WO2019057681A1

WO2019057681A1 - Signal monitoring leads with dissipative covers

Info

Publication number: WO2019057681A1
Application number: PCT/EP2018/075124
Authority: WO
Inventors: Sandra Simon HALLIBURTON; Michael Wilson; James Thomas Richards; David Dennis SALK; Steven J. Utrup; Dava Darlene EDWARDS SMITH
Original assignee: Koninklijke Philips N.V.
Priority date: 2017-09-21
Filing date: 2018-09-18
Publication date: 2019-03-28

Abstract

A lead set (622) for transferring an electrical biological signal from an electrode to a monitoring device, comprises: an electrode connector (702), a monitor connector (710), a cable (623), and an electro-static dissipative cover (704, 708). The electrode connector is configured to electrically connect to an electrode (206-210; 618). The monitor connector is configured to electrically connect to a monitor (624). The cable has a first end electrically coupled to the electrode connector and a second end electrically coupled to the monitor connector. The static-dissipative cover is configured to cover at least one of the electrode connector or the cable.

Description

SIGNAL MONITORING LEADS WITH DISSIPATIVE COVERS

FIELD OF THE INVENTION

The following generally relates to signal monitoring leads with dissipative covers and is described with particular application to electrocardiography, but is also amenable to other applications which record bio-electrical signals such as

electroencephalography, electromyography, etc.

BACKGROUND OF THE INVENTION

Some medical procedures require the detection of electrical signals produced by a subject. These electrical signals include, but are not limited to, an electrocardiogram (ECG) signal produced by the heart, an electroencephalogram (EEG) signal produced by the brain, and an electromyogram (EMG) signal produced by the muscles. These signals are sensed by electrodes placed on the body of the subject. The electrical signals are transmitted to a medical instrument for processing by a lead set, which includes a cable with electrical connectors on each end, and which attaches to the electrodes on the body of the subject and the medical instrument via the electrical connectors. The number of leads in a set generally matches the number of electrodes employed and varies according to the type of signal measured and the clinical task. The following describes an example in connection with electrocardiography and computer tomography (CT).

FIGURE 1 shows an example of a "normal" ECG waveform 100 for three cardiac cycles 102, 104, and 106, where a y-axis represents amplitude (e.g., in millivolts) and an x-axis represents time. In FIGURE 1, each of the cardiac cycles 102-106 has a systolic period 108 in which the atria (P wave 110) and subsequently the ventricles (QRS complex 112) contract and the ventricles then repolarize (the T wave 114), and a diastolic period 116 in which the heart relaxes and refills with circulating blood. For prospectively gated cardiac scans, an R peak 118 of the QRS complex 112 is identified in the waveform 100, e.g., based on its amplitude, and used to trigger a scan for a predetermined acquisition window within a quiet phase 120 of the heart in which motion of the heart is relative low compared to the motion during other phases of heart. For a retrospectively gated cardiac scan, the heart is scanned and the projection data is synchronized with the waveform 100 so that after the scan the R peak 118 can be identified and used to retrieve projection data for the reconstruction window.

The number and placement of the electrodes on the patient depends on whether a 3, 4, 5 or 12-lead configuration is used. FIGURE 2 shows an example of ECG electrode placement on a patient 200 relative to the heart 202 for a 4-lead configuration. The illustrated configuration includes a right arm electrode 204, a left arm electrode 206, a right leg electrode 208 and a left leg electrode 210. FIGURE 3 shows a cross-sectional view along a line A-A of the electrode 206 in FIGURE 2. As shown in FIGURE 3, the example electrode 206 also includes a bio-adhesive 220, an electrically conductive gel pad 222, and an electrically conductive linkage between the electrically conductive contact 214 and the electrically conductive gel pad 222. Electrode 206 further includes an electrically conductive contact 214 with a groove 215 approximately centered on a support 216. In this example, the support 216 has a circular disk shape. In FIGURE 2, all of the electrodes 204- 210 are located outside of a path 212 of the X-ray beam. FIGURE 4 shows an example where all of the electrodes but one (the electrode 208) are in the path 212 of the X-ray beam.

