Magnetic resonance imaging system scanning method, radio frequency power calibration method and device

Abstract

The embodiment of the present invention discloses a radio frequency power calibration method for a magnetic resonance imaging system. In this method, when performing traversal, first select the radio frequency pulse amplitude with a larger step size to perform traversal scanning, and obtain different The corresponding FID signal value under the radio frequency pulse amplitude will continuously reduce the step size in the next traversal scan, and by re-determining the start value and end value of the traversal, the range of the traversal scan will be continuously reduced, so as to achieve fast and accurate The radio frequency pulse amplitude corresponding to the 90° flip angle is determined, and then the linear relationship curve between the flip angle and the radio frequency pulse amplitude is obtained from the 90° flip angle and the corresponding radio frequency pulse amplitude. The method can quickly and effectively calibrate the radio frequency power, and is convenient for providing a more accurate calibration structure for different subjects, and further obtaining better imaging quality.

Description

technical field [0001] The invention relates to the field of magnetic resonance imaging systems, in particular to a scanning method for a magnetic resonance imaging system, a radio frequency power calibration method and a device. Background technique [0002] The magnetic resonance imaging system (MRI) uses the combination of pulsed gradient magnetic field and pulsed radio frequency (RF) magnetic field to obtain the magnetic resonance imaging information of the spin protons of the imaging sample placed in the static magnetic field in the designated imaging area. A polarized spin proton placed in a static magnetic field has a net magnetic moment, and the direction of the magnetic moment is the direction of the spin axis of the proton. The direction of the proton spin axis always tends to be along the external static magnetic field , the individual spin protons always precess around the static magnetic field axis at the Larmor frequency of the magnetic spin ratio multiplied ...

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Problems solved by technology

[0006] This calibration method needs to traverse a range of pulse amplitudes during the process, and the scan time is relatively long, usually 30s or more. Usually, it can only be calibrated during the calibration of the entire system. After calibration, the flip angle and radio frequency can be obtained during calibration. The corresponding relationship of pulse amplitude is to determine the radio frequency pulse amplitude for different scanning subjects. However, there are individual differences in different subjects, and the radio frequency pulse amplitude determined for all subjects by only one calibration is not accurate enough, and then It will reduce the signal-to-noise ratio of the image and cannot obtain better image quality

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