To mask or not to mask? Investigating the impact of accounting for spatial frequency distributions and susceptibility sources on QSM quality

TL;DR

This paper examines how considering spatial frequency distributions and susceptibility sources affects the accuracy of magnetic susceptibility estimation in MRI, emphasizing the importance of proper modeling for reliable results.

Contribution

It introduces the significance of accounting for spatial frequency and susceptibility source effects in susceptibility fitting, which has been overlooked in prior methods.

Findings

Ignoring these effects can lead to inaccurate susceptibility estimates.

Proper modeling improves the reliability of QSM results.

The study highlights the necessity of considering measurement constraints in susceptibility estimation.

Abstract

Estimating magnetic susceptibility using MRI depends on inverting a forward relationship between the susceptibility and measured Larmor frequency. However, an often-overlooked constraint in susceptibility fitting is that the Larmor frequency is only measured inside the sample, and after background field removal, susceptibility sources should only reside inside the same sample. Here we test the impact of accounting for such effects in susceptibility fitting and demonstrate that such effects should not be ignored.