Visualization of Tendon Organization and Fascicle Crossover in 3D Using Micro-CT
Abstract
Micro-computed tomography (CT) is an x-ray-based imaging modality that produces three-dimensional (3D), high-resolution images of whole-mount tissues, but is limited to dense tissues, such as bone. The x-rays readily pass through tendons, rendering them transparent. Contrast-enhancing chemical stains have been explored, but their use to improve contrast in tendon for micro-CT imaging had not been systematically evaluated. To address this, our previous investigation showed that phosphotungstic acid (PTA) staining increased x-ray absorption of tendon to enhance tissue contrast and obtain 3D micro-CT images of rat tendons within the tail and hindlimb. Further, we demonstrated that tissue hydration state significantly impacts soft tissue contrast. Utilizing this new contrast enhancing method, 3D images from tissues were analyzed and processed to identify and trace tendon fascicles and analyze the anatomical organization of the tail and hind limb. From this analysis, we found that tail tendon fascicles appeared to cross between fascicle bundles, whereas it was assumed that the fascicle bundles maintain specific tracks within the tendon. Based on these initial findings, we extended our study and investigated the tails and hind limbs of younger and older, sexually mature rats to evaluate tendon fascicle crossover as a function of age. Ultimately, contrast-enhanced 3D micro-CT imaging will lead to better understanding of tendon structure, and relationships between the bone and soft tissues.
Visualization of Tendon Organization and Fascicle Crossover in 3D Using Micro-CT
Micro-computed tomography (CT) is an x-ray-based imaging modality that produces three-dimensional (3D), high-resolution images of whole-mount tissues, but is limited to dense tissues, such as bone. The x-rays readily pass through tendons, rendering them transparent. Contrast-enhancing chemical stains have been explored, but their use to improve contrast in tendon for micro-CT imaging had not been systematically evaluated. To address this, our previous investigation showed that phosphotungstic acid (PTA) staining increased x-ray absorption of tendon to enhance tissue contrast and obtain 3D micro-CT images of rat tendons within the tail and hindlimb. Further, we demonstrated that tissue hydration state significantly impacts soft tissue contrast. Utilizing this new contrast enhancing method, 3D images from tissues were analyzed and processed to identify and trace tendon fascicles and analyze the anatomical organization of the tail and hind limb. From this analysis, we found that tail tendon fascicles appeared to cross between fascicle bundles, whereas it was assumed that the fascicle bundles maintain specific tracks within the tendon. Based on these initial findings, we extended our study and investigated the tails and hind limbs of younger and older, sexually mature rats to evaluate tendon fascicle crossover as a function of age. Ultimately, contrast-enhanced 3D micro-CT imaging will lead to better understanding of tendon structure, and relationships between the bone and soft tissues.