Errata: Imaging and Quantitative Assessment of Long Bone Vascularization in the Adult Rat Using Microcomputed Tomography

Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent

“…Finally, it should be noted that because the available energy of X-rays is limited to near the zirconium dioxide k-edge, this method would be unsuitable for specimens that need high-energy X-rays far beyond the zirconium dioxide k-edge, including a thick wall of dense compact bone and bone-implant interfaces. 19,20,47 In conclusion, we have established the feasibility of the combined technique of sSRCT and ZrCA vascular casting in quantitative 3D imaging of angiogenesis and bone repair. Its application to early-stage bone repair in rat cortical drill-hole defects could quantify the impact of mechanical stimuli on vascular ingrowth and bone repair, demonstrating the potential of the present imaging method for the enhanced understanding of angiogenesis and its involvement in bone repair.…”

“…On the other hand, taking advantage of the high light intensity, practically no beam-hardening artifacts, and a high signal-to-noise ratio, synchrotron radiation mCT allows for the quantitative 3D assessment of vascular and bone structures with commonly used contrast agents. 15,19,20 However, contrast enhancement of vasculature could be uneven, especially in non-tree-like microvascular beds, owing to incomplete perfusion as well as inhomogeneous dispersion, settling, or clumping of contrast materials during infusion. 27 Given that vascular image intensity is spatially heterogeneous and not so very different locally from bone image intensity, segmentation into microvasculature and bone is not straightforward even by synchrotron radiation mCT.…”

“…15,19,20 Monochromaticity of synchrotron light also allows measuring apparent mineralization, 21,22 serving as a metric of bone integrity. On the other hand, image registration and subtraction procedures for the two mCT scan sets of decalcified and undecalcified bone specimens containing a vascular contrast-casting agent have been proposed as a potential technique for precise image segmentation into vasculature and bone.…”

Assessment of bone vascularization and its role in bone remodeling

“…Using a similar approach with Scanco mCT devices (VivaCT and mCT40 Scanco Medical AG, Basserdorf, Switzerland), we analyzed the influence of both spatial resolution and threshold on trabecular bone vascularization in barium sulfate-infused rat tibiae after decalcification and found significant positive correlations between histology and mCT results. 64 Synchrotron radiation mCT imaging provided better spatial resolution compared with conventional mCT and did not require sample decalcification, thus allowing to visualize vessels in three-dimensions and analyze their location in relation to the bone surfaces. 61 Using an IMAGEJ-based software, we completed our analysis on histological sections by measuring the mean distance between vessels and the boneforming surfaces (identified by the presence of osteoid) according to the vessel size.…”

The effect of erythropoietin on bone

“…In the author's opinion, the biggest advantage of quantitative CT compared with histological analysis is that the entire volume of interest is analyzed rather than multiple two-dimensional samples, and that the analysis is semi-automatic and therefore less subjective. Recent advances in µCT protocols also enabled the assessment of the secondary outcome measure in Paper 1, vascularization (Fei et al 2010). However, that protocol has not been implemented at our institution so far.…”