Fast NMR cardiac profile imaging
First Claim
1. A method for providing a nuclear-magnetic-resonance (NMR) image of movement of a selected portion of a sample, relative to a predetermined center location at the origin of a set of axes defining an imaging volume, comprising the steps of:
- (a) immersing the sample in a static magnetic field formed in the imaging volume;
(b) exciting spin magnetization of nuclei in a region of the sample defined by a relatively narrow elongated probe beam;
(c) moving the probe beam to extend through the selected sample portion;
(d) acquiring a NMR response signal from the excited region, in the presence of a readout magnetic field gradient oriented along the probe beam and with a magnitude establishing the location of the selected portion therealong; and
(e) displaying said acquired NMR response signal as a profile of the sample along the beam versus time.
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Accused Products
Abstract
A substantially continuous image, recording motion of a portion of a sample, is provided by first NMR exciting, through use of a rotating-gradient (ρ) pulse signal, a relatively narrow cylindrical region, typically with diameter less than 1 inch, of magnetization intersecting the sample to be imaged and then acquiring the NMR response signal thus excited, in the presence of a readout gradient oriented along the length of the cylindrical excitation beam and establishing position thereon. A Fourier transformation of the acquired data allows display of a real-time record of the profile of the sample along the axis of the cylindrical probe beam. The cylinder-beam axis can be oriented in an arbitrary direction by proper mixing of the excitation and readout gradient fields; use of three orthogonal gradients in a Cartesian coordinate system is presently preferred. Spatial offsetting of the cylindrical beam, from the center of the static magnetic field of the NMR imaging system, to any specific location within the system'"'"'s imaging volume, can be obtained by frequency modulation of the ρ pulse RF waveform.
28 Citations
14 Claims
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1. A method for providing a nuclear-magnetic-resonance (NMR) image of movement of a selected portion of a sample, relative to a predetermined center location at the origin of a set of axes defining an imaging volume, comprising the steps of:
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(a) immersing the sample in a static magnetic field formed in the imaging volume; (b) exciting spin magnetization of nuclei in a region of the sample defined by a relatively narrow elongated probe beam; (c) moving the probe beam to extend through the selected sample portion; (d) acquiring a NMR response signal from the excited region, in the presence of a readout magnetic field gradient oriented along the probe beam and with a magnitude establishing the location of the selected portion therealong; and (e) displaying said acquired NMR response signal as a profile of the sample along the beam versus time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification