Alternating gradients for metal-induced artifacts correction in magnetic resonance imaging

Patent metadata

Field	Value
Publication number	US-10768261-B2
Application number	US-201815921495-A
Country	US
Kind code	B2
Filing date	Mar 14, 2018
Priority date	Mar 15, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A method for magnetic resonance imaging suppresses off-resonance gradient-induced image artifacts due to metal. The method includes performing by a magnetic resonance imaging (MRI) apparatus two multi-spectral imaging (MSI) acquisitions within a field of view of the MRI apparatus, where the two MSI acquisitions have alternating-sign readout gradients. The two MSI acquisitions are then processed and combined by the MRI apparatus using a weighted image combination to produce a final image.

First claim

The invention claimed is:

1. A method for magnetic resonance imaging that suppresses off-resonance gradient-induced image artifacts due to metal, the method comprising:
performing by a magnetic resonance imaging (MRI) apparatus two multi-spectral imaging (MSI) acquisitions within a field of view of the MRI apparatus, where the two MSI acquisitions have alternating-sign readout gradients during signal readout; and
processing and combining by the MRI apparatus the two MSI acquisitions using a weighted image combination to produce a final image;
wherein combining the two MSI acquisitions using the weighted image combination comprises weighting a MSI acquisition m + with weight w + , weighting a MSI acquisition m − with weight w − , where the weights w + and w − include effects of both an RF excitation weight w RF and local gradient weight w G , and where MSI acquisition m + and MSI acquisition m − have opposite directions of readout gradients.

2. The method of claim 1 wherein the two MSI acquisitions have alternating-sign slice-select gradients and view-angle tilting gradients.

3. The method of claim 1 wherein the RF excitation weight w RF and the local gradient weight w G are determined from a composite field map f.

4. The method of claim 3 wherein the composite field map f is determined from MSI acquisition m + , MSI acquisition m − , and corresponding field maps f + and f − .

Assignees

• Univ Leland Stanford Junior

Inventors

• Shi Xinwei
• Hargreaves Brian A

Classifications

• G01R33/4835

  of multiple slices · CPC title

• G06T2207/10088

  Magnetic resonance imaging [MRI] · CPC title

• G01R33/5608

  Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels (image data processing or generation, in general G06T) · CPC title

• G01R33/56536 Primary

  due to magnetic susceptibility variations · CPC title

• G06T2207/20221

  Image fusion; Image merging · CPC title