title: The functional microstructure of tendon collagen revealed by high-field MRI.
abstract: T2 was used in this study to assess tendon microstructure. Two unloaded digital extensor tendons were bent such that their long axes were imaged throughout 180° with respect to B0. T2-weighted images reveal periodic banding (∼200 μm) when tendons were oriented at ±55° with respect to B0. Five pairs of tendons were used to study the influence of load on T2W MRI: one tendon of each pair was loaded with a 7.8-N mass, and both tendons were fixed in formalin then imaged at 55° to B0. MRI banding was present in the unloaded, but not loaded, tendons. In unloaded tendons, polarized-light microscopy revealed collagen crimp with a periodicity similar to MRI. In loaded tendons, there was a strain-induced extinction of periodicity on both MRI and polarized-light microscopy. These studies confirm that crimp is detectable by high-field MRI and could serve as an in vivo index of physiological strains in collagenous tissues.
authors.affiliation: Department of Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Kelsey M
authors.initials: KM
authors.lastname: Mountain
authors.forename: Thorarin A
authors.initials: TA
authors.lastname: Bjarnason
authors.forename: Jeff F
authors.initials: JF
authors.lastname: Dunn
authors.forename: John R
authors.initials: JR
authors.lastname: Matyas
mesh_terms: D000465:Algorithms; D000818:Animals; D003094:Collagen / Q000648:ultrastructure*; D004285:Dogs; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013710:Tendons / Q000648:ultrastructure*
chemical_list: D003094:Collagen