AUTOMATED NON-MAGNETIC MEDICAL MONITOR USING PIEZOELECTRIC CERAMIC DIAPHRAGM DEVICES

• US 20100331667A1
• Filed: 02/02/2009
• Published: 12/30/2010
• Est. Priority Date: 02/28/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Nelson, Mark
• Granted Patent: US 9,585,574 B2
• Time in Patent Office: Days
• US Class Current: 600/411
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: G01R 33/288 Provisions within MR facilities for enhancing safety during MR, e.g. reduction of the specific absorption rate [SAR], detection of ferromagnetic objects in the scanner room

Abstract

In magnetic resonance imaging (MRI), the powerful magnetic fields can interfere with, damage, cause premature failure in, and attract certain non-MR safe instruments. Electromagnetic ally sensitive components are eliminated in favor of MR safe components, such as ceramic piezoelectric components and bi-metallic components. Instruments that previously had to be kept a safe distance away from the main magnet (12), e.g., beyond the 5 Gauss line, while a patient was being scanned are now allowed near the patient without fear of damage to the instrument (40) or danger to the patient and medical staff or the MRI device (10).

Claims

1. A magnetic resonance system comprising:

a main magnet for generating a substantially uniform main magnetic field in an examination region;

a gradient coil assembly for imposing gradient magnetic fields on the main magnetic field in the examination region, spatially encoding the main magnetic field;

a radio frequency assembly for inducing magnetic resonance in selected dipoles of a subject in the examination region, and receiving the magnetic resonance;

an automated non-magnetic monitor disposed at least partially in the examination region to measure and display at least one physiological parameter of the subject.

2. The magnetic resonance system as set forth in claim 1, wherein the monitor includes a pump disposed in the examination region.

3. The magnetic resonance system as set forth in claim 2, wherein the pump includes a piezoelectric ceramic peristaltic pump.

4. The magnetic resonance system as set forth in claim 1, further including:

a high voltage driver for the piezoelectric pump disposed in the examination region.

5. The magnetic resonance system as set forth in claim 1, wherein the monitor includes at least one valve disposed in the examination region.

6. The magnetic resonance system as set forth in claim 5, wherein the at least one valve includes a piezoelectric ceramic diaphragm valve.

7. The magnetic resonance system as set forth in claim 6, wherein further including:

a high voltage driver for the piezoelectric diaphragm valve.

8. The magnetic resonance system as set forth in claim 1, wherein the non-magnetic monitor includes one of a blood pressure monitor and a gas analysis monitor.

9. The magnetic resonance system as set forth in claim 8, wherein the monitor includes a blood pressure monitor, the blood pressure monitor further including:

a pump disposed in the examination region;

at least one valve disposed in the examination region;

a controller for controlling high voltage drivers for driving the pump and the valve;

a memory for storing at least blood pressure readings and a time at which they were taken

an electromagnetically compatible enclosure around the controller and the memory to shield from radiate emissions.

10. The magnetic resonance system as set forth in claim 1, wherein the monitor further includes:

at least one of a bimetallic element operated valve or pump.

11. The magnetic resonance system as set forth in claim 1, wherein the main magnet generates a magnetic field of at least 2500 Gauss (0.25 T) in the examination region.

12. An MRI safe blood pressure monitor, comprising:

a pressure cuff for applying pressure to an artery of a patient;

a first transducer for sensing audible events within the artery under pressure;

a piezoelectric ceramic peristaltic pump that pressurizes the pressure cuff;

a first high voltage driver that drives the piezoelectric pump;

a second transducer that senses the pressure applied to the pressure cuff;

a first piezoelectric ceramic diaphragm valve that releases pressure from the pressure cuff at a controlled, linear rate;

a second high voltage driver that drives the first piezoelectric diaphragm valve;

pneumatic connections that connect at least the pump and the pressure cuff;

control circuitry that controls at least the pump and the diaphragm valve;

a power supply that powers at least the first and second high voltage drivers and the control circuitry.

13. The MRI safe blood pressure monitor as set forth in claim 12, further including:

an electromagnetic interference enclosure around at least the piezoelectric pump and valve, the enclosure shielding against radiate emissions.

14. The MRI safe blood pressure monitor as set forth in claim 12, wherein the first piezoelectric valve is a linear release valve.

15. The MRI safe blood pressure monitor as set forth in claim 14, further including:

a second piezoelectric diaphragm valve that acts as a dump valve for releasing pressure from the monitor; and

a third high voltage driver for driving the second piezoelectric diaphragm valve.

16. The MRI safe blood pressure monitor as set forth in claim 15, wherein both valves are bi-metallic-actuated devices.

17. A magnetic resonance system comprising:

a main magnet that generates a main magnetic field through an examination region;

a blood pressure monitor as set forth in claim 12 disposed in the examination region.

18. A method of monitoring a subject in a magnetic field comprising:

generating a main magnetic field with a main magnet of a magnetic resonance imaging device;

applying gradient magnetic fields to the examination region with a gradient coil system;

applying RF pulses to the examination region with an RF assembly;

controlling at least one valve and at least one pump located in the main magnetic field to one of;

inflate and deflate a blood pressure cuff and provide metered samples of exhaled gases to an exhaust gas analyzer.

19. The method as set forth in claim 18, further including:

inflating a pressure cuff located in the main magnetic field by closing a first, linear piezoelectric ceramic diaphragm valve, closing a second, piezoelectric ceramic diaphragm dump valve, and actuating a piezoelectric ceramic pump;

reading a pressure by releasing air from the pressure cuff by opening the first valve and turning the pump off; and

releasing remaining air from the cuff by opening the second valve.

20. The method as set forth in claim 19 wherein the main magnetic field is greater than or equal to 5000 Gauss.

21. The method as set forth in claim 18, further including:

wirelessly transmitting the blood pressure measurement to a remote location.