POSITION SENSOR FOR MRT DETECTION

• US 20110148400A1
• Filed: 12/18/2010
• Published: 06/23/2011
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: Biotronik SE & Company KG
• Original Assignee: Biotronik CRM Patent AG (Biotronik SE & Company KG)
• Inventors: Doerr, Thomas, Weiss, Ingo
• Granted Patent: US 8,768,430 B2
• Time in Patent Office: Days
• US Class Current: 324/207.11
• CPC Class Codes: A61B 2560/029 adapted for auto-initiation
• CPC Class Codes: A61B 5/065 Determining position of the probe employing exclusively positioning means located on or in the probe, e.g. using position sensors arranged on the probe
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: G01R 33/285 Invasive instruments, e.g. catheters or biopsy needles, specially adapted for tracking, guiding or visualization by NMR

Abstract

Allows the specificity of an automatic MRT detection to be increased in a simple manner. This is achieved using an automatically calibrating position sensor, so that the user does not have to perform additional calibration of this sensor. Incorrect sensor calibrations are thus eliminated as well.

Claims

1. An implantable medical device comprising:

a unit configured to detect magnetic resonance imaging interference fields, comprising

at least one sensor and/or indicator for electromagnetic interference fields typical for magnetic resonance imaging or magnetic fields typical for magnetic resonance imaging;

at least one control unit coupled to the unit configured to detect magnetic resonance imaging interference fields comprising

at least one diagnostic unit and/or

at least one treatment unit;

wherein the unit is configured to detect magnetic resonance imaging interference fields further comprises a position sensor; and

,

wherein the unit is further configured to detect magnetic resonance imaging interference fields is configured to

detect interference from magnetic resonance imaging interference fields only when, in addition to at least one sensor and/or at least one indicator for electromagnetic interference fields typical for magnetic resonance imaging, the position sensor indicates a prone posture of a patient associated with said implantable medical device.

2. The implantable medical device according to claim 1, wherein the position sensor is self-calibrating, wherein the prone posture is automatically detected, and/or the calibration is triggered via an external device, such as a patient device and/or programming device, and/or the prone posture is verified via an external device, such as a patient device and/or programming device.

3. The implantable medical device according to claim 2, wherein the calibration of the position sensor is carried out after evaluation of a time of day.

4. The implantable medical device according to claim 1, wherein for identification of the prone posture, diurnal phases with minimum heart rate are evaluated.

5. The implantable medical device according to claim 1, wherein the at least one control unit is configured to identify night sleep by an evaluation of a heart rate variability and a circadian rhythm thereof

6. The implantable medical device according to claim 1, wherein the at least one control unit is configured to identify night sleep by an evaluation of a respiratory rate.

7. The implantable medical device according to claim 1, wherein the at least one control unit is configured to identify night sleep by an evaluation of patient activity.

8. The implantable medical device according to claim 1, wherein the at least one control unit is configured to identify night sleep by an evaluation at least one EEG parameter.

9. The implantable medical device according to claim 1, wherein detection of magnetic resonance imaging interference fields initiates a predeterminable reaction of the implantable medical device only within a predeterminable time window.

10. The implantable medical device according to claim 1, wherein the unit configured to detect magnetic resonance imaging interference fields includes at least one of the following sensors and/or indicators:

GMR sensor,

MagFET sensor,

Hall sensor,

electro-optical converter,

battery voltage sensor configured to monitor voltage during capacitor charging,

RF field detector,

magnetic gradient field detector,

current detector for currents induced by electromagnetic fields,

11. The implantable medical device according to claim 1, wherein upon identification of electromagnetic interference fields by the unit configured to detect magnetic resonance imaging interference fields, the at least one control unit is configured to:

change to an magnetic resonance imaging-safe state,

remain for a prolonged period of time in the magnetic resonance imaging-safe state or a state that is insensitive to electromagnetic interference fields.

emit electromagnetic pulses to signal that the implantable medical device is present in an electromagnetic field, and transmit information as well as an interference and display said interference on a screen of a magnetic resonance imaging device, and

allow administration of treatment and/or detection of electrical states of tissue only in time windows in which no electromagnetic interference fields are detected and/or carry out a reconstruction of a measurement for the regions in which the detection is not allowed on account of detected electromagnetic interference fields.

12. A method comprising:

increasing the specificity in the detection of magnetic resonance imaging interference fields with an implantable medical device comprising;

a unit configured to detect magnetic resonance imaging interference fields, comprising

at least one sensor and/or indicator for electromagnetic interference fields typical for magnetic resonance imaging or magnetic fields typical for magnetic resonance imaging;

at least one control unit coupled to the unit configured to detect magnetic resonance imaging interference fields comprising

at least one diagnostic unit and/or

at least one treatment unit;

wherein the unit is configured to detect magnetic resonance imaging interference fields further comprises a position sensor; and

,

detecting via unit is further configured to detect magnetic resonance imaging interference fields, interference from magnetic resonance imaging interference fields only when, in addition to at least one sensor and/or at least one indicator for electromagnetic interference fields typical for magnetic resonance imaging, the position sensor indicates a prone posture of a patient associated with said implantable medical device.