CSI-EPT: A Contrast Source Inversion Approach for Improved MRI-Based Electric Properties Tomography

Area of Science:

• Biomedical Imaging
• Electromagnetism
• Medical Physics

Background:

• Electric Properties Tomography (EPT) reconstructs electric conductivity and permittivity using MRI-derived B1(+) maps.
• Current EPT methods, based on local Maxwell equations, struggle with noise and boundary accuracy due to piecewise constant media assumptions.

Purpose of the Study:

• To introduce a novel multiplicative regularized contrast source inversion-EPT (CSI-EPT) method.
• To improve the accuracy of electric property reconstruction, particularly near tissue boundaries and for small structures.

Main Methods:

• Developed an iterative CSI-EPT approach using integral electromagnetic field representations.
• Incorporated a multiplicative Total Variation factor for noise suppression.
• Enabled simultaneous use of multiple B1(+) datasets from complementary RF excitation settings.

Main Results:

• Demonstrated improved reconstruction accuracy near tissue boundaries in in vivo pelvic model simulations.
• Showcased the capability of CSI-EPT to reconstruct small tissue structures.
• Validated the effectiveness of using complementary B1(+) fields for enhanced reconstruction.

Conclusions:

• The proposed multiplicative regularized CSI-EPT method offers superior accuracy and noise suppression compared to conventional EPT.
• This technique holds promise for more detailed and reliable imaging of electric properties within the human body.