Quantitative two-dimensional ultrashort echo time magnetization transfer (2D UTE-MT) imaging of cortical bone

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Bone Biology

Background:

• Cortical bone's structural integrity is crucial for skeletal function.
• Quantitative imaging techniques are needed to assess bone properties non-invasively.
• Magnetization transfer (MT) imaging offers potential for probing tissue microstructure.

Purpose of the Study:

• To investigate quantitative 2D ultrashort echo time magnetization transfer (UTE-MT) imaging in ex vivo bovine and in vivo human cortical bone.
• To apply a two-pool quantitative MT model to characterize bone tissue parameters.

Main Methods:

• Acquired 2D UTE-MT data from bovine and human cortical bone samples using a clinical 3T scanner.
• Employed a two-pool quantitative MT model to derive macromolecular fraction (f), T2m, R1w, RM0m, and RM0w.
• Conducted an air-drying study to assess parameter sensitivity to water loss.

Main Results:

• Mean values for f, T2m, R1w, RM0m, and RM0w were determined for both bovine and human cortical bone.
• In vivo human cortical bone exhibited comparable quantitative MT parameters to ex vivo bovine bone.
• The air-drying study indicated that f, RM0m, and R1w are sensitive to changes in water content.

Conclusions:

• Quantitative 2D UTE-MT imaging, analyzed with a two-pool model, provides valuable quantitative information about cortical bone.
• This technique offers a novel approach for assessing bone tissue characteristics.
• The findings suggest UTE-MT imaging's potential for evaluating bone health and disease.