There is a left PCA occlusion. When assessing the cerebral vasculuture, make sure you focus on the posterior circulation. The cerebral veins (basal vein of rosenthal) travel close to the PCA, so ensure that you don't accidentally follow a venous structure instead of the PCA.
The often quoted ideal stroke windows are 35 35 , or 40 40. But it is suggested to always window and level yourself based on your visual preferences. Many factors such as monitor grey scale values can affect the final output, so better to rely on a window and level that is comfortable for you in detecting the subtle grey-white differentiation.
Hyperdense M2 - Imaging Sign
The course of the MCA through the Sylvian Fissue, so-called M2 Branches after the triforcation of the M1 segment, can appear hyperdense indicative of clot within the vessel.
This is the distribution of a PCA occlusion. Involvement of the midline posterior falx is often seen.
Ventricular margins can sometimes provide a clue to presence of an infarct. Whenever there is a contour abnormality, consider an infarct and subsequent volume loss as a possible cause.
Insular Ribbon - Imaging Sign
Loss of the grey-white diffrentiation in the external capsule/insula is called the insular ribbon sign that can be lost in acute stroke.