High resolution/reduced slice width magnetic resonance imaging and spectroscopy by signal combination and use of minimum phase excitation pulses

Claim 3

The method as defined by claim 1 wherein steps (e), (f), and (g) are repeated.

Claim 4

The method as defined by claim 1 wherein said first trajectory covers positive k z and said second trajectory covers negative k z .

Claim 5

The method as defined by claim 3 wherein step (h) emphasizes the y component of the slice profile and cancels the x component of the slice profile.

Claim 6

The method as defined by claim 4 wherein said magnetic gradient (G z ) is a triangular wave.

Claim 7

The method as defined by claim 5 wherein said RF pulses have sharp nulls where said gradient is zero.

Claim 8

The method as defined by claim 5 wherein said RF excitation pulses have a minimum-phase spectral weighting to limit spectral dephasing.

Claim 9

The method as defined by claim 1 wherein said RF excitation pulses have a minimum-phase spectral weighting to limit spectral dephasing.

Claim 10

The method as defined by claim 1 wherein said first trajectory and said second trajectory criss-cross in k-space.

Claim 11

The method as defined by claim 9 wherein said magnetic gradient (G z ) is a triangular wave, and said RF pulses have sharp nulls where said gradient is zero.

Claim 12

The method as defined by claim 10 wherein said RF excitation pulses have a minimum-phase spectral weighting to limit spectral dephasing.

Claim 13

The method as defined by claim 1 wherein said magnetic gradient (G z ) has a shape selected from a group consisting of triangular, trapezoidal, and sinusoidal.

Claim 14

Apparatus for obtaining a magnetic resonance from a slice through a body which is spatially and spectrally selective comprising a) a means for applying a static magnetic field (B o ) to said boy thereby aligning nuclear spins, b) means for applying a first RF excitation pulse (RF) to said body to tip said nuclear spins, c) means for applying a modulated magnetic gradient (G z ) simultaneously with step (b), the waveform of said gradient and the waveform of said first pulse profile being related whereby k-space has a first trajectory, d) means for detecting a first magnetic resonance signal, e) means for applying a second RF excitation pulse (RF) to said body to tip said nuclear spins, f) means for modifying the waveform of said modulated magnetic gradient (G z ) and applying the modified modulated magnetic gradient (G z ) simultaneously with step (e) whereby k-space has a second trajectory, g) means for detecting a second magnetic resonance signal, and h) means for combining said first magnetic resonance signal and said second magnetic resonance signal to produce an enhanced magnetic resonance signal.

Claim 15

Apparatus for obtaining a magnetic resonance from a slice through a body which is spatially and spectrally selective comprising a) a means for applying a static magnetic field (B o ) to said boy thereby aligning nuclear spins, b) means for applying a first RF excitation pulse (RF) to said body to tip said nuclear spins, c) means for applying a modulated magnetic gradient (G z ) simultaneously with step (b), the waveform of said gradient and the waveform of said first pulse profile being related whereby k-space has a first trajectory, d) means for detecting a first magnetic resonance signal, e) means for applying a second RF excitation pulse (RF) to said body to tip said nuclear spins, f) means for modifying the waveform of said modulated magnetic gradient (G z ) and applying the modified modulated magnetic gradient (G z ) simultaneously with step (e) whereby k-space has a second trajectory, g) means for detecting a second magnetic resonance signal, and h) means for combining said first magnetic resonance signal and said second magnetic resonance signal to produce an enhanced magnetic resonance signal.

Claim 16

Apparatus as defined by claim 13 wherein said magnetic gradient (G z ) is a triangular wave, and said RF pulses have sharp nulls where said gradient is zero.

Claim 17

Apparatus as defined by claim 13 wherein said RF excitation pulses have a minimum-phase spectral weighting to limit spectral dephasing.

Claim 18

Apparatus as defined by claim 13 wherein said magnetic gradient (G z ) has a shape selected from a group consisting of triangular, trapezoidal, and sinusoidal.