Spherical k-space acquisition method and device for three-dimensional dynamic magnetic resonance imaging

Abstract

The invention provides a spherical k space acquisition method and device for three-dimensional dynamic magnetic resonance imaging. The method includes the steps: building a spherical k space model and determining acquisition track codes of echo signals in the model; inputting the acquisition track codes to a magnetic resonance imaging system and acquiring k space data for filling the spherical k space model according to the acquisition track codes. The echo signals are radial half echo signals from a sphere center to a spherical surface in a sphere or diameter full echo signals passing the sphere center, and the elevation angle theta and the azimuth angle phi of the echo signals are calculated according to a two-dimensional golden division ratio. According to the method, the three-dimensional k space data can be continuously acquired, the acquired k space data are approximately uniformly distributed in an optional time window, and continuous three-dimensional dynamic image reconstruction and high time resolution three-dimensional dynamic magnetic resonance imaging can be realized.

Description

technical field [0001] The present application relates to the technical field of three-dimensional dynamic magnetic resonance imaging, in particular to a spherical k-space acquisition method and device for three-dimensional dynamic magnetic resonance imaging. Background technique [0002] Magnetic resonance imaging (Magnetic Resonance Imaging, MRI) is to use the nuclear magnetic resonance phenomenon to excite the spin nuclei in the human body, and then receive the electromagnetic signals released by the spin nuclei to reconstruct the image information of the human body tissue. With the advantages of high contrast, it has become an important tool for clinical medical examination. The data collected in the process of magnetic resonance imaging is called k-space data, and all the data constitute k-space as a whole. The acquisition trajectory used is called k-space trajectory, and the magnetic resonance image can be obtained by reconstructing the k-space data. Dynamic magnetic ...

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Problems solved by technology

For these two types of methods, the reconstruction of a set of 3D dynamic images requires repeated collection of all or a large amount of 3D k-space data, so the time resolution is low, and the k-space data within a specific time window needs to be selected for image reconstruction. The acquisition of the next time window is carried out in the next time window to ensure that the magnetic resonance data in the k-space are evenly distributed, so the freedom of image reconstruction is limited

In addition, there is a Cartesian and radial hybrid acquisition method, which uses radial acquisition in the plane and Cartesian acquisition in the gradient direction of layer selection. Although the acquisition time can be reduced to a certain extent by under-sampling acquisition, the k-space data is uniform The performance is still limited by the encoding scheme of a certain dimension, and the time resolution of dynamic imaging is difficult to improve

In addition, most of the existing dynamic magnetic resonance imaging technologies realize dynamic imaging by reconstructing the data after screening and recombination in the later stage, so it is generally difficult to obtain continuous dynamic images

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