DSA (angiography)
A four-vessel angiogram (bilateral common carotid and bilateral vertebral artery injections) demonstrates no cerebral parenchymal perfusion.
The vertebral arteries (left frontal, right lateral) before entering the dura, only giving off small radicular and muscular branches.
Similarly, common carotid artery injections only opacify external carotid artery branches. The internal carotid artery tapers to occlusion in the cervical portion with no contrast seen in the supraclinoid portion or any of the terminal branches.
Note, a retinal blush is seen late in the run. This is probably due to meningeal collaterals. However, even if this is from the internal carotid artery, as the orbit is extradural, this finding does not preclude the diagnosis of br