Voltage calibration method, magnetic resonance imaging method and magnetic resonance imaging system

A technology of magnetic resonance imaging and voltage calibration, which is applied in the direction of using the nuclear magnetic resonance imaging system for measurement, magnetic resonance measurement, and measurement of magnetic variables. and other problems, to reduce the effect of uniformity and contrast, improve voltage calibration accuracy, and improve image quality.

Active Publication Date: 2017-04-26
SHANGHAI UNITED IMAGING HEALTHCARE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0014] In view of this, the embodiment of this solution provides a voltage calibration method, magnetic resonance imaging method and system to solve the problem of calibrating radio frequency emission voltage in high-field MRI by using the calibration scheme for radio frequency emission voltage in the prior art. , the calibration accuracy is low, and it has a great influence on the uniformity and contrast of the MRI image, resulting in poor quality of the MRI image.

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  • Voltage calibration method, magnetic resonance imaging method and magnetic resonance imaging system
  • Voltage calibration method, magnetic resonance imaging method and magnetic resonance imaging system
  • Voltage calibration method, magnetic resonance imaging method and magnetic resonance imaging system

Examples

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Embodiment 1

[0071] An embodiment of the present invention provides a voltage calibration method, and the flow of the voltage calibration method can be applied to the calibration of radio frequency transmission voltage of a radio frequency system in a magnetic resonance imaging system.

[0072] figure 1 An example flow chart of the voltage calibration method provided by the embodiment of the present invention. Such as figure 1 As shown, in this embodiment, the voltage calibration method may include the following steps:

[0073] S101, according to the scanning sequence, select a scanning layer in the field of view of the region of interest;

[0074] S102, on the selected scanning level, excite the radio frequency pulse at least twice with different initial voltage values ​​as the radio frequency transmission voltage value, and collect the free induction attenuation FID signal and the stimulated echo STE signal obtained each time in the scanning sequence;

[0075] S103, based on the colle...

example 1

[0093] In this example, two-point fitting is used for voltage calibration, and the voltage calibration process is as follows:

[0094] a1, according to the scanning sequence, obtain the FOV (Field of View, field of view) size, position information and slice group information of the pancreatic region, and set the position information and slice group information into the calibration sequence;

[0095] figure 2 An example diagram of the scanning sequence. figure 2 Among them, the scan sequence includes a pre-scan sequence and an imaging sequence, and the pre-scan sequence may also be called a calibration sequence, and the calibration sequence is a layer-selected DREAM (Dual Refocusing Echo Acquisition Mode, dual focusing echo acquisition mode) sequence. Among them, RF (radio Frequency) is the radio frequency transmission pulse; Gss (sliceselect gradient) is the layer selection gradient; Gpe (phase encoding gradient) phase encoding gradient; Gro (readout gradient) is the readou...

example 2

[0118] In this example, three-point fitting is used for voltage calibration, and the voltage calibration process is as follows:

[0119] b1, according to the scanning sequence, obtain the FOV size, position information and slice group information of the pancreas area, and set the position information and slice group information into the calibration sequence;

[0120] figure 2 An example diagram of the scanning sequence. figure 2 Among them, the scan sequence includes a pre-scan sequence and an imaging sequence, and the pre-scan sequence may also be called a calibration sequence, and the calibration sequence is a layer-selected DREAM (Dual Refocusing Echo Acquisition Mode, dual focusing echo acquisition mode) sequence.

[0121] b2, on the selected abdominal level, the initial voltage values ​​V1, V2 and V3 were respectively used as the RF emission voltage values ​​to excite the RF pulse three times, and the FID signals and STE signal;

[0122] Among them, V1=factor1*V ini...

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Abstract

An embodiment of the invention provides a voltage calibration method, a magnetic resonance imaging method and a magnetic resonance imaging system. On one hand, a scanning scope is selected in an interested area according to a scanning sequence. In the selected scanning scope, RF pulse excitation is performed by at least two times through different initial voltages, and an FID signal and an STE signal which are acquired in each time by the scanning sequence are acquired. Based on the acquired signals, an overturning angle mean value in an interested area which corresponds with each initial voltage is determined. By means of each initial voltage and a corresponding overturning angle mean value, reference voltage which corresponds an objective overturning angle is acquired through linear fitting. The voltage calibration method, the magnetic resonance imaging method and the magnetic resonance imaging system have advantages of reducing effects of RF field distribution non-uniformity and partial difference of an integral scanning image overturning angle to voltage calibration of an interested area, improving voltage calibration precision of an interested area, reducing an effect to uniformity and contrast of the interested area in the MRI image, and improving image quality of the interested area in the MRI image.

Description

[0001] 【Technical field】 [0002] The solution relates to the technical field of magnetic resonance imaging, in particular to a voltage calibration method, a magnetic resonance imaging method and a system. [0003] 【Background technique】 [0004] Currently, MRI (Magnetic Resonance Imaging, Magnetic Resonance Imaging) systems are widely used in the medical field. The image information of human tissue obtained by the MRI system can assist doctors in diagnosis of diseases and can also be used for medical research. [0005] The radio frequency system in the MRI system will emit radio frequency pulses under the excitation of radio frequency emission voltage. Under the action of radio frequency pulses, the macroscopic magnetization vector of human tissue will deviate from the equilibrium state, and the angle of deviation is the flip angle. In order to make the RF pulse emitted by the RF system reach the required flip angle, it is necessary to calibrate the amplitude of the RF emissi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R33/48G01R33/58
CPCG01R33/48G01R33/586
Inventor 蒋瑞瑞
Owner SHANGHAI UNITED IMAGING HEALTHCARE
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