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US 8,797,032 B2Granted
Magnetic resonance imaging apparatus and magnetic resonance imaging method
AssigneesKabushiki Kaisha Toshiba, Toshiba Medical Systems Corporation
InventorMasashi Ookawa
Life of this patent
Estimating the term…
Abstract
The temperature of an MRI gradient magnetic field coil unit is measured at least two times. Shift data indicating a center magnetic resonance frequency of a hydrogen atom in response to variation of the gradient coil temperature is stored in advance. Estimated shift of the center frequency based on the measurement result is determined and the center frequency of an RF NMR excitation pulse is corrected based on the estimated shift.
Claims21
A magnetic resonance imaging (MRI) apparatus, comprising:
- an MRI gradient magnetic field coil unit configured to generate a gradient magnetic field in an imaging space according to a current supplied thereto;
- at least one temperature sensor configured to measure a temperature of the MRI gradient magnetic field coil unit at least two times at different timings to detect at least one coil unit temperature difference between said different timings;
- a data store in which shift data have been recorded in advance of measurements by the temperature sensor, the shift data indicating a shift of a center frequency of hydrogen atom nuclear magnetic resonance (NMR) in the imaging space as a function of variation of gradient magnetic field coil unit temperature;
- a pulse setting unit configured to acquire a measurement result from the temperature sensor, to determine an estimated shift of the hydrogen atom NMR center frequency using the detected variation of temperature and the stored shift data, and to correct an RF pulse center frequency based on the estimated shift;
- and
- an imaging unit configured to transmit the corrected RF pulse to receive magnetic resonance signals from an object in the imaging space, and to generate image data of the object based on the received magnetic resonance signals.
3 more elements
A magnetic resonance imaging (MRI) method comprising:
- measuring a temperature of an MRI gradient magnetic field coil unit, which generates a gradient magnetic field in an imaging space according to a current supplied thereto, at least two times at different timings to detect at least one coil unit temperature difference between said different timings;
- recalling from memory, previously stored shift data indicating shift of a center frequency of hydrogen atom nuclear magnetic resonance (NMR) in the imaging space as a function of variation of the gradient magnetic field coil unit temperature;
- determining an estimated shift of the hydrogen atom NMR center frequency using the detected variation of temperature and the stored shift data,
- correcting an RF pulse center frequency based on the estimated shift;
- and
- generating image data of an object based on magnetic resonance signals by transmitting the center frequency corrected RF pulse and receiving magnetic resonance signals from the object in the imaging space.
3 more elements
Dependencies are inferred from the claim text.