@Isaiah_40_31 Well, the thing is very simple:
- CT (CTA, CTV) gives “static”, momentarily multiplanar picture. The cannula is usually inserted into the arm’s vein (for CTA/CTV or typical “CT with contrast” where contrast is delivered into the blood circulatory system).
- Cerebral angiogram/venogram is performed using fluoroscopy which is like an x-ray video camera filming the flow. The catheter is navigated often through the groin, arm, or rarely directly through IJV and multiple other procedures can be performed at the same time, like deploying a stent, removing some tromb (in certain cases) etc as the catheter is good for delivering fluids (contrast) and/or some basic tools to the specific target spot (while cannula is for purely fluid delivery (like IV), including the contrast).
See imaging section in the FAQ for more details of each imaging modality and it’s capabilities