew rate filters, band pass filters, and / or t-wave suppression filters may filter the ECG lead signals in parallel and simultaneously. After the filtering step, system 400 may include an offset amplifier within processor 64 to add an offset voltage to ensure that the voltage is within the input signal specifications of analog-to-digital converter (ADC) device 68. The complete waveform may then be digitized by ADC device 68. It should be understood that ADC device 68 may be integrated within processor 64 in some embodiments, or may be separate from processor 64 in alternative embodiments. It should further be understood that in embodiments device 60 may be a software defined transceiver, such that components that are traditionally implemented in hardware (e.g., filters, amplifiers, modulators / demodulators, detectors, etc.) may alternatively be implemented in software.

[0041]

[0046] In an embodiment, the processor 64 may further include additional circuitry to convert the signal to a wireless transmission medium, such as an RF or infrared transmission medium, or any other suitable medium. In an embodiment, the processor 64 includes an interference reduction circuit that receives the waveform signal, such as from the receiver 62, and interference from the magnetic resonance gradient pulses. The circuit may output a physiological signal with reduced or eliminated magnetic interference. The interference-reduced physiological waveform may be wirelessly transmitted via communication link CL to a patient monitor 70 that includes a display device 72. The patient monitor 70 includes an antenna or receiver 80 that receives the physiological waveform from the device 60. The patient monitor 70 may further include additional circuitry 82 that performs post-processing of the received physiological waveform so that the waveform may be displayed on the display 72.

[0042]

[0047] The display device 72 may be configured to display a corresponding human readable ECG waveform after appropriate processing. Examples of the display device 72 include computer monitors, television screens, touch screens, vector displays, flat panel displays, vacuum fluorescent displays (VF), light emitting diode (LED) displays, electroluminescent displays (ELD), plasma display panels (PDP), liquid crystal displays (LCD), organic light emitting diode displays (OLED), projectors, head mounted displays, and the like. In a preferred embodiment, the display 72 comprises an integrated LED widescreen (touch screen) display that displays the patient's vital signs in high resolution. In addition to the patient's vital signs, a battery level indicator of one or more batteries required to operate the monitor 70 and / or the unit 60 may be displayed. Furthermore, the display may further include an indicator representing the status of the communication link between the device 60 and the monitor 70. For example, one icon may be shown when the communication link is established and a different icon may be shown when the communication link is not yet established or is interrupted. The patient monitor 70 further includes a power on / off button.

[0043]

[0048] Processor 64 may receive MR cycle information from scanner 40 and / or one or more controllers C via connection 74. In an embodiment, connection 74 may be integrated within processor 64. In other embodiments, connection 74 may be independent of processor 64. The MR cycle information provides the basis for processor 64 to determine a gradient signal activity value of system 400 and to dynamically adjust the transmission rate of wireless data sent to patient monitor 70. In an embodiment, the gradient signal activity value represents the presence or absence of a gradient signal. Thus, when the gradient signal activity value indicates that an MR gradient signal is present, processor 64 does not reduce the transmission rate of the communication link. When the gradient signal activity value indicates that an MR gradient signal is not present, processor 64 may reduce the transmission rate of the communication link between device 60 and patient monitor 70.

[0044]

[0049] In an embodiment, the gradient signal activity value may represent the magnitude or size of the gradient signal. Thus, the gradient signal activity value may further represent whether or not the gradient signal meets a threshold value or is above a threshold value and / or how much the gradient signal meets or is above a threshold value. Thus, when the gradient signal activity value indicates that the MR gradient signal meets or is above a threshold value, the processor 64 enables the unit 60 to communicate with the patient monitor 70 at a default high data transmission rate. When the gradient signal activity value indicates that the MR gradient signal has fallen below the threshold value, the processor 64 reduces the rate at which the device 60 communicates with the patient monitor 70 from the default data transmission rate. The processor 64 may be configured to continuously monitor the gradient signal activity value during MRI image acquisition. The processor 64 may further derive the gradient signal activity value based on the timing of the applied MR sequence in an embodiment or any other suitable process. The processor 64 may reduce the transmission rate of the wireless communication link to a minimum rate required to transmit only the ECG without interference. In an embodiment, the 16 bits may be reduced to 5 or 6 bits. In an embodiment, when no transient gradient signal is present, the processor 64 may determine the number of effective bits of the signal received without interference from the gradient signal by determining the first non-zero number in the most significant bits. Any other suitable method of determining the number of effective bits of the signal received without interference from the gradient signal is similarly envisioned.

