Ultrashort echo time spectroscopic imaging (UTESI): an efficient method for quantifying bound and free water

Area of Science:

• Biomedical Imaging
• Biophysics
• Musculoskeletal Science

Background:

• Biological tissues possess distinct water compartments influencing their properties.
• Characterizing water in musculoskeletal tissues is crucial for understanding tissue health and disease.
• Previous methods lacked the speed and precision to differentiate water states in vivo.

Purpose of the Study:

• To evaluate the efficacy of ultrashort echo time spectroscopic imaging (UTESI) with bi-component analysis.
• To quantify bound and free water components in musculoskeletal tissues.
• To assess the clinical feasibility of UTESI for musculoskeletal imaging.

Main Methods:

• Two-dimensional, multi-slice, ultrashort echo time spectroscopic imaging (UTESI) was employed.
• Bi-component analysis was used to differentiate water populations based on T(2)* relaxation times.
• Imaging was performed on numerical simulations, bovine cortical bone, human cadaveric menisci, and volunteer Achilles' tendons.

Main Results:

• UTESI reliably quantified short and long T(2)* components and their fractions in simulations.
• In vitro and in vivo studies were completed in under 14 minutes.
• Distinct T(2)* values and fractions for bound and free water were measured across bone, meniscus, and tendon.

Conclusions:

• UTESI combined with bi-component analysis can accurately quantify bound and free water in musculoskeletal tissues.
• The method achieves this quantification within clinically relevant timeframes.
• This technique offers a promising tool for musculoskeletal research and diagnostics.