Intraluminal Magneto Sensor System and Method of Use

• US 20090322323A1
• Filed: 05/11/2006
• Published: 12/31/2009
• Est. Priority Date: 05/11/2005
• Status: Active Grant

• Current Assignee: University of Houston System, Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: University of Houston System, Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Cherukuri, Paul, Naghavi, Morteza, Wosik, Jaroslaw, Brazdeikis, Audrius
• Granted Patent: US 8,212,554 B2
• Time in Patent Office: Days
• US Class Current: 324/244
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: G01R 33/02 Measuring direction or magnitude of magnetic fields or magnetic flux G01R33/20 takes precedence

Abstract

A system (100) including a catheter mounted magneto sensor (114), such as a superconducting quantum interference device (SQUID), and methods using the system are disclosed, where the system and method are designed to detect changes in a magnetic field in a body of interest, such as a patient, to detect changes in a magnetic field in a patient, to identify loci in a target body that accumulate magnetic particles or to identify vulnerable plague in a patient.

Claims

1. An intraluminal magneto sensor system comprising:

a catheter; and

a magneto sensor attached to a distal end of the catheter.

2. The system of claim 1, wherein the magneto sensor is selected from the group consisting of a SQUID sensor, a magneto-optical sensor, a flux-gate magnetometer, a flux transformer, a Hall-effect sensor, a cantilever-based sensor, a magneto-resistive sensor, a magneto-inductive sensor, a magneto-resonance sensor and a combination thereof.

3. The system of claim 1, wherein the magneto sensor system comprises a magnetizing unit, where the unit is attached to the catheter or external to the catheter.

6. The system of claim 3, wherein the magnetizing unit is selected from the group consisting of an electromagnetic coil, electromagnet and permanent magnet.

7. The system of claim 1, wherein the magneto sensor system comprises a flux concentrator.

8. The system of claim 7, wherein the flux concentrator unit is selected from the group consisting of an ferromagnetic, metamaterial-based flux concentrator, and superconducting flux concentrator.

9. The system of claim 1, further comprising a sensor cable including a first end connected to the sensor, where the cable extends through the catheter.

10. The system of claim 1, further comprising a cryogenic fluid and wherein magneto sensor is a cryogenic sensor and the catheter is thermally insulated.

11. The system of claim 10, wherein the cryogenic fluid is a gas and wherein the magnetic sensor is a SQUID sensor.

12. The system of claim 10, further comprising a means for circulating the cryogenic fluid.

16. The system of claim 1, wherein the magneto sensor comprises:

a sensing element attached to the catheter; and

a detector operatively connected to the sensing element.

17. The system of claim 16, wherein the detector is not located adjacent to the sensing element and the sensing element is a pick up coil or a gradiometer.

20. The system of claim 1, further comprising an auxiliary sensor selected from the group consisting of a temperature sensor, a pH sensor, a pressured, a chemical sensor, an ion specific electrode sensor, and a combination thereof.

32. The method claim 30, wherein the sensor is moveable and the method further comprising the step of:

moving the magneto sensor to a different AOI of the animal;

repeating steps of claim 1 and the moving step, and

determining loci within the AOI that have an amount of the magnetic substance above a threshold value.

4. (canceled)

5. (canceled)

13. (canceled)

14. (canceled)

15. (canceled)

18. (canceled)

19. (canceled)

21. (canceled)

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)

28. (canceled)

29. (canceled)

30. A method for identifying loci in an animal that accumulate magnetic substance comprising the steps of:

inserting an intraluminal magneto sensor system including a catheter and a magneto sensor attached to a distal end of the catheter and positioning the sensor adjacent an area of interest (AOI) of the animal,

administering a magnetic substance to the animal,

measuring a first magnetic field distribution in the animal at the AOI with the magneto sensor, and

determining an amount of the magnetic substance in the AOI of the animal from the distribution.

31. The method of claim 30, further comprising the step of:

measuring a second magnetic field distribution in the AOI with the magneto sensor, prior to the administering step,

comparing the first and second magnetic field distributions, and

determining loci within the AOI that have an amount of the magnetic substance above a threshold value.

33. A method for measuring weak magnetic field perturbations due to locally accumulation of a magnetically active agent at loci in an animal comprising the steps of:

i. inserting an intraluminal magneto sensor system including a catheter and a magneto sensor attached to a distal end of the catheter and positioning the sensor adjacent an area of interest (AOI) of the animal,

ii. monitoring cardiac activity electrically or magnetically of the animal;

iii. determining a beginning of a trigger signal interval, t_o by analyzing a cardiac cycle waveform of the animal;

iv. determining a duration, t_d of the trigger signal interval;

v. generating a trigger signal waveform using parameters determined in steps (iii) and (iv);

vi. transmitting the trigger signal waveform to an arbitrary-form signal generator in order to generate an excitation signal waveform of chosen duration at the end of trigger;

vii. transmitting the excitation signal waveform through an excitation coil setup in order to achieve a required polarization of magnetic moments of magnetic agent;

viii. repeating steps (ii) through (vii);

ix. detecting a biomagnetic signal at the magnetometer;

x. extracting data from the selected interval of the cardiac cycle that equals a length of the excitation signal waveform; and

xi. transforming the data from step (x) into a data form which indicates presence of the agent at the target location.

34. A method for measuring weak magnetic field perturbations due to locally accumulation of a magnetically active agent at loci in an animal comprising the steps of:

i. inserting an intraluminal magneto sensor system including a catheter and a magneto sensor attached to a distal end of the catheter and positioning the sensor adjacent an area of interest (AOI) of the animal,

ii. exciting the AOI with acoustic radiation energy with a dual beam ultrasonic transmitter probe adapted to generate a mechanical vibration of the agent in the AOI at a beat frequency created by an interference of the dual beam ultrasound;

iii. detecting a biomagnetic signal with the magnetometer,

iv. applying a modulation to the AOI to allow phase sensitive detection,

v. localizing loci within the AOI using the probe for data registration, and

vi. transforming the data from step (v) into a data form which indicates a presence of the agent in the loci of the AOI.