[0045]

[0050] The various circuit elements may be embodied by a programmed or configured microprocessor, microcontroller, graphic processing unit (GPU), application specific integrated circuit (ASIC), field programmable gate array (FPGA), etc. For example, one or more microprocessors or processors may be configured to filter a plurality of ECG lead signals, detect ECG lead signals in the filtered signals, detect gradient signal activity levels, determine a number of effective bits of signals without transient gradient signals, and adjust a transmission rate of wireless data transmitted from the transceiver based on the detected gradient signal activity level values. The processor may output the processed lead signals to the patient monitor 70 at a default transmission rate or one or more adjusted transmission rates.

[0046]

[0051] The memory and storage described herein are considered to be non-transitory machine-readable media. As used herein, the term non-transitory is meant to exclude transitory signals but encompass all forms of storage, including both volatile and non-volatile memory. The disclosed filtering, detection, computation, and selection techniques are preferably implemented using non-transitory storage media that store instructions (e.g., software) readable and executable by electronic data processing devices that implement the disclosed filtering, detection, computation, and selection techniques.

[0047]

[0052] FIG. 5 shows a schematic diagram of various components used in a wireless signal unit, such as device 60 described herein. The wireless signal unit of FIG. 5 is configured for use with system 400 to implement various methods described herein. The wireless signal unit 500 comprises a processor 505, a memory 510, a transceiver 515, an antenna 525, a signal detector 530, and a digital signal processor (DSP) 535. In an embodiment, the processor 505 and / or the DSP 535 are used to extract gradient signal activity from the ECG data stream from the electrodes. In an alternative embodiment, the device 60 may comprise or communicate with a separate gradient signal receiver system as described above.

[0048]

[0053] The processor 505 controls the operation of the unit 500 based on program instructions stored in the memory 510. The memory 510 may comprise a read only memory (ROM) and / or a random access memory (RAM) and / or a non-volatile random access memory (NVRAM) and provides instructions and data to the processor 505. The memory 510 may further include various memories, such as, for example, an L1, L2, or L3 cache or system memory. Thus, the memory 510 encompasses a static random access memory (SRAM), a dynamic RAM (DRAM), a flash memory, a read only memory (ROM), or other similar memory devices. The memory 510 may store, among other things, an operating system. The RAM may be used by the processor for temporary storage of data from the electrodes. It should be understood that various information described as being stored in the memory 510 may additionally or alternatively be stored in a separate memory device. According to an embodiment, the operating system includes code that, when executed by the processor 505, controls the operation of one or more components of the wireless monitoring system 400. The processor 505 performs logical and arithmetic operations based on program instructions stored in memory 510. The instructions are executable to perform the methods described herein. In embodiments in which the processor implements one or more of the functions described herein in hardware, it will be apparent that software described as corresponding to such functions in other embodiments may be omitted.

[0049]

[0054] The processor 505 comprises or is a component of a processing system including one or more processors. The one or more processors may be implemented using any combination of a microprocessor, a microcontroller, multiple microcontrollers, circuits, a digital signal processor (DSP) 535, a field programmable gate array (FPGA), a decision application specific integrated circuit (ASIC), a processor, multiple processors, a programmable logic device (PLD), a controller, a state machine, gated logic, discrete hardware components, special hardware finite state machines, or any other suitable components capable of performing computations or other manipulations of information. The processing system may further include a machine-readable medium for storing software. Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise, is to be construed broadly to mean any type of instruction. The instructions, when executed by the one or more processors 505, cause the processing system to perform various functions described herein.

