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Method for non-invasive measurement of cardiac output

  • US 8,798,715 B2
  • Filed: 01/10/2010
  • Issued: 08/05/2014
  • Est. Priority Date: 05/01/2003
  • Status: Active Grant
First Claim
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1. 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 for use in performing MRI analysis of living tissue;

    said apparatus comprising;

    a cylindrical housing formed from magnetically conductive material,said housing having a housing wall defining a space there within and having first and second open ends;

    a first permanent magnet arrangement comprising;

    a first main magnet formed as a right cylindrical solid having a central axis, an outer wall and first and second opposed faces perpendicular to said main magnet central axis;

    a first pole piece formed from ferromagnetic material, said first pole piece having a central axis and first and second opposed pole piece faces perpendicular to said first pole piece central axis, the first of said pole piece faces being positioned at and coextensive with said first main magnet first face;

    a first side magnet, said side magnet having an inner opening sized and shaped to match the outer dimensions of said first pole piece, said first side magnet positioned about the outer periphery of said first pole piece;

    providing at least a first cavity within said first pole piece, placing a first shim within said first cavity,adjusting the magnetic flux created by said first permanent magnet arrangement by altering the selected orientations and positions of said first shim within said first cavity;

    said first permanent magnet arrangement positioned within said housing proximate said first open end with said first side magnet contacting said housing wall;

    a second permanent magnet arrangement comprising;

    a second main magnet formed as a right cylindrical solid having a central axis, an outer wall and first and second opposed faces perpendicular to said second main magnet central axis;

    a second pole piece formed from ferromagnetic material, said second pole piece having a central axis and first and second opposed pole piece faces perpendicular to said second pole piece central axis, the first of said pole piece faces of the second pole piece being positioned at and coextensive with said second main magnet first face;

    a second side magnet, said second side magnet having an inner opening sized and shaped to match the outer dimensions of said second pole piece, said second side magnet positioned about the outer periphery of said second pole piece; and

    ,providing at least a first cavity within said second pole piece, placing a first shim within said first cavity, and adjusting the magnetic flux created by said second permanent magnet arrangement, by altering the selected orientations and positions of said first shim within said first cavity, said second permanent magnet arrangement positioned within said housing proximate said second open end with said second side magnet contacting said housing wall;

    said first and second permanent magnet arrangements spaced apart one from another with said second pole piece face of said first permanent magnet arrangement first pole piece facing said second pole piece face of said second permanent magnet arrangement second pole piece;

    said first and second permanent magnet arrangements and said housing wall defining there between an air gap; and

    an access port formed in said housing wall allowing said tissue to be positioned within said air gap;

    providing a first 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 selected blood vessels at selected time intervals to produce information to determine said heart and cardiovascular system characteristics; and

    collecting and analyzing said information;

    wherein said heart and cardiovascular system characteristics are determinable accurately within high strength uniform and high resolution magnetic field across a portion of the body.

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