CT Brain
No intracranial haemorrhage. Hyperdense thrombus within the left intracranial ICA and M1 segment. Decreased attenuation of the left caudate and lentiform nucleus and decreased grey-white differentiation in the left insula. Ventricular size is normal.
CTA COW and perfusion studies (not shown)
Filling defect is demonstrated throughout the entire left intracranial ICA extending into the left M1. The M1 is hyperdense on non contrast images. The cervical ICA opacifies normally from the CCA bifurcation until its distal portion where tapering of contrast opacification is seen before the vessel enters the petrous temporal bone. No dissection flap is identified.
Contrast opacification of the left M2 (inferior branch)-M4 segments is demonstrated presumably via collateral circulation. These vessels are relatively hypoperfused compared with the contralateral vessels.
There is retrograde filling of the left ACA via the circle of willis. The left CCA and ECA opacify normally.
Perfusion studies demonstrate large area of decreased CBF and CBV, and increased Tmax and MTT in the left MCA territory. This is largely a matched defect with an estimated perfusion mismatch of 124 ml.