[0050]

[0055] Although device 60, 500 and / or system 400 are generally shown including one of each of the described components, various components may be overlapped in various embodiments. For example, processor 505 includes multiple microprocessors configured to independently execute the methods described herein or configured to perform steps or subroutines of the methods described herein such that the multiple processors work together to achieve the functionality described herein. Furthermore, when one or more components are implemented by a cloud computing system, various hardware components reside in separate physical systems. For example, processor 505 and / or 535 may include a first processor in a first server and a second processor in a second server. Many other variations and configurations are possible.

[0051]

[0056] The unit 500 further comprises a transceiver 515 electrically coupled to an antenna 525 to enable transmission and reception of data between the unit 500 and the patient monitor 70 described herein. In an embodiment, the transceiver 515 may be divided into a communication unit 518 and a receiver 520, each electrically coupled to the antenna 525. The antenna 525 is integrated within the unit 500 or coupled to or attached to the unit 500. The transceiver 515 and / or the communication unit 518 include one or more devices for enabling communication with other hardware devices. For example, the transceiver 515 and / or the communication unit 518 include a network interface card (NIC) configured to communicate according to an Ethernet protocol. Alternatively, the transceiver 515 and / or the communication unit 518 implement a TCP / IP stack for communicating according to a TCP / IP protocol. Various alternative or additional hardware or configurations for the transceiver 515 and / or the communication unit 518 are envisioned.

[0052]

[0057] The unit 500 may further include a signal detector 530 and a digital signal processor 535. The signal detector 530 may be configured to detect and quantify signals received from the electrodes. The digital signal processor 535 may be configured to process the signals as described herein. The various components of the wireless unit 500 may be coupled together by a system bus 540, which may include a power bus, a control signal bus, and a status signal bus in addition to a data bus.

[0053]

[0058] With reference to Fig. 6, an embodiment of a method 600 of using a wireless unit 500 or device 60 in an MR environment is provided. The method of Fig. 6 represents a flow chart of a method 600 for using a wireless signal unit 60, 500 to dynamically adjust the transmission rate of wireless data to optimize the effective number of bits and thus the data rate of the signal received at the unit to reduce power consumption and make the device and system more efficient. It should be understood that in any method recited in the claims of this disclosure that includes more than one step or operation, the order of the method steps or operations is not necessarily limited to the order in which the method steps or operations are recited, unless expressly indicated otherwise. The wireless unit 60, 500 and system may be any of those described or otherwise contemplated herein.

[0054]

[0059] The wireless units described herein may comprise a processor configured to determine a gradient signal activity value of the gradient system and to dynamically adjust the transmission rate of wireless data transmitted from the transceiver of the unit based on the gradient signal activity value. In an exemplary embodiment, the processing hardware and / or software for determining the gradient signal activity may be located in programmable resources within one or more of the processors 64, 505, and / or 535. In alternative embodiments, the wireless transceiver may be configured to receive configuration information, data rates, etc. from any one or more of the processors 64, 505, and / or 535 independent of the transceiver. In such an embodiment, the processor 64, 505, and / or 535 is configured to determine a gradient signal activity value of the gradient system and to dynamically adjust the transmission rate of wireless data transmitted from the transceiver based on the gradient signal activity value. The wireless transceiver and / or communication unit may receive the dynamically adjusted transmission rate from the one or more processors.

[0055]

[0060] In step 610 of the method, a wireless monitoring system is provided in a healthcare facility. Providing the wireless monitoring system includes installing an MR system including an MR examination room including a shielding wall made of an electromagnetic interference (EMI) shielding material, not limited to copper or steel in the embodiment. Providing the wireless monitoring system further includes attaching one or more physiological sensors, such as electrocardiogram electrodes as shown in Figs. 1-3, to a patient in a suitable orientation to collect physiological data of the patient P. Providing the wireless monitoring system further includes connecting a wireless unit 60, 500 to the one or more physiological sensors and establishing a communication link CL between the wireless signal unit and the patient monitor 70. Both the wireless signal unit and the patient monitor are in the MR examination room for MRI applications. The patient monitor 70 is connected to a network of the healthcare facility.

