Gyromagnetic resonance fourier transform zeugmatography
AssigneeVarian Associates, Inc.
InventorRichard R. Ernst
Life of this patent
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Abstract
An improved technique is disclosed for forming two- or three-dimensional images of a macroscopic sample by means of gyromagnetic resonance. A train of free induction decay transient resonance signals are induced and detected from a sample in a region to be imaged. A sequence of pulsed magnetic field gradients are applied during the series of free induction decay signals to derive sets of gyromagnetic resonance data as a function of the changing magnetic field gradients. Two- or three-dimensional images are reconstructed from the sets of resonance data by two- or three-dimensional Fourier transformation.
Claims28
In a method of pulse gyromagnetic resonance zeugmatography, the steps of:
- a. inducing a transient gyromagnetic resonance signal from a sample of matter disposed in a region to be imaged by applying an RF pulse to induce a transverse magnetic moment of the sample;
- b. applying for a first time period a first magnetic field gradient upon the gyromagnetic sample of matter within said region after the end of said RF pulse and during the gyromagnetic resonance induced by said pulse;
- c. applying for a second time period a second magnetic field gradient relative to the said region after the end of said RF pulse and during the gyromagnetic resonance induced by said RF pulse wherein the ratio of said first time period to said second time period has a first value;
- and
- sampling, detecting and storing the induced transient gyromagnetic resonance signal after said first time period.
In an apparatus for gyromagnetic resonance zeugmatography:
- pulse means for inducing a train of transient gyromagnetic resonance signals from a sample of matter disposed in a region to be imaged;
- means for applying a magnetic field gradient upon the gyromagnetic sample of matter within said region during the induced resonance of the sample of matter;
- means for rapidly changing the orientation of the magnetic field gradient relative to the region during said resonance signals of said train of induced resonances of the sample of matter;
- and
- means for detecting the induced train of transient gyromagnetic resonance signals as a function of the duration of the different orientations of the magnetic field gradient in the region to derive gyromagnetic resonance data from which to derive an image of said region.
In a method of gyromagnetic resonance zeugmatography, the steps of:
- repetitively inducing a transient gyromagnetic resonance signal from a sample of matter disposed in a region to be imaged;
- applying for a first period of time a first magnetic field gradient upon the gyromagnetic sample of matter within said region after inducing each said transient gyromagnetic resonance signal;
- applying for a second period of time a second magnetic field gradient relative to the said region after applying said first magnetic field gradient;
- and
- sampling, detecting, and storing said transient gyromagnetic resonance signals for a plurality of different ratios of said first period of time to said second period of time and analyzing said stored transient gyromagnetic resonance signals as a function of the different ratios of the time of application of said first and second magnetic field gradients in the region to derive gyromagnetic resonance data representative of an image of said region.
Dependencies are inferred from the claim text.