Time is brain!   So you don’t have time to struggle w/that stroke alert head CT.   Here’s are the FIVE main the CT findings in acute stroke.   --Hyperdense artery sign Occurs when you see the thrombus in the artery. Thrombus appears hyperdense bc clot is denser than normal flowing blood—& CT is just a measure of density.   --Blurred basal ganglia/lentiform nucleus. Usually this region is a triangle of low density white matter surrounding the high density lentiform nucleus In an acute infarct, this triangle becomes blurred, bc the lentiform nucleus becomes edematous & similar in density to white matter.   --Hypodense regions of brain When O2 & ATP run out, Na/K pump stops working Osmotic gradient causes Na & H20 rush into the cell. More water in the cell = lower density.  For every 1% increase in H20 there is a 2.5 HU decrease in density Means damage is irreversible   --Insular ribbon Insula is an internal MCA watershed between the lenticulostriates & M2 sylvian branches Infarcts relatively early with low blood supply & becomes a low density ribbon   --Sulcal effacement Normally, brain has sulci that look like ice cracks/crevasses along its surface. As water accumulates in dead cells, swelling occurs, & the crevasses are effaced by the swollen brain   So now you know the 5 main signs of acute infarct on CT—remember, if you see these five, soon that brain won’t be alive!