[0056]

[0061] In method step 620, the patient is placed in the bore or equivalent and the image acquisition process of the MR system is initiated. The scanner's patient support may be positioned or adjusted as necessary before starting the image acquisition process.

[0057]

[0062] In method step 630, magnetic resonance is generated and spatially encoded in at least a portion of the patient's region of interest, for example, by selectively operating magnetic field gradient coils and RF coils.

[0058]

[0063] In method step 640, signals corresponding to physiological parameters of the patient are detected by one or more physiological sensors, e.g., ECG electrodes. The detected signals are received by a receiver coil or a processor of the wireless signal unit. Transient gradient signals from the MR system are further detected by the one or more physiological sensors.

[0059]

[0064] In method step 650, a processor of the wireless signal unit pre-processes the signal corresponding to a physiological parameter of the patient. The processor further determines the signal and / or gradient signal activity values ​​from the MR system. In an embodiment, connection 74 is used to provide data from the MR system. In other embodiments, the MR system data is obtained or otherwise accessed directly from the controller C or scanner 40. If the gradient signal activity values ​​indicate that a transient gradient signal is present, in method step 660, a transceiver of the wireless signal unit transmits pre-processed wireless data related to the input signal to the patient monitor at a default transmission rate. Such transmitted data is received by a receiver or transceiver of the patient monitor.

[0060]

[0065] In step 670 of the method, the processor continues to receive and preprocess signals corresponding to the patient's physiological parameters during the image acquisition process. If the subsequent gradient signal activity value (or for that matter the initial gradient signal activity value) indicates that the transient gradient signal is not present or is below a threshold value, the processor automatically adjusts or reduces the default data transmission rate, and the transceiver 515 transmits the preprocessed wireless data at the adjusted or reduced transmission rate. Such transmitted data is received by a receiver or transceiver of the patient monitor. The processor may be configured to determine a number of effective bits of the received signal when the transient gradient signal is not present, and to compare the determined number of effective bits with a predefined threshold or a default number of effective bits used when the transient gradient signal is present. When the transient gradient signal is not present and the number of effective bits for the received signal is less than the default number, the processor may reduce the transmission rate according to a rate or rate reduction associated with a smaller number of effective bits. For example, a plurality of transmission rates may be stored in a look-up table in the memory 510, each transmission rate corresponding to a number of effective bits for the received signal. In another embodiment, multiple transmission rate reductions may be stored in a look-up table in memory 510, with each transmission rate reduction corresponding to an effective number of bits for the received signal as compared to a default effective number of bits.

[0061]

[0066] For example, the look-up table may include a default effective number of bits (ENOB) equal to 16, the default ENOB being associated with a default transmission rate of X, representing the maximum value or 100%. The look-up table may further include a first reduced effective number of bits equal to 15, the first reduced ENOB being associated with a first transmission rate reduction expressed as a percentage of the default transmission rate. In such an embodiment, the first transmission rate reduction may be equal to 15 / 16, and the transmission rate may be adjusted to 93.75% of the maximum or default transmission rate. Similarly, the look-up table may include a second transmission rate reduction for a second reduced effective number of bits equal to 14. The second transmission rate reduction may be equal to 14 / 16, and the transmission rate adjustment associated with an ENOB of 14 may be 87.5% of the maximum or default transmission rate. The look-up table may include transmission rate values ​​for each effective number of bits assumed in the system, so that the processor does not need to repeatedly calculate them. In an embodiment where the look-up table includes absolute transmission rate values ​​rather than proportional values, the look-up table may include a transmission rate of Y for a first reduced number of significant bits equal to 15, another transmission rate of Z for a second reduced number of significant bits equal to 14, etc. The embodiment including absolute values ​​may be more appropriate in scenarios where the rate change from, for example, 16 bits to 15 bits is different than the rate change from 15 bits to 14 bits.