The electrical signals produced by the heart are low amplitude signals (e.g., less than five millivolts) and can be degraded by various noise sources. Examples of noise sources include electrostatic charge from patient clothing, bedding, and/or from a clinician, and, in the presence of X-rays, e.g., during a CT scan, the air surrounding the electrodes, which is ionized by the X-rays. This electrostatic charge can build up on the electrodes. The built up electrostatic charge has been detected along with the electrical signal. FIGURE 5 depicts an example ECG waveform 500 corrupted from such electrostatic charge. In this instance, a peak 502, caused by electrostatic discharge, may be identified as an R peak since it has a magnitude that is greater than the threshold used to identify R peaks. The false R peak could be interpreted as an arrhythmia. With prospectively gated cardiac CT, a false R peak may trigger a scan that is at least partially outside of the quiet phase or cause scan termination. With retrospective helical data acquisition, X-rays are on during the entire acquisition but are typically modulated downward during non-quiet phases. Unfortunately, misidentification of R peaks could cause unwanted downward modulation of tube current during a quiet phase rendering data during that phase useless and forcing reconstruction of projection data acquired at least partially outside of the quiet phase.

In both cases, the electrostatic discharge can result in degradation of image quality (e.g., increased motion artifact), which may render the reconstructed image data not well suited for diagnostic purposes. These instances may lead to a rescan at a same location, resulting in an additional radiation dose as well as a contrast dose administration.

SUMMARY OF THE INVENTION

In one aspect, a lead set for transferring an electrical biological signal from an electrode to a monitoring device, includes an electrode connector, a monitor connector, a cable, and an electro-static dissipative cover. The electrode connector is configured to electrically connect to an electrode. The monitor connector is configured to electrically connect to a monitor. The first end of the cable is electrically coupled to the electrode connector and a second end electrically coupled to the monitor connector. The static- dissipative cover is configured to cover at least one of the electrode connector or the cable.

In another aspect, a method includes sensing an electrical biological signal from an electrode with a lead set that includes an electrode connector, a cable, a monitor connector, and an electro-static dissipative configured to cover at least one of the electrode connector or the cable, processing the sensed electrical biological signal, and outputting the processed electrical biological signal.

In another aspect, a computer readable storage medium is encoded with computer readable instructions, which, when executed by a processer, cause the processor to: sense an electrical biological signal from an electrode with a lead set that includes an electrode connector, a cable, a monitor connector, and an electro-static dissipative configured to cover at least one of the electrode connector or the cable, process the sensed electrical biological signal, and output the processed electrical biological signal.

Aspects described herein address the above-referenced problems and/or others.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may take form in various components and arrangements of components, and in various steps and arrangements of steps. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.

FIGURE 1 schematically illustrates an example "normal" ECG waveform. FIGURE 2 schematically illustrates example placement of ECG electrodes on a subject outside of the X-ray beam path.

FIGURE 3 schematically illustrates an example ECG electrode. FIGURE 4 schematically illustrates example placement of the ECG electrodes on a subject with at least one electrode in the X-ray beam path.

FIGURE 5 schematically illustrates an example of a normal ECG waveform corrupted with static charge.

FIGURE 6 schematically illustrates an example system including an imaging scanner, an ECG monitor device, and ECG leads with dissipative covers.

FIGURE 7 schematically illustrates an example of an ECG lead with a dissipative electrode connector cover and a dissipative cable cover.

FIGURE 8 schematically illustrates an example of an electrode connector of the ECG lead without the dissipative electrode connector cover.

FIGURE 9 schematically illustrates another embodiment of an ECG lead with a dissipative electrode connector cover and a dissipative cable cover.

FIGURE 10 schematically illustrates a cross sectional view of a dissipative electrode connector cover in connection with an electrode.

FIGURE 11 schematically illustrates a cross sectional view of another dissipative electrode connector cover in connection with an electrode.

FIGURE 12 schematically illustrates a cross sectional view of yet another dissipative electrode connector cover in connection with an electrode.

FIGURE 13 schematically illustrates ECG lead with only a dissipative cable cover.

FIGURE 14 illustrates a method in accordance with an embodiment(s) herein. FIGURE 15 schematically illustrates an example of one arm of an electrode connector and a conductor. DETAILED DESCRIPTION OF EMBODIMENTS

FIGURE 6 illustrates an imaging system 600 such as a computed tomography (CT) scanner. The illustrated system 600 includes a generally stationary gantry 602 and a rotating gantry 604. The rotating gantry 604 is rotatably supported by the stationary gantry 602 via a bearing or the like and rotates around an examination region 606 about a longitudinal or z-axis 608 and emits radiation.

A radiation source 610, such as an x-ray tube, is supported by the rotating gantry portion 604 and rotates therewith. The radiation source 610, as it rotates around the examination region 606, emits radiation that traverse the examination region 606. The radiation source 610 can also emit radiation while the rotating gantry 604 is at a static position, for example, for a pilot, scout, and/or or other scan.

