Integrated system and method for MRI-safe implantable devices

• US 20060025820A1
• Filed: 07/27/2005
• Published: 02/02/2006
• Est. Priority Date: 07/27/2004
• Status: Active Grant

• Current Assignee: Cleveland Clinic Foundation
• Original Assignee: Cleveland Clinic Foundation
• Inventors: Phillips, Micheal D., Lowe, Mark Joseph
• Granted Patent: US 8,874,228 B2
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61N 1/37 Monitoring; Protecting

Abstract

An implantable system includes at least one electrode that is configured to apply a stimulus to surrounding tissue based on a control signal. A control module provides the control signal, such as for controlling application of the stimulus, which can be an electrical stimulus, a chemical stimulus or a combination thereof. A detector is configured to detect a temperature characteristic associated with one or more of the electrode and the surrounding tissue. An output signal is provided based on the detected temperature characteristic. The output signal can be used by an associated diagnostic system to terminate a diagnostic procedure, such as to mitigate heating of the electrode and/or the surrounding tissue.

Claims

1. An implantable system, comprising:

at least one electrode configured to apply a stimulus to surrounding tissue based on a control signal;

a control module that provides the control signal; and

a detector configured to detect a temperature characteristic associated with at least one of the at least one electrode and the surrounding tissue, an output signal being provided based on the detected temperature characteristic.

2. The implantable system of claim 1, wherein the detector is part of the control module, the control module further comprising:

a signal generator that provides the control signal as an electrical signal;

a control system configured to control the signal generator to provide the electrical signal, the control system providing the output signal in response to determining that the detected temperature characteristic exceeds a temperature threshold.

3. The implantable system of claim 2, further comprising a battery integrated into the control module for providing power.

4. The implantable system of claim 2, further comprising an interface configured to communicatively couple the control module with a communications link, such that the output signal can be communicated from the control module via the communications link.

5. The implantable system of claim 4 in combination with a diagnostic system, the combination comprising the control module connected with the diagnostic system via the communications link, the diagnostic system terminating at least selected operation in response to the output signal indicating that temperature characteristic exceeds the temperature threshold.

6. The combination of claim 5, wherein the diagnostic system comprises a magnetic resonance imaging (MRI) system, the MRI system further comprising a control system that terminates an imaging sequence in response to the output signal.

7. The implantable system of claim 1, wherein the temperature threshold is programmable.

8. The implantable system of claim 1, further comprising:

a lead system that includes the at least one electrode operatively connected to an elongate body portion; and

an extension that electrically connects the at least one electrode of the lead system with the control module.

9. The implantable system of claim 8, further comprising a transducer operatively connected with the lead system, the transducer being communicatively coupled with the control module for providing a temperature signal that varies as a function of temperature of at least one of the lead system, the at least one electrode and the surrounding tissue, the control module providing the output signal based on the temperature signal.

10. The implantable system of claim 9, wherein the transducer is located adjacent a distal end of the of the elongate body portion.

11. The implantable system of claim 9, wherein the at least one transducer comprises a thermocouple.

12. The implantable system of claim 8, wherein the at least one transducer comprises a length of an electrically conductive wire that extends longitudinally along an exterior of the elongate body portion of the lead system.

13. The implantable system of claim 1, wherein the detector further comprises:

a comparator that provides a first comparator signal based on comparison of an average indication of detected temperature associated with at least one of the at least one electrode and the surrounding tissue relative to a predetermined temperature threshold; and

output circuitry that provides the output signal based on the first comparator signal.

14. The implantable system of claim 13, wherein the detector further comprises a second comparator that provides a second comparator signal based on a comparison of a rate of change in temperature associated with at least one of the at least one electrode and the surrounding tissue relative to a predetermined temperature threshold, the output circuitry provides the output signal based on at least one of the first comparator signal and the second comparator signal.