[0062]

[0067] In method step 680, a patient monitor 70 of the patient information system receives the pre-processed data from the transceiver 515 at a default data transmission rate or an adjusted data rate. The patient monitor 70 may perform post-processing steps so that the data can be presented on the display 72.

[0063]

[0068] The wireless unit 60, 500 may use any number of wireless protocols, including the IEEE 802.11 protocol. The IEEE 802.11 standard is a family of specifications created by the Institute of Electrical and Electronics Engineers Inc. for wireless local area networks in the 2.4 GHz and 5 GHz bandwidth space. The IEEE 802.11 standard is a method for connecting computers and other electronic devices to each other and / or the Internet at high speeds without the need for wires. Of course, it should be understood that the present disclosure is not limited to any one particular wireless protocol. Any suitable protocol is contemplated, including any suitable wireless communication technology, such as, for example, radio frequency identification (RFID) technology, Wi-Fi technology, Bluetooth technology, technology used by cellular telephone communication systems, e.g., cellular data technology, and proprietary links.

[0064]

[0069] All definitions defined and used herein should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the terms defined.

[0065]

[0070] As used in this disclosure, both in the specification and in the claims, the singular terms "a," "an," and "the" should be understood to mean "at least one."

[0066]

[0071] The term "and / or" as used in the specification and claims of this disclosure should be understood to mean "either or both" of the elements so conjoined, i.e., elements that are conjunctive in some cases and elements that are disjunctive in other cases. Multiple elements listed with "and / or" should be construed in the same manner, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present other than the elements specifically determined by the term "and / or," whether related or unrelated to the element specifically determined.

[0067]

[0072] As used in this disclosure, both herein and in the claims, "or" shall be understood to have the same meaning as "and / or" as defined above. For example, when items are distinguished by a list, "or" or "and / or" shall be interpreted as non-exclusive, i.e., including at least one of a number of elements or a list of elements, but also including more than one element and, optionally, including additional, unlisted items. Conversely, only items designated, for example, as "only one of" or "only one of," or, when used in the claims, as "consisting of," shall be interpreted as including only one element of a number of elements or a list of elements. In general, the term "or" as used herein shall be interpreted as indicating exclusive alternatives (i.e., "one or the other, but not both") only when modified by terms of exclusivity, such as "either," "one of," "only one of," or "only one of."

[0068]

[0073] As used in this disclosure, both herein and in the claims, the phrase "at least one" in a list of one or more elements should be understood to mean that at least one element is selected from any one or more of the elements included in the list of elements, and is not limited to including at least one of each of the elements specifically listed in the list of elements, and does not exclude any combination of elements in the list of elements. This definition further allows that there may optionally be elements other than those specifically identified in the list of elements to which the phrase "at least one" refers, whether related or unrelated to the specifically identified elements.

[0069]

[0074] In the claims and throughout the specification thus far, all transitional phrases, such as "comprising," "including," "having," "having," "containing," "involving," "holding," "composed of," etc., are understood to be non-exclusive, i.e., meaning including, but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be exclusive or semi-exclusive transitional phrases, respectively.

