Ticept: Wideband Electrical Properties Tomography by Tissue Composition Assessment With Quantitative   1 $$ {}^1 $$ H...

Area of Science:

• Biophysics
• Medical Imaging
• Electromagnetism

Background:

• Accurate dielectric properties are essential for computational modeling in medical device design and safety evaluations.
• Existing methods for dielectric property estimation are often limited in accuracy and provide single-frequency results.
• Noninvasive, wide-frequency range estimation is needed for advanced biomedical applications.

Purpose of the Study:

• To develop a noninvasive method for estimating dielectric properties over a wide frequency range (50-600 MHz).
• To address limitations of existing methods in accuracy and frequency range.
• To support computational modeling in medical device design and safety evaluations.

Main Methods:

• Tissue composition (sodium, potassium, water) was assessed using quantitative MRI techniques ( H, Na, K).
• Measurements were performed in muscle-representative phantoms and six healthy volunteers.
• Mixture models, including Maxwell-Garnett, were employed to correlate dielectric properties with tissue constituents.

Main Results:

• The Maxwell-Garnett model yielded a 7.9% error for real relative permittivity and a 4.0% error for effective conductivity in phantoms.
• In vivo measurements showed values comparable to existing literature.
• Substantial intersubject variability (29%) in effective conductivity was observed.

Conclusions:

• A novel method, H Na K-TiCEPT, was developed for wide-frequency band dielectric property estimation using quantitative MRI.
• The method demonstrates feasibility, with data aligning with literature from 200-600 MHz.
• The findings underscore the need for accurate in vivo dielectric property measurements due to intersubject variability.