An MRI Inhomogeneous Field Estimation Method Based on Image Gradient Fitting

Abstract

The invention provides an MRI (Magnetic Resonance Imaging) non-uniform field estimation method based on image gradient fitting. The method comprises the following steps: processing an image in a log-domain and decoupling a real image signal and a non-uniform field signal; obtaining the estimation of a non-uniform field through fitting a gradient in an organization region with more uniform grayscale in the image. As gradient processing is performed in the log-domain, a gradient value obtained by a certain pixel is not related to a pixel organization type but is related to the non-uniform field; a special objective function is designed during fitting, so that the estimation of the non-uniform field can be directly obtained through first-order derivatives of the image in an x direction and a y direction without integrating or calculating a second order gradient again.

Description

technical field

[0001] Quickly estimate and correct for inhomogeneous fields in MRI images due to magnetic inhomogeneity or coil sensitivity. Background technique

[0002] Magnetic resonance imaging is widely used in medical diagnosis and scientific research because of its high resolution, no ionizing radiation damage, and imaging at any angle. However, due to the interference of magnetic field inhomogeneity and coil sensitivity, etc., the reconstructed image of the MRI system shows certain inhomogeneity, which will produce certain images for doctor diagnosis and computer-aided analysis such as registration and classification. With the demand for higher-resolution scanning images, the magnetic field strength of the scanner is getting higher and higher, and the magnetic field gradient is getting finer. It's getting serious. The inhomogeneous field is the deviation field caused by the inhomogeneity of the transmitted spatial magnetic field or the inhomogeneity of the receivi...

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