Method for Non-Invasive Measurement of Cardiac Output

• US 20110172518A1
• Filed: 01/10/2010
• Published: 07/14/2011
• Est. Priority Date: 05/01/2003
• Status: Active Grant

• Current Assignee: Aspect Imaging Ltd.
• Original Assignee: Aspect Imaging Ltd.
• Inventors: Rapoport, Uri
• Granted Patent: US 8,798,715 B2
• Time in Patent Office: Days
• US Class Current: 600/422
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/0263 using NMR
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: G01R 33/36 Electrical details, e.g. matching or coupling of the coil to the receiver
• CPC Class Codes: G01R 33/383 using permanent magnets
• CPC Class Codes: G01R 33/3873 using ferromagnetic bodies ; Passive shimming
• CPC Class Codes: G01R 33/48 NMR imaging systems
• CPC Class Codes: G01R 33/5635 Angiography, e.g. contrast-enhanced angiography [CE-MRA] or time-of-flight angiography [TOF-MRA]

Abstract

A comparatively light and compact permanent magnet arrangement for an MRI apparatus has a pair of opposed permanent magnet arrays with a shimming system to adjust the uniformity and strength of a magnetic field in a central chamber of the apparatus. The MRI apparatus is used to examine the extremities of a patient to determine cardiovascular characteristics from an analysis of the blood flow through selected arteries in the extremity. The information collected can be used to calculate such characteristics as total cardiac output, blood flow, arterial wall thickness and elasticity and the presence of plaque.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. (canceled)

13. (canceled)

14. (canceled)

15. (canceled)

16. (canceled)

17. (canceled)

18. (canceled)

19. A method for non-invasively performing an examination to determine selected physical characteristics of the heart and cardiovascular system of a living subject, said method comprising the steps of:

selecting an extremity of the subject suitable for conducting said examination;

providing an apparatus adapted to conduct MRI analysis of selected blood vessels within said extremity, said MRI apparatus of the type having a housing, first and second opposed permanent magnet arrangements defining an air gap therebetween, an access port in said housing to enable the placement of said extremity within said air gap, and means to create a magnetic field across said air gap with sufficient field strength, uniformity and resolution to perform said examination;

providing an array of RF coils to pulse and detect electromagnetic signals within said air gap;

pulsing selected of said RF coils and detecting the signals produced thereby;

creating an MRI image of said selected blood vessels at selected time intervals to produce information as to selected of said cardiovascular system characteristics; and

collecting and analyzing said information.

20. The method as recited in claim 19 including the step of selelcting said cardiovascular characteristic to be the cross-sectional area of a selected blood vessel measured at selected times during the beating of said heart.

21. The method as recited in claim 19 including the step of selelcting said cardiovascular characteristic to be the flow rate of blood through a selected blood vessel measured at selected times during the beating of said heart.

22. The method as recited in claim 19 including the step of selecting said cardiovascular characteristic to be the total cardiac output of said heart.

23. The method as recited in claim 19 including the step of selecting said cardiovascular characteristic to be the wall thickness of a selected blood vessel.

24. The method as recited in claim 19 including the step of selecting said cardiovascular characteristic to be the elasticity of a selected blood vessel.

25. The method as recited in claim 19 including the step of selecting said cardiovascular characteristic to be the flow mediated dilation of a selected blood vessel.

26. The method as recited in claim 19 including the step of selecting said cardiovascular characteristic to be the presence, type and thickness of plaque in a selected blood vessel.

27. The method as recited in claim 19 including the step of selecting said cardiovascular characteristic to be the wall thickness of a selected blood vessel.

28. The method as recited in claim 22 including the steps of selecting said extremity to be a human arm and selecting said blood vessels to be the radial and ulnar arteries in said arm, and

calculating total cardiac output by determining the volume of blood per unit time flowing through said arteries and comparing said blood volume to tables of known relationships of total cardiac output to blood flow measured through said arteries.

29. The method as recited in claim 19 including the step of pulsing said coils when said heart beats.

30. The method as recited in claim 19 including the step of performing a first said examination for selected of said physical characteristics and storing the results of each said examination for use as a base line to determine subsequent changes in said characteristics.