A radiation source controller 612 selectively turns radiation on and off. For example, the radiation source controller 612 can "gate" the radiation source 610, based on a gating signal, to selectively turn x-rays on to acquire data only in an acquisition window. The gating signal can be generated, e.g., in response to detecting an R peak in an ECG signal and cause the imaging system 600 to scan the heart during a predetermined acquisition window during a quiet phase of the heart for a prospectively gated cardiac CT scan.

An X-ray radiation sensitive detector array 614 subtends an angular arc opposite the examination region 606 relative to the radiation source 610. The illustrated X- ray radiation sensitive detector array 614 includes a one or two-dimensional array of photosensitive pixels. The X-ray radiation sensitive detector array 614 detects the X-ray radiation traversing the examination region 606 and generates projection data, or a signal, indicative thereof.

A subject support 616, such as a couch, supports a subject, such as a human or animal, or an object within the examination region 606. The subject support 616 is movable horizontally and/or vertically, which enables an operator or the system to load a subject, suitably position the subject within the examination region 606 before, during and/or after scanning, and unload the subject.

ECG electrodes 618 (e.g., similar to those shown in FIGURES 2-4) are disposed on a subject 620 and sense cardiac electrical activity. A lead set 622 includes electrode connectors (not visible in FIGURE 6) that are configured to attach to the electrodes 618, cables 623, and monitor connectors (not visible in FIGURE 6). The lead set 622 routes electrical signals from the electrodes 618 to a monitor 624. The monitor 624 processes the electrical signals and generates a waveform, e.g., similar to the ECG waveform 100 shown and described in connection with FIGURE 1. As described in greater detail below, the electrode connectors, the cables, or both the electrodes and the cables include dissipative covers, which dissipate static charge, such as static charge resulting from X-rays ionizing air surrounding the electrodes 618. As such, in one instance, the lead set mitigates static charge distortion of the ECG signal. This may prevent the system from incorrectly identifying a peak due to static charge as an R peak. In one instance, this may mitigate scan termination or modulation of the tube current downward during a quiet phase, motion artifact, sub-optimal contrast, and a rescan. A computing system serves as an operator console 626 and allows a user to select an imaging protocol such as a prospectively and/or retrospectively gated cardiac CT protocol. In a variation, wherein the electrodes 618 are ECG electrodes, the illustrated operator console 626 includes an R peak identifier 628 and a scan start time determiner 630. The R peak identifier 628 identifies R peaks in the waveform and generates a trigger signal indicative thereof for prospectively gated scans. For prospectively gated scans, a scan start time determiner 630 determines a start time for an acquisition window based on the trigger signal and/or other information such as a time delay from the R peak. Where the system is configured only for retrospectively gated cardiac CT scans, the scan start time determiner 630 can be omitted.

A reconstructor 632 reconstructs the projection data and generates volumetric image data indicative thereof. For prospectively gated cardiac CT, this includes

reconstructing the projection data for the scan of the acquisition window within the quiet phase triggered by the R peak of the waveform from the biological electrical signals. For retrospectively gated cardiac CT, this includes identifying projection data corresponding to the acquisition window within the quiet phase based on the biological electrical signals, which is synchronized with the projection data from the scan. The resulting volumetric image data can be visually presented via a display monitor, stored in a data repository (e.g., a picture and archiving communication system, or PACS), etc.

FIGURES 7 and 8 schematically illustrate an example of a single lead 700 of the lead set 622. The lead 700 includes an electrode connector 702 (visible only in FIGURE 8) with a dissipative electrode cover (coating, film, treatment, part of the connector, etc.) 704 (FIGURE 7), a cable (lead wire, etc.) 623 (a portion of which is visible only in FIGURE 8) with a dissipative cable cover (coating, film, treatment, part of the connector, etc.) 708 (FIGURES 7 and 8), and a monitor connector 710 (FIGURE 7 only) configured to interface with the monitor 624 (FIGURE 6). FIGURE 8 shows an electrically conductive cable shield 802 in connection with the cable 623. The cable shield 802 is also in connection with the shield 714 (not visible).

