Quadrature coil for neurovascular imaging and spectroscopy of the human anatomy

A method of performing quadrature NMR imaging on a subject, comprising the steps of:

• providing an NMR coil system including a continuous conductor having first and second vertical mode conductor loops each having first and second ends and including first and second horizontal mode conductor elements each having first and second ends;
• joining the first ends of said first and second horizontal mode conductor elements to respective horizontal mode feedpoints;
• joining the second ends of said first and second horizontal mode conductor elements to electrical midpoints of said respective vertical mode conductor loops;
• during a vertical mode of operation, transmitting a first electromagnetic waveform having a predetermined magnitude and phase to the first ends of said vertical mode conductor loops in a manner balanced to common ground;
• responsive to said steps of transmitting said first and second electromagnetic waveforms, forming voltage nulls at said midpoints;
• during a horizontal mode of operation, transmitting a second electromagnetic waveform having a second predetermined magnitude and phase to the first ends of the horizontal mode conductor elements in a balanced manner with respect to common ground;
• and
• responsive to said steps of transmitting said third electromagnetic waveform, forming voltage nulls at said first ends of said vertical mode conductor loops.

A nuclear magnetic resonance quadrature coil operable in both vertical and horizontal modes and permitting enhanced access to a patient, the quadrature coil comprising:

• a shell having first and second ends, and top and bottom halves disposed between said first and second ends, said shell encasing a volume of a portion of the patient's anatomy, wherein each half includes left and right quarters;
• a continuous conductor including
• a vertical mode coil having conductor elements disposed respectively on said top left quarter, said top right quarter, said bottom right quarter and said bottom left quarter, each conductor element extending from said first end to said second end of said shell, and vertical mode feedpoints respectively connected to each of said conductor elements at said first end;
• and
• a horizontal mode coil having a top conductor element disposed on said top half of said shell and a bottom conductor element disposed on said bottom half of said shell, said top and bottom conductor elements extending from said first end to said second end of said shell, and horizontal feedpoints connected to the last said top and bottom conductor elements at said first end;
• wherein
• said top conductor element of said horizontal mode coil and said top left and top right conductor elements of said vertical mode coil are joined at said second end, and said bottom conductor element of said horizontal mode coil and said bottom left and bottom right conductor elements of said vertical mode coil are joined at said second end.

A hinged quadrature coil for magnetic resonance imaging and spectroscopy, comprising:

• a continuous conductor including a top coil formation and a bottom coil formation each having first and second ends, said first end of said top coil formation hinged to said first end of said bottom coil formation and said coil formations operable between closed and open positions with respect to each other, said top and bottom coil formations disposed around a longitudinal axis when said top and bottom coil formations are in said closed position;
• each of said coil formations further comprising a conductor loop having a first and second end, said conductor loop first ends being disposed near the hinged end of each of said coil formations, said conductor loop extending from said first end to said second end of its respective coil formation;
• and
• feedpoints of said conductor loops of said coil formations respectively disposed at said first ends thereof.

A quadrature coil for magnetic resonance imaging and spectroscopy comprising:

• a continuous conductor including a first and a second coil formation each having a near end and a far end longitudinally opposed to said respective near end, said first and second coil formations formed around a longitudinal axis;
• each of said coil formations further comprising the following electrically connected conductor segments:
• first and second arcuate segments formed around said axis through predetermined arcs and disposed near said near end;
• first and second linear segments having first ends joined to ends of said respective first and second arcuate segments, said first and second linear segments aligned with said longitudinal axis and extending from respective ones of said first ends to respective second ends;
• first and second curved segments having first ends joined to second ends of said respective first and second linear segments;
• and
• a third linear segment disposed at said far end of said coil formation and perpendicular to said axis, opposed ends of said third linear segment connected to second ends of said respective curved segments.

A quadrature coil for magnetic resonance imaging and spectroscopy comprising:

• a continuous conductor including a pair of coil formations disposed in opposed relationship around a longitudinal axis, at least one coil formation including:
• a barrel portion including first and second linear conductor elements parallel to said axis and each disposed at respective predetermined angles from a horizontal plane including said axis;
• and
• an extension portion longitudinally extending from said barrel portion and including a conductor element disposed to be bisected by a vertical plane including said axis, and electrically coupling said first and second linear conductor elements.

A quadrature coil for nuclear magnetic resonance imaging, comprising:

• a shell formed about a longitudinal axis for supporting a continuous conductor, and said shell having first and second opposed ends, said second end being open and said shell dimensioned so as to permit the introduction of an imaging subject along said longitudinal axis;
• said continuous conductor including
• a first pair of vertical mode conductor elements disposed on said shell and extending from said first end of said shell to said second end, said conductor elements formed to be bilaterally symmetrical about a vertical plane including said axis, said conductor elements joined near said second end of said shell at a first electrical midpoint;
• a second pair of vertical mode conductor elements disposed on said shell and extending from said first end to said second end, said second pair of vertical mode conductor elements formed to be bilaterally symmetrical about said vertical plane, each of said second pair of vertical mode conductor elements coupled to a respective one of said first pair of vertical mode conductor elements at said first end of said shell, said second pair of vertical mode conductor elements joined to each other at said second end at a second electrical midpoint;
• a first horizontal mode conductor element disposed on said shell substantially within said vertical plane and extending from said first end to said second end, said first horizontal mode conductor element joined to said first pair of vertical mode conductor elements at said first electrical midpoint;
• and
• a second horizontal mode conductor element disposed on said shell substantially within said vertical plane and extending from said first end to said second end, said second horizontal mode conductor element joined to said second pair of vertical mode conductor elements at said second electrical midpoint, a horizontal feedpoint at said first end joining said first and second horizontal conductor elements.

A quadrature coil NMR system, comprising:

• a continuous conductor including
• first and second vertical mode loops each having a first end, a second end and an electrical midpoint, said first ends of said first and second loops joined together at a first vertical mode feedpoint, said second ends of said first and second loops joined together at a second vertical mode feedpoint;
• and
• first and second horizontal mode conductor elements each having a first end and a second end, said first ends of said horizontal mode conductor elements joined to respective horizontal mode feedpoints, said second ends of said horizontal mode conductor elements joined to respective midpoints of the vertical mode loops;
• a receiver coupled to said vertical mode feedpoints and operable, during a vertical mode of operation, to receive a vertical mode electromagnetic signal having a first predetermined magnitude and phase at said vertical mode feedpoints, the voltages at the feedpoints being of equal amplitudes and opposite phases with respect to common ground, such that said midpoints experience voltage nulls;
• said receiver coupled to said horizontal mode feedpoints and operable, during a horizontal mode of operation, to receive a horizontal mode electromagnetic signal having a second predetermined magnitude and phase at said horizontal mode feedpoints, the voltages at the feedpoints being of equal amplitudes and opposite phases with respect to common ground, such that said vertical mode feedpoints are electrical midpoints which experience voltage nulls during said horizontal mode of operation of said system;
• and
• a means to combine said vertical and horizontal mode signals constructively to achieve quadrature operation.

A quadrature coil capable of transmitting and receiving electromagnetic signals for imaging a portion of a patient's anatomy, said quadrature coil comprising:

• a continuous conductor including
• first and second vertical mode loops each having an electrical midpoint;
• a first horizontal mode conductor element having an end joined to the electrical midpoint of the first vertical mode loop;
• and
• a second horizontal mode conductor element having an end joined to the electrical midpoint of the second vertical mode loop;
• and
• means for permitting access of at least a portion of the patient into the continuous conductor.