Relationship between Relaxation Component T2 Values & Weight Fractions & Mechanical Moduli in Native Cartilage

Onyi Irrechukwu¹, Sarah von-Thaer¹, Eliot Frank², David Reiter¹, Alan Grodzinsky², Richard Spencer¹

The objective of this study was to correlate the components and fractions determined from multiexponential analysis of cartilage transverse relaxation with tissue mechanical properties. Analysis was performed on bulk T2 relaxation data obtained from bovine nasal cartilage explants. Identical explants were mechanically tested in unconfined compression to determine matrix dynamic and equilibrium moduli. Four relaxation components, interpreted in terms of tissue water compartments, were detected in all explants. Compressive moduli were positively correlated with fractions representing macromolecules and negatively correlated with macromolecular component T2 values. This is consistent with increased stiffness resulting from increasing macromolecular concentration and decreasing water mobility.