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US 5,296,808 AGranted
MRI imaging system without aliasing
OwnerAlbert Macovskiinventor
Life of this patent
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Abstract
A high frequency oscillatory signal is added to the gradient waveform to provide a blurring or convolution prior to sampling. The received signal can be modulated to provide the desired space-limiting function and thus avoid aliasing. The received signal is filtered prior to sampling to remove these high frequency signals.
Claims9
In a method for imaging precessing magnetic moments of an object within a volume using magnetic resonance imaging the steps of:
- scanning k-space of the object using a sequence of magnetic gradient waveforms in at least two spatially orthogonal axes;
- applying a first periodic waveform to at least one magnetic gradient axis which is superimposed on the gradient waveforms providing the k-space scan to provide a convolution operation which will substantially prevent aliasing of the image of the object;
- receiving signals produced by the precessing magnetic moments in the object at each point of the k-space scan;
- low-pass filtering the received signals at a cutoff frequency lower than the frequency of the periodic gradient waveform;
- sampling the received signal;
- and
- transforming the samples into an image of the object.
4 more elements
Apparatus for imaging precessing magnetic moments of an object within a volume using magnetic resonance imaging comprising:
- means for scanning k-space of the object using a sequence of magnetic gradient waveforms in at least two spatially orthogonal axes;
- means for applying a first periodic waveform to at least one magnetic gradient axis which is superimposed on the gradient waveforms providing the k-space scan to provide a convolution operation which will substantially prevent aliasing of the image of the object;
- means for receiving signals produced by the precessing magnetic moments in the object at each point of the k-space scan;
- means for low-pass filtering the received signals at a frequency lower than the frequency of the periodic gradient waveform;
- means for sampling the received signal;
- and means for transforming the samples into an image of the object.
3 more elements
Dependencies are inferred from the claim text.