X-ray computed tomography of the anterior cruciate ligament and patellar tendon

Abstract

SummaryThe effect of phosphotungstic acid (PTA) and iodine solution (IKI) staining was investigated as a method of enhancing contrast in the X-ray computed tomography of porcine anterior cruciate ligaments (ACL) and patellar tendons (PT). We show that PTA enhanced surface contrast, but was ineffective at penetrating samples, whereas IKI penetrated more effectively and enhanced contrast after 70 hours of staining. Contrast enhancement was compared when using laboratory and synchrotron based X-ray sources. Using the laboratory source, PT fascicles were tracked and their alignment was measured. Individual ACL fascicles could not be identified, but identifiable features were evident that were tracked. Higher resolution scans of fascicle bundles from the PT and ACL were obtained using synchrotron imaging techniques. These scans exhibited greater contrast between the fascicles and matrix in the PT sample, facilitating the identification of the fascicle edges; however, it was still not possible to detect individual fascicles in the ACL.

Three-dimensional visualisation of the internal anatomy of the sparrowhawk (Accipiter nisus) forelimb using contrast-enhanced micro-computed tomography

“…A variety of agents (e.g. phosphotungstic acid (PTA), phosphomolybdenic acid (PMA), osmium tetroxide, and iodine-based solutions) have been tested in both vertebrates and invertebrates and have proved to be a suitable tool for soft tissue visualisation of fishes (Metscher, 2009a; Descamps et al, 2014), amphibians (Metscher, 2009a; Kleinteich & Gorb, 2015), reptiles (Tsai & Holliday, 2011; Gröning et al, 2013), birds (Düring et al, 2013; Lautenschlager, Bright & Rayfield, 2014; Li et al, 2015; Hieronymus, 2016), mammals (Cox & Jeffery, 2011; Jeffery et al, 2011; Stephenson et al, 2012; Aslanidi et al, 2013; Baverstock, Jeffery & Cobb, 2013; Cox & Faulkes, 2014; Shearer et al, 2014), vertebrate embryos (Metscher, 2009b; Degenhardt et al, 2010; Tahara & Larsson, 2013; Descamps et al, 2014; Gignac & Kley, 2014), and invertebrates (Metscher, 2009b; Faulwetter et al, 2013; Boyde et al, 2014). …”

Three-dimensional visualisation of soft biological structures by X-ray computed micro-tomography

“…1. Recently, there have been substantial advances in microCT technology, both in terms of the types of scanner available, which now allow sub-micron resolution, capture of phase-contrast information and faster scan acquisition, and in the development of imaging protocols (Withers, 2007;Stock, 2008;Bravin et al, 2013;Maire and Withers, 2014;Shearer et al, 2014;Balint et al, 2016). Collectively, these advances can be exploited to image soft (non-calcified) tissues.…”

“…To date, certain contrast agents (such as iodine and phosphotungstic acid, for example) have been widely used because they meet several of the criteria above. However, these contrast agents are not perfect; iodine is known to cause substantial sample shrinkage (Vickerton et al, 2013) and phosphotungstic acid perfusion can take a long time, making it unsuitable for larger samples (Shearer et al, 2014).…”

“…One potential cause of these differences in mechanical performance could be the microstructural differences between the ACL and the graft tendons that have been used to replace it during reconstruction. Therefore, to visualise and quantify differences in the 3D internal structure of tendons and ligaments, we used microCT to identify key geometrical differences in the arrangement of fascicles within porcine ACLs and patellar tendons that had been chemically fixed and stained with an iodine-based (I 2 KI) X-ray contrast agent (Shearer et al, 2014). Because this microCT approach allowed us to rapidly visualise (24 min per sample) relatively large tissue volumes, the damaging consequences of mechanical sectioning were avoided.…”

Imaging in real and reciprocal space at the Diamond beamline I13

“…More details can be found elsewhere 1,4 . Currently bio-medical and engineering/materials science applications are the most popular, while geo-physical (see figure 3) experiments have also been carried out with great success [8][9][10][11] . Mainly pink beam is used with filtering towards higher photon energies for materials science experiments.…”