Investigation of Collagen Fiber Crimp Morphology and Microstructural Organization in Annulus Fibrosus by Ultra High-Field Mri

Degenerative disc disease (DDD) is a condition that affects the biochemical and biomechanical integrity and function of intervertebral discs. While the causes of DDD are many, changes to the mechanical behavior and extracellular matrix (ECM) of annulus fibrosus (AF) have been documented. Collagen is a major component of the ECM and has a specialized organization and morphology that is functionally significant. There are limited non-invasive modalities capable of visualizing collagen fiber morphology and AF architecture at the microscopic level. The objective was to investigate the three-dimensional collagen microstructure within healthy bovine AF by ultra high-field (9.4T) magnetic resonance imaging (MRI). Collagen crimp and trans lamellar cross bridges were detected along surface and interior AF. Fiber bundles were also shown to reorient following circumferential tension. Together, an MRI protocol and model has been developed to detect mechanically relevant markers that could be used to better understand structural and biomechanical changes with degeneration.

Keywords: Annulus Fibrosus; Collagen Fiber Crimp; Magnetic Resonance Imaging; Trans Lamellar Cross Bridges; Magic Angle Effect

Year	Entry
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Year

Entry

2000

Kannus P. Structure of the tendon connective tissue. Scand J Med Sci Sports. December 2000;10(6):312-320.

2011

Makris EA, Hadidi P, Athanasiou KA. The knee meniscus: structure–function, pathophysiology, current repair techniques, and prospects for regeneration. Biomaterials. October 2011;32(30):7411-7431.

1987

Stokes IAF. Surface strain on human intervertebral discs. J Orthop Res. 1987;5(3):348-355.

1980

Hickey DS, Hukins DWL. Relation between the structure of the annulus fibrosus and the function and failure of the intervertebral disc. Spine. March–April 1980;5(2):106-116.

2005

Iatridis JC, MacLean JJ, Ryan DA. Mechanical damage to the intervertebral disc annulus fibrosus subjected to tensile loading. J Biomech. March 2005;38(3):557-565.