15. An implantable system, comprising:

a lead system comprising a body portion and at least one electrode attached to the body portion;

a transducer operably connected with the lead system, the transducer being operative to provide a transducer signal that varies as a function of a temperature characteristic associated with at least one of the lead system, the at least one electrode and surrounding tissue;

an integrated module communicatively connected with the lead system via an extension, the module comprising;

a signal generator that provides at least one electrical signal to the at least one electrode via the extension; and

a detector configured to provide a detector signal indicative of the temperature characteristic based on the transducer signal.

16. The implantable apparatus of claim 15, further comprising a control system configured to control the signal generator to provide the at least one electrical signal, the control system also providing an output signal in response to determining that the temperature characteristic exceeds a temperature threshold based on the detector signal.

17. The implantable apparatus of claim 16, wherein the temperature threshold is programmable.

18. The implantable apparatus of claim 15, further comprising an interface configured to communicatively couple the integrated module with a diagnostic system via a communications link, the diagnostic system terminating at least application of radiofrequency pulses in response to a signal received via the communications link indicating that the temperature characteristic exceeds a temperature threshold.

19. The implantable apparatus of claim 15, wherein the transducer comprises a thermocouple located adjacent a distal end of the of the body portion.

20. The implantable apparatus of claim 15, wherein the at least one transducer comprises a length of an electrically conductive wire that extends longitudinally along the body portion of the lead system.

21. The implantable apparatus of claim 15, wherein the detector further comprises:

a comparator that provides a first comparator signal based on comparison of the indication of a temperature characteristic relative to a predetermined threshold;

a second comparator that provides a second comparator signal based on comparison of a rate of change in temperature associated with at least one of the at least one electrode and the surrounding tissue relative to a predetermined temperature threshold, the rate of change in temperature being determined as a function of the indication of a temperature characteristic provided by the detector; and

the integrated module providing an output signal based on at least one of the first comparator signal and the second comparator signal.

22. A system for mitigating risk of injury during diagnostic imaging, the system comprising:

an implantable system comprising;

at least one device configured for delivering stimulus to surrounding tissue in a patients body;

a control module that controls the delivery of stimulus by the at least one device, the control module being configured to provide an output signal based on a temperature characteristic associated with at least one of the at least one device and the surrounding tissue;

an interface configured to communicatively couple the control module with a diagnostic system via a communications link;

the diagnostic system configured to apply at least one magnetic field, the diagnostic system being configured to terminate the at least one magnetic field in response to the output signal indicating that the temperature characteristic exceeds a threshold.

23. The system of claim 22, wherein the diagnostic system comprises a magnetic resonance imaging (MRI) system, the MRI system further comprising a control system that causes application of at least the radiofrequency pulses to be terminated in response to the output signal.

24. The system of claim 22, wherein the at least one device of the implantable system comprises:

an elongate body portion;

at least one electrode operative connected with the elongate body portion, the at least one electrode providing electrical stimulus to the surrounding tissue based on a control signal from the control module.

25. The system of claim 24, further comprising a transducer operatively connected with the elongate body portion, the transducer providing a transducer signal to the control module that varies as a function of temperature of at least one of the elongate body portion, the at least one electrode and the surrounding tissue, the control module providing the output signal based on the transducer signal.

26. The system of claim 25, wherein the transducer is located adjacent a distal end of the of the elongate body portion.

27. The system of claim 22, further comprising at least one thermocouple that provides a signal indicative of temperature of at least one of the at least one device and the surrounding tissue, the control module providing the output signal based on the signal provided by the thermocouple.

28. The system of claim 22, further comprising a length of an electrically conductive wire that extends longitudinally along an exterior of the at least one device, the control module providing the output signal based on an indication of temperature associated with at least one of the at least one device and the surrounding tissue that varies according to an electrical characteristic of a signal applied by the control module to the wire.

29. The system of claim 22, wherein the communications link comprises one of an electrically conductive link, a wireless link and an optical link.

30. The system of claim 22, wherein the at least one magnetic field comprises at least one of a gradient magnetic field or a varying electromagnetic field.