[0070]

[0075] While several embodiments of the present invention have been described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures for performing the functions and / or obtaining one or more of the results and / or advantages described herein, and each of such variations and / or modifications is deemed to fall within the scope of the embodiments of the present invention described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application or applications in which the teachings of the present invention are used. Those skilled in the art will recognize, or be able to ascertain, using no more than reasonable experimentation, many equivalents to the specific embodiments of the present invention described herein. It is therefore understood that the foregoing embodiments are presented by way of example only, and that within the scope of the appended claims and equivalents, the embodiments of the present invention may be practiced otherwise than as specifically described and claimed. The inventive embodiments of the present disclosure relate to each individual function, system, article, material, kit, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and / or methods is within the scope of the present disclosure, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

Claims

1. A transceiver that transmits wireless data related to a patient's physiological parameters via a communication link at a default data transmission rate within a patient information system, a processor, and a wireless signal unit comprising: wherein the processor receives and preprocesses an input signal including a signal corresponding to the physiological parameters of the patient and a transient gradient signal from a gradient system, determines a gradient signal activity value of the gradient system, and dynamically adjusts the default data transmission rate of the wireless data transmitted from the transceiver to an adjusted data transmission rate based on the gradient signal activity value by reducing the default data transmission rate in response to the gradient signal activity value indicating that the transient gradient signal does not exist or is below a threshold.

2. The wireless signal unit according to claim 1, wherein the gradient system is part of a magnetic resonance imaging (MRI) system.

3. The wireless signal unit according to claim 1, wherein the signal corresponding to the physiological parameters of the patient includes an ECG signal.

4. The wireless signal unit according to claim 1, wherein the adjusted data transmission rate includes the minimum rate required to communicate the signal corresponding to the physiological parameters, taking into account a data phase encoding step performed during an image acquisition step.

5. The wireless signal unit according to claim 1, wherein the transceiver transmits the wireless data related to the input signal to a patient monitor equipped with a display, and the patient monitor is part of the patient information system or is connected to the patient information system.

6. The wireless signal unit according to claim 1, wherein the processor further determines the number of valid bits of the received input signal.

7. The wireless signal unit according to claim 6, wherein the processor further compares the determined number of valid bits of the received input signal with a predetermined or default maximum number of valid bits used when the transient gradient signal exists.

8. The wireless signal unit according to claim 7, wherein the processor further reduces the default data transmission rate when the determined number of valid bits of the received input signal is less than the predetermined or default maximum number of valid bits used when the transient gradient signal exists. ​ ​ ​ ​ ​ ​ The wireless signal unit according to claim 7.

9. The processor further reduces the default transmission rate according to a predetermined reduced transmission rate related to the determined number of valid bits of the received input signal. The wireless signal unit according to claim 8.

10. A system for monitoring a patient's physiological parameters, A wireless signal unit comprising a transceiver that transmits wireless data related to the patient's physiological parameters over a communication link at a default data transmission rate, A patient monitor comprising a receiver that receives the wireless data transmitted from the transceiver of the wireless transceiver at the default data transmission rate, A processor communicatively coupled to the wireless signal unit, The processor (i) receives and preprocesses an input signal including a signal corresponding to the patient's physiological parameters and a transient gradient signal from a gradient system, (ii) determines a gradient signal activity value of the gradient system, and (iii) in response to the gradient signal activity value indicating that the transient gradient signal does not exist or is less than a threshold, reduces the default data transmission rate to dynamically adjust the default data transmission rate of the wireless data transmitted from the transceiver to an adjusted data transmission rate based on the gradient signal activity value.

11. The gradient system is part of a magnetic resonance imaging (MRI) system. The system according to claim 10.

12. The signal corresponding to the patient's physiological parameters includes an ECG signal. The system according to claim 10.

13. The adjusted data transmission rate includes the minimum rate required to communicate the signal corresponding to the physiological parameters, taking into account a data phase encoding step performed during an image acquisition step. The system according to claim 10.

14. The patient monitor A monitor processor that post-processes the wireless data received from the transceiver, A display that displays the post-processed wireless data, And further comprises The system according to claim 10.

15. The processor further: (i) determines the number of significant bits of the received input signal; (ii) compares the determined number of significant bits of the received input signal with a predetermined or default maximum number of significant bits used when the transition gradient signal is present; and (iii) reduces the default data transmission rate when the determined number of significant bits of the received input signal is less than the predetermined or default maximum number of significant bits used when the transition gradient signal is present. The system according to claim 10.

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