Assessment of different contrast preparations for micro-computed tomographic microangiographic assessment of canine cadaveric hindlimbs

Abstract

Reliable microvascular identification and quantitative vascular assessment via Micro-CT collection of intraosseous measurements has not been reported in dogs. The aim of this study was to identify the ideal preparation (Criteria: perfusability, radiodensity and homogeneity) for quantitative assessment of canine intraosseous microvasculature. Materials/Methods: Cadaveric specimens were perfused initially with resin preparations [Resin Study: Barium+Resin (BS+R), Barium, Acetone+Resin (BSA+R), Barium Slurry+Resin (BSS+R), and Barium Slurry, Acetone+Resin (BSSA+R)]. BSS+R was then compared with Barium+Saline (BSS) and Barium+Gelatine (BSG) [Comparative Study] using micro-CT via mean radiodensity and Coefficient of Variation (n=20) [vessels >1mm2, 0.3mm2-1mm2 and <0.2mm2] and intraosseous vessel diameter (<200µm) and distribution within the femur, tibia and patella (n=12). Results: Resin Study: BSS+R identified a greater proportion and number of small intraosseous vessels <100µm with a similar mean radiodensity and homogeneity across all vessel sizes. All test preparations were superior to the control (BS+R). The addition of saline, acetone or both improved vessel perfusion. The homogeneity of all preparations was poor with significant variation. Comparative Study: BSS and BSG exhibited larger mean radiodensity compared with BSS+R (P<0.001) at all vessel sizes. BSG produced the most homogenous preparation. All preparations identified vessels to two scan voxels in diameter. BSS exhibiting the smallest mean vessel diameter, greatest proportion (P<0.001) and number of different vessel diameters <100µm. Conclusions: BSS is the most appropriate suspension for analysis of canine intraosseous microvasculature resulting in a significantly more accurate and detailed quantitative microvascular analysis. Resin preparations performed poorly within all characteristics and were inferior to both BSS and BSG. No resin preparation produced a homogeneous suspension in any vessel size.