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US 8,148,981 B2Granted
MRI apparatus and MRI method for SSFP with center frequency and 1st order gradient moments zeroed
AssigneesKabushiki Kaisha Toshiba, Toshiba Medical Systems Corporation
InventorMasao Yui
Life of this patent
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Abstract
A magnetic resonance imaging apparatus includes an input unit, a data acquisition unit and an image generating unit. The input unit inputs information indicating a matter of which resonance frequency is a center frequency of an excitation pulse. The data acquisition unit acquires magnetic resonance data with obtaining a steady state free precession. Each of the plural excitation pulses has a transmission phase varying by a variation amount determined based on a difference between a resonance frequency and the center frequency. The image generating unit generates an image of the desired matter based on the magnetic resonance data.
Claims16
A magnetic resonance imaging apparatus comprising:
- an input unit configured to input information indicating an object undergoing magnetic resonance imaging of which the resonance frequency of the object undergoing magnetic resonance imaging is a center frequency of an excitation pulse;
- a data acquisition unit configured to acquire magnetic resonance data by obtaining a steady state free precession of a magnetization in a desired object undergoing magnetic resonance imaging by applying plural excitation pulses having a same flip angle with a constant repetition time and gradient magnetic fields to an object, the plural excitation pulses each having a transmission phase varying by a variation amount determined based on a difference between a resonance frequency of a desired object undergoing magnetic resonance imaging and the center frequency defined depending on the object undergoing magnetic resonance imaging;
- and
- an image generating unit configured to generate an image of the desired object undergoing magnetic resonance imaging based on the magnetic resonance data,
- wherein a zero order moment of gradient magnetic field from each application time of the plural excitation pulses till a center time of a corresponding echo is zero, and wherein a zero order moment of gradient magnetic field from each center time of echoes till an application time of a following excitation pulse included in the gradient magnetic fields is zero.
2 more elements
A magnetic resonance imaging apparatus comprising:
- a data acquisition unit configured to acquire magnetic resonance data by obtaining a steady state free precession of a magnetization in a desired object undergoing magnetic resonance imaging by applying plural excitation pulses having a same flip angle with a constant repetition time and gradient magnetic fields to an object, the plural excitation pulses each having a transmission phase varying by a variation amount determined based on a phase shift amount due to a fluctuation of a B0 magnetic filed;
- and
- an image generating unit configured to generate an image of the desired object undergoing magnetic resonance imaging based on the magnetic resonance data,
- wherein a zero order moment of gradient magnetic field from each application time of the plural excitation pulses till a center time of a corresponding echo is zero, and wherein a zero order moment of gradient magnetic field from each center time of echoes till an application time of a following excitation pulse included in the gradient magnetic fields is zero.
1 more element
A magnetic resonance imaging method comprising:
- inputting information indicating a object undergoing magnetic resonance imaging of which resonance frequency is a center frequency of an excitation pulse;
- acquiring magnetic resonance data by obtaining a steady state free precession of a magnetization in a desired object undergoing magnetic resonance imaging by applying plural excitation pulses having a same flip angle with a constant repetition time and gradient magnetic fields to an object, the plural excitation pulses each having a transmission phase varying by a variation amount determined based on a difference between a resonance frequency of a desired object undergoing magnetic resonance imaging and the center frequency defined depending on the object undergoing magnetic resonance imaging;
- and
- generating an image of the desired object undergoing magnetic resonance imaging based on the magnetic resonance data,
- wherein a zero order moment of gradient magnetic field from each application time of the plural excitation pulses till a center time of a corresponding echo is zero, and wherein a zero order moment of gradient magnetic field from each center time of echoes till an application time of a following excitation pulse included in the gradient magnetic fields is zero.
2 more elements
A magnetic resonance imaging method comprising:
- acquiring magnetic resonance data by obtaining a steady state free precession of a magnetization in a desired object undergoing magnetic resonance imaging by applying plural excitation pulses having a same flip angle with a constant repetition time and gradient magnetic fields to an object, the plural excitation pulses each having a transmission phase varying by a variation amount determined based on a phase shift amount due to a fluctuation of a B0 magnetic filed;
- and
- generating an image of the desired object undergoing magnetic resonance imaging based on the magnetic resonance data,
- wherein a zero order moment of gradient magnetic field from each application time of the plural excitation pulses till a center time of a corresponding echo is zero, and wherein a zero order moment of gradient magnetic field from each center time of echoes till an application time of a following excitation pulse included in the gradient magnetic fields is zero.
1 more element
Dependencies are inferred from the claim text.