Linear combination steady-state free precession MRI

A method of collecting image data with selective spectral suppression comprising the steps of:

• a) placing an object in a magnetic field,
• b) repeatedly applying a sequence of two or more RF excitation pulses to the object at a repetition rate, whereby a repeated sequence of two or more substantially different spectrally selective steady state magnetizations are established,
• c) applying magnetic gradients between said RF pulses,
• d) acquiring NMR signals during the time said magnetic gradients are applied,
• e) combining said signals to produce an image with selective spectral suppression.

A method of collecting image data with selective spectral suppression using steady-state free precession magnetic resonance imaging comprising the steps of:

• a) placing an object in a magnetic field,
• b) applying time varying magnetic gradients along three axes to the object,
• c) applying a plurality of RF excitation pulses to the object at a sequence repetition rate, the phase of the RF pulses being related by a fixed phase increment and the repetition rate being selected to suppress nuclei spins within a selected spectral range,
• d) obtaining multiple datasets after applying multiple RF excitation pulses,
• e) computing discrete Fourier transformed data sets for each pixel in the multiple data sets,
• f) applying complex weighting to the Fourier transformed data sets, and
• g) combining the weighted Fourier transformed data sets to produce a data set with selective spectral suppression.

Magnetic resonance imaging apparatus for collecting image data with selective spectral suppression using steady-state free precession magnetic resonance imaging comprising

• a) means for establishing a magnetic field through an object to be imaged,
• b) means for applying magnetic gradients along three axes through the object,
• c) means for applying a plurality of RF excitation pulses to the object at a sequence repetition rate, the repetition rate being selected to suppress nuclei spin within a spectral range,
• d) means for obtaining multiple datasets after applying multiple RF excitation pulses, and
• e) means for computing discrete Fourier transformed data sets for each pixel in the multiple data sets,
• f) applying complex weighting to the Fourier transformed data sets, and
• g) means for combining weighted Fourier transformed data sets to produce a data set with selective spectral suppression.