In FIGURE 7, the cable 623 is entirely surrounded by the dissipative cable cover 708, and the electrode connector 702 is covered with the dissipative cover 704 except at a region 709 where electrically conductive gripping ends 712 of the electrode connector 702 are exposed. Furthermore, the dissipative electrode cover 704 includes a shield 714, which forms a disk like structure on which the electrode connector 702 is disposed. The illustrated shape of the shield 714 is for explanatory purposes and not limiting. In general, the shape is such that it covers at least part of the electrode support 216 (FIGURE 2), as described in greater detail below. In a variation, the electrode connector 702 comprises of a static dissipative material, which is electrically connected to the gripping ends 712, and the electrode cover 704 is omitted.

In this example, the electrode connector 702 includes two elongated arms 716 mechanically connected via a "U" shaped elastic member 718 attached to inner sides 720. A distal end 722 of one of the arms 716 houses a portion of the cable 623. The cable 623 includes a conductor 1502 (FIGURE 15) that is electrically connected to the gripping ends 712. Proximal ends 724 of the arms 716 curve towards each other, and the exposed gripping ends 712 are at the ends of the proximal ends 724. In a "normal" state, the exposed gripping ends 712 are separated by a gap 726 having a distance less than a diameter of an electrical contact 214 (FIGURE 2) of the electrode 204-210 and/or 618 (FIGURES 2-4 and 6). An opening 728 in the cover 704 (FIGURE 7) provides visual access under the electrode connector 702.

The electrode connector 702 is configured such that urging the distal ends 722 towards each other (e.g., pinching them together), causes the proximal ends 724 to separate, increasing the distance 726 there between. This allows the electrode connector 702 to be readily connected to the electrical contact 214 (FIGURE 2) via the gripping ends 712.

Releasing the distal ends 722 allows the gripping ends 712 to grip the electrical contact 214. A second elastic member 732, comprised of and/or covered with the dissipative material, is disposed between the distal ends 722 and urges the distal ends 722 outward, which facilitates maintaining the grip by the gripping ends 712 on the electrical contact 214 (FIGURE 2). In this example, the cover 704 includes a material free slit 730, which allows the cover 704 to flex.

In one instance, the electrode connector 702 and/or the dissipative covers 704 and 708 are molded from an electrostatic discharge material. Such materials reduce static electricity and include anti- static, conductive and dissipative materials. In general, this includes a material having a surface resistance between 1 x 10³ ohms/square and 1 x 10¹² ohms per square. Conductive materials have a low electrical resistance, thus electrons flow easily across the surface or through these materials. Charges go to ground or to another conductive object that the material contacts. Dissipative materials allow the charges to flow to ground more slowly in a more controlled manner than with conductive materials. Antistatic materials are generally referred to as any material which inhibits triboelectric charging. Examples of dissipative materials include, but are not limited to, a plastic, a carbon, etc. Other dissipative materials are also contemplated herein.

FIGURE 9 schematically illustrates a variation of the shield 714 in which the slit 730 and the opening 728 are omitted. In another variation, the shield 714 comprises of a compliant material such as a flexible dissipative material. In another variation, only one of the slit 730 or the opening 728 is omitted. In another variation, the shield 714 includes two or more slits and/or another type of material free region. In yet another variation, the slit 730 and opening 728 are covered with another material providing visual access such as a visibly transparent material.

In another variation, the proximal ends 724 include another fastener such as a snap instead of the gripping ends 712. The snap is configured to engage the contact 214 of the electrode 206-210 and 618. For example, the contact 214 would be the male half and the snap would be the female half, and the groove 215 of the contact 214 snaps in place when pressed into the female half. Generally, the proximal ends 724 includes a mechanism configured to removeably interlock with the contact 214.

FIGURES 10-12 schematically illustrates cross sectional view of the electrode connector 702, electrode cover 704, and an electrode 618.

FIGURE 10 shows a cross-sectional view along line B-B of FIGURE 7. In this example, an electrical insulator 1002 is disposed between the gripping ends 712 and the dissipative cover 704. A diameter or cross section length of the shield 714 and a diameter or cross section length of the support 216 are approximately equal. In this example, there is a one-to-one correspondence between a geometry of the electrode 618 and a geometry of the cover 704. Charge on the electrode 618 is removed by the electro-static dissipative cover 704.

FIGURES 11 and 12 show variations of the electro-static dissipative cover 704 of FIGURE 10. In FIGURE 11, the diameter or cross section length of the shield 714 is less than the diameter or cross section length of the support 216. In FIGURE 12, the diameter or cross section length of the shield 714 is greater than the diameter or cross section length of the support 216. With both configurations, charge on the electrode 618 is removed by the electro-static dissipative cover 704.

