Magnetic resonance diffusion imaging method

Abstract

The invention provides a magnetic resonance diffuse imaging method. At least two reunion phase radio frequency pulses are added at the back of an excitation radio frequency pulse of a magnetic resonance diffuse imaging pulse sequence, and two sides of each reunion phase radio frequency pulse are symmetrically provided with a diffuse sensitive gradient, wherein two sides of each reunion phase radio frequency pulse are symmetrically provided with a destroying gradient which is placed between the reunion phase radio frequency pulse and the diffuse sensitive gradients at two sides of the reunion phase radio frequency pulse and is used for completely dispelling the phase of the transverse magnetized vector to eliminate the artifact. At least one of a lamella selecting gradient, a phase coding gradient and a numerating gradient direction is provided with the destroying gradient to completely dispelling the phase of the transverse magnetized vector to achieve the steady and balanced state and eliminate the artifact of the diffuse imaging, and at the same time the characteristic of high b value is retained.

Description

technical field [0001] The invention relates to a magnetic resonance imaging technology, in particular to a magnetic resonance diffusion imaging method. Background technique [0002] Among the various imaging techniques of magnetic resonance, magnetic resonance diffusion weighted imaging (Diffusion Weighted Imaging, DWI) is a newly developed one, which uses tissue contrast produced by different diffusion coefficients between tissues to perform imaging, which is different from conventional magnetic resonance imaging. Resonance imaging method, which can non-invasively examine the tissue structure and functional state of organisms at the molecular level. [0003] Diffusion is the Brownian motion caused by thermal motion of water molecules inside the tissue, which is arbitrary and irregular. Diffusion is divided into free diffusion and restricted diffusion. The diffusion distance of free diffusion is linearly proportional to the diffusion time; the diffusion distance of restric...

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Problems solved by technology

[0009] However, in practical applications, the above-mentioned rephasing radio frequency pulses are not perfect 180° radio frequency pulses in some cases, such as in the case of magnet eddy current or insufficient radio frequency power caused by the induced alternating current of the gradient pulse , or in some imaging sequences using rephasing RF pulses with flip angles less than 180°, can cause splitting of the magnetization vector components, resulting in transverse magnetization vectors that form multiple additional echoes that overlap each other causing artifacts

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