In vivo lipid diffusion coefficient measurements in rat bone marrow

Area of Science:

• Biophysics
• Medical Imaging
• Biochemistry

Background:

• Lipid diffusion coefficients (D(l)) are influenced by composition and temperature.
• Altered D(l) may indicate diseases like cystic fibrosis, diabetes, and coronary heart disease.
• D(l) temperature dependence is relevant for MR-guided thermal therapies in fatty tissues.

Purpose of the Study:

• To develop and test advanced imaging methods for measuring in vivo lipid diffusion coefficients.
• To assess the feasibility of using D(l) for disease diagnosis and thermal therapy guidance.

Main Methods:

• Designed and implemented high b-factor line scan diffusion imaging sequences.
• Utilized a 4.7-T animal scanner with high gradient performance (b-factors up to 30,000 s/mm²).
• Conducted in vivo measurements in rat bone marrow and phantom experiments.

Main Results:

• Successfully measured lipid diffusion coefficients in rat paw marrow in vivo.
• Obtained D(l) values approximately two orders of magnitude lower than water diffusion coefficients.
• Phantom studies confirmed sensitivity of D(l) to lipid chain length and temperature.

Conclusions:

• High b-factor diffusion imaging is a viable method for measuring in vivo lipid diffusion.
• Measured D(l) values provide a baseline for understanding lipid dynamics in health and disease.
• This technique holds potential for clinical applications in diagnostics and thermal therapy.