FIGURE 13 schematically illustrates an example in which the lead set 622 does not include the shield 714 and the dissipative or other material covers the electrode connector 702. In this example, the electrode connector 702 includes a snap (not visible) instead of the grippers 712, and is snapped on the contact 214 of the electrode 206. Again, although the above is described with particular application to electrocardiography, the electro-static cover can be applied to other lead sets in other applications which record bio-electrical signals such as electroencephalography,

electromyography, etc. This includes applications in which electrodes and/or lead sets may be exposed to ionizing and/or other radiation which may produce static charge, and/or other applications.

FIGURE 14 describes an exemplary method for transferring an electrical biological signal from an electrode to a monitor.

At 1402, an electrical biological signal is detected by an electrode;

At 1404, the electrical biological signal is transferred from the electrode to a lead set with of a static dissipative material such as the lead set described herein.

At 1406, the electrical biological signal is transferred from the lead set to a monitor.

At 1408, optionally, the electrical biological signal is displayed and/or processed.

The above may be implemented by way of computer readable instructions, encoded or embedded on computer readable storage medium, which, when executed by a computer processor(s), cause the processor(s) to carry out the described acts. Additionally, or alternatively, at least one of the computer readable instructions is carried by a signal, carrier wave or other transitory medium, which is not computer readable storage medium. For example, when turning on an EKG apparatus, the processor thereof results in display (via a display monitor, paper, etc.) of the electrical biological signal.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A lead set (622) for transferring an electrical biological signal from an electrode to a monitoring device, comprising:

an electrode connector (702) configured to electrically connect to an electrode (206-210; 618);

a monitor connector (710) configured to electrically connect to a monitor

(624);

a cable (623) with a first end electrically coupled to the electrode connector and a second end electrically coupled to the monitor connector; and

an electro-static dissipative cover (704 and/or 708) configured to cover at least one of the electrode connector or the cable.

2. The lead set of claim 1, wherein the electro-static dissipative cover covers only the electrode connector.

3. The lead set of claim 1, wherein the electro-static dissipative cover covers only the cable.

4. The lead set of claim 1, wherein the electro-static dissipative cover covers both the cable and the electrode connector.

5. The lead set of claims 2 to 4, wherein the electro-static dissipative cover is electrically coupled to at least one of a conductor of the cable or a cable shield of the cable.

6. The lead set of any of claims 1 to 4, wherein the electro-static dissipative cover has a surface resistance between 1 x 10³ and 1 x 10¹² ohms/square.

7. The lead set of any of claims 1 to 4, wherein the electro-static dissipative cover includes one of a plastic and a carbon material.

8. The lead set of any of claims 1 to 7, wherein the electro-static dissipative cover includes a shield (714) configured with a diameter equal to a diameter of a support (216) of the electrode.

9. The lead set of any of claims 1 to 7, wherein the electro-static dissipative cover includes a shield configured with a diameter greater than a diameter of a support of the electrode.

10. The lead set of any of claims 1 to 7, wherein the electro-static dissipative cover includes a shield configured with a diameter less than a diameter of a support of the electrode.

11. The lead set of any of claims 1 to 10, wherein the electrode connector includes proximal ends (724) with a gripper (712).

12. The lead set of claim 11, further comprising: an isolating material (1002) disposed between the gripper and the electro-static dissipative cover.

13. The lead set of any of claims 1 to 10, wherein the electrode connector includes proximal ends with a snap.

14. The lead set of any of claims 1 to 14, wherein the electrode connector is configured to connect to one of an electrocardiography, electroencephalography, and electromyography electrode.

15. A method, comprising :

sensing an electrical biological signal from an electrode with a lead set that includes an electrode connector, a cable, a monitor connector, and an electro-static dissipative configured to cover at least one of the electrode connector or the cable; and

outputting the sensed electrical biological signal.

16. The method of claim 15, wherein the electro-static dissipative cover covers only the electrode connector.

17. The method of claim 15, wherein the electro-static dissipative cover covers only the cable.

18. The method of claim 15, wherein the electro-static dissipative cover covers both the electrode connector and cable.

19. The method of any of claims 15 to 18, wherein the electro-static dissipative cover has a surface resistance between 1 x 10³ and 1 x 10¹² ohms/square.

20. A computer readable storage medium encoded with computer readable instructions, which, when executed by a processer, cause the processor to:

sense an electrical biological signal from an electrode with a lead set that includes an electrode connector, a cable, a monitor connector, and an electro-static dissipative configured to cover at least one of the electrode connector or the cable;

process the sensed electrical biological signal; and

output the processed electrical biological signal.