Detection of susceptibility effects using simultaneous T(2)* and magnetic field mapping

Area of Science:

• Biomedical Imaging
• Magnetic Resonance Imaging (MRI)
• Tissue Characterization

Background:

• Susceptibility effects in MRI are useful for detecting small inclusions within bulk tissues.
• Quantitative assessment of these effects can improve diagnostic accuracy.
• Existing methods may lack sensitivity for mesoscopic variations.

Purpose of the Study:

• To propose and validate a quantitative method for assessing magnetic susceptibility effects in tissues using MRI.
• To simultaneously map T(2)* and magnetic fields to characterize susceptibility variations.
• To investigate the susceptibility effects generated by connective tissue in muscle.

Main Methods:

• Utilized a multiple Gradient Echo (GE) sequence at 4.7 Tesla.
• Simultaneously mapped T(2)* and magnetic fields from the time course of magnitude and phase data.
• Introduced a high-pass filtering scheme to enhance mesoscopic magnetic field variations.

Main Results:

• Successfully demonstrated simultaneous mapping of T(2)* and magnetic fields.
• The high-pass scheme effectively highlighted local magnetic field variations due to susceptibility differences.
• Applied to muscle tissue, the method detected significant susceptibility effects from connective tissue.

Conclusions:

• The proposed quantitative MRI method enables sensitive detection of susceptibility effects.
• Connective tissue in muscle exhibits detectable magnetic susceptibility effects.
• These effects manifest as local magnetic field variations and T(2)* shortening.