Figure 1.
Cross-sections used in the calculation of vascular density.
Representative cross-sections of the reference region (neck, A–C) and the region of interest (right lower hind limb, D–F). A) Neck region pre-contrast injection. B) Neck region post-contrast injection. C) In red, mask of the region used to quantify the average X-ray absorption in blood (µblood). D) Lower hind limb region pre-contrast injection. E) Lower hind limb post-contrast injection. F) In green, mask of the region used to quantify the average X-ray absorption in muscle (µmuscle). Grey (bone) and black (skin and surroundings of bone) areas were excluded from the evaluation. Numbers represent anatomical structures of interest: 1) Vertebra; 2) Trachea; 3) V. jugularis; 4) Tibia; 5) Fibula; 6) V. poplitea.
Table 1.
Reproducibility of morphometric analysis for large vessels.
Table 2.
Reproducibility of morphometric and densitometric analysis for medium vessels.
Table 3.
Reproducibility of densitometric analysis for medium vessels.
Figure 2.
Robustness results for morphometric analysis of the lower hind limb when 50% and 100% of the standard contrast volume were injected.
All assessed parameters (A) VV/TV, B) VS/TV, C) V.Th, D) V.Sp, E) V.N) exhibited significant differences between half and full dose measurements. ***p<0.001, **p<0.01. N = 7/group.
Figure 3.
Robustness results for densitometric analysis of the lower hind limb.
Average X-ray absorption values in blood (A) and muscle (B) when 0%, 50% and 100% of the standard contrast volume were injected. Significant differences were found between all three cases. C) Vascular density values calculated with the densitometric analysis corresponding to 50% and 100% of the standard contrast volume. No significant differences were found for vascular density, which indicated that it is not influenced by the injected dose of contrast agent. ***p<0.001, **p<0.01. N = 7/group.
Figure 4.
Blood perfusion map of the mouse lower hind limbs 2 days after ligation of right femoral artery, obtained with laser Doppler imaging.
The color bar represents blood flow (or perfusion) levels, from blue (low) to red (high). Note the much lower perfusion levels of the right (ligated) paw compared to the left (control) paw.
Figure 5.
Time course of vascular parameters.
A–E represent parameters calculated for medium vessels from morphometric analysis, while F is calculated for small vessels from densitometric analysis. In morphometric analysis, VV/TV of medium vessels, VS/TV, V.Th, and V.Sp of ligated paws exhibited significant differences on day 2 with respect to pre-surgery sham and control values. In the densitometric analysis, V.D of small vessels of ligated paws also exhibited a significant difference with respect to pre-surgery sham and control values. *p<0.05. N = 12 for ligated group, N = 4 for sham-operated group, and N = 7 for control group (from reproducibility study).
Figure 6.
Results obtained from histological analysis.
A) Vascular density calculated with histological analysis for ligated, sham-operated and control paws. Significant differences were found for ligated paws as compared to the other groups. B) Correlation curve for VV/TV and V.D using histological analysis as reference imaging technique. N = 4/group.
Figure 7.
Results obtained from vascular corrosion cast analysis.
A) Overview of a vascular corrosion cast (without corrosion of hard tissues) of the right lower hind limb, scanned with medium-resolution (10 µm) micro-CT. Blood vessels are represented in red, bone in grey. Numbers represent anatomical structures of interest: 1) Femur; 2) Tibia; 3) Knee joint; 4) Fibula. B) Detail of the lower hind limb vasculature obtained by micro-CT scanning at ultra-high resolution (1.4 µm). Notice that the capillary network can be clearly visualized. C) Correlation curve for VV/TV and V.D using ultra-high resolution micro-CT of vascular corrosion casts as a reference imaging technique.