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Related Experiment Video

Updated: Mar 19, 2026

Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla

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Published on: February 19, 2021

Single-step quantitative susceptibility mapping with variational penalties.

Itthi Chatnuntawech¹, Patrick McDaniel¹, Stephen F Cauley^2,3

¹Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA.

NMR in Biomedicine

|June 23, 2016

Summary

This summary is machine-generated.

New single-step quantitative susceptibility mapping (QSM) methods improve accuracy and reduce artifacts by combining background removal and dipole inversion. These advanced algorithms offer better magnetic susceptibility estimation for medical imaging.

Keywords:

Wave-CAIPI alternating direction method of multipliers (ADMM)quantitative susceptibility mapping (QSM)total generalized variation (TGV)total variation (TV)

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Area of Science:

Medical Imaging
Biophysics
Computational Neuroscience

Background:

Quantitative susceptibility mapping (QSM) traditionally involves multi-step processes for magnetic susceptibility estimation.
These steps, background phase removal and dipole inversion, are ill-posed inverse problems requiring regularization.
Existing methods can be complex and prone to artifacts, necessitating improved algorithms.

Purpose of the Study:

To develop and validate efficient single-step QSM algorithms.
To mitigate artifacts and improve the accuracy of magnetic susceptibility mapping.
To integrate background removal and dipole inversion into a unified framework.

Main Methods:

Employed total variation (TV) and total generalized variation (TGV) for joint background removal and dipole inversion.
Utilized multiple spherical mean value (SMV) kernels for high-fidelity background removal while preserving cortical phase information.
Developed algorithms with simple analytical solutions for optimization steps.

Main Results:

Numerical simulations showed up to a 66% reduction in reconstruction error compared to multi-step methods.
In vivo experiments demonstrated significant reduction in dipole streaking artifacts.
Achieved improved homogeneity of image contrast using rapid 3D EPI and Wave-CAIPI trajectories.

Conclusions:

Single-step QSM offers a more efficient and accurate approach to magnetic susceptibility mapping.
The proposed methods effectively reduce artifacts and enhance image quality.
Demonstrated the potential of Wave-CAIPI for efficient whole-brain imaging and introduced automated coil sensitivity estimation.