Scanning method and radio-frequency power calibration method and device of magnetic resonance imaging system

Abstract

The embodiment of the invention discloses a radio-frequency power calibration method of a magnetic resonance imaging system. In the method, radio-frequency pulse amplitudes progressively increasing in a larger step length mode are first selected to undergo traversal scanning during traversal, FID signal values corresponding to the different radio-frequency pulse amplitudes are obtained, the step length is constantly decreased during traversal scanning of the next time, a traversal scanning range is constantly narrowed by determining an initial value and an end point value for traversal again, accordingly the radio-frequency pulse amplitudes corresponding to 90-degree turning angles are quickly and accurately determined, and further a linear relation curve about the turning angles and the radio-frequency pulse amplitudes is obtained according to the 90-degree turning angles and the radio-frequency pulse amplitudes. The radio-frequency power calibration method can quickly and effectively calibrate the radio-frequency power, conveniently provides more accurate calibration structures for different subjects and further obtains 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 ampli

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