2011 Summer Project Week Quantitative Magnetic Susceptibility Mapping

Susceptibility Map 1

Susceptibility Map 2

Full Title of Project

Quantitative Magnetic Susceptibility Mapping

Key Investigators

• MIT: Clare Poynton
• BWH: Sandy Wells

Objective

Quantifying magnetic susceptibility in the brain from the phase of the MR signal provides a non-invasive means for measuring the accumulation of iron believed to occur with aging and neurodegenerative disease.

We describe a variational approach to susceptibility estimation that incorporates a tissue-air atlas to resolve ambiguity in the susceptibility estimates, while eliminating additional biasfields through application of the Laplacian.

Results show improved correlation with postmortem iron concentrations relative to competing methods.

The goal for this week is to apply this method to evaluate magnetic susceptibility of lesions associated with TBI.

Approach, Plan

Our plan for the project week:

• Discuss applications with collaborators and try to refine the algorithm

Progress

• Algorithm: Improved background field correction

  resulting in improved mean susceptibility values: 
  Thalamus ( -0.06 ppm )
  Caudate (0.02 ppm)
  Putamen (0.05 ppm)
  Globus Pallidus (0.11 ppm)

• Applications: Obtained 3 TBI cases from DBP 3, which we are currently analyzing

References