Ultrashort Echo Time Double Echo Steady-State MRI for Quantitative Conductivity Mapping in the Knee: A Feasibility...

Area of Science:

• Medical Imaging
• Biophysics
• Biomaterials

Background:

• Tissue conductivity, reflecting ionic composition like sodium, is vital for understanding disease.
• Ultrashort echo time quantitative conductivity mapping (UTE-QCM) is effective for musculoskeletal (MSK) tissues with short T2 relaxation times.

Purpose of the Study:

• Develop and validate a UTE-QCM framework using ultrashort echo time double echo steady-state (UTE-DESS) sequences.
• Assess the feasibility of UTE-QCM for knee imaging.

Main Methods:

• Acquired S+ and S- images using a UTE-DESS sequence at 3T to estimate B1+ phase.
• Processed phase data using parabolic fitting and integral-based quantitative conductivity mapping (QCM) methods.
• Validated the UTE-QCM framework in sodium chloride phantoms and in vivo knee imaging of healthy volunteers.

Main Results:

• The integral-based QCM method showed superior noise robustness over parabolic fitting in phantom and in vivo experiments.
• Estimated conductivity in the sodium phantom exhibited high linearity with varying sodium concentrations.
• Generated conductivity maps effectively visualized both long and short T2 tissues in the knee.

Conclusions:

• Demonstrated the feasibility of UTE-QCM as a novel quantitative imaging tool for short T2 tissues in the MSK system.
• This technique holds potential for improving the diagnosis and prognosis of joint disorders.