Table 2.

Methods of assessment of collateral formation and limb perfusion.

Techniques	Results Obtained	Advantages	Disadvantages
Micro-CT	- Anatomical visualization of vasculature circulation - Extent of vasculature formation	- Non-invasive - Reproducible - Repeatable - 3D reconstruction	- Challenging to discriminate arteries from veins - Ionizing radiation
Ex vivo Micro-CT of polymer casted vasculature	- Extent of vasculature formation - Quantification of changes in the microvasculature	- Only arteries - 3D reconstruction	- Invasive - Repeated measurement not possible
X-ray microangiography	- Gross anatomical view of the circulation	- Overview of the vascular anatomy	- Invasive - Technically challenging - Only 2D projection images
Post-mortem X-ray microangiography	- Gross anatomical view of the circulation	- Overview of the vascular anatomy	- Repeated measurement not possible
MRA	- Detecting arterial blood flow - Determine collateral formation - Follow collateral arterial formation	- Repeated measurements possible - 3D reconstructions	- Invasive (vascular access for injecting contrast) - Long scan times
MRI TOF	- Visualizing flow within vessels - Quantitative evaluation of arterial blood flow - Determine collateral formation	- Non-invasive - Repeated measurements possible - 3D reconstructions	- Long scan times
SPECT	-Analyzing perfusion recovery	-Non-invasive -Accurate	-Special facility is needed