61-year-old male with an acute ischemic stroke. Is there chronic right carotid occlusion? There are numerous foci of restricted diffusion within a watershed distribution in the right cerebral hemisphere. The largest area is in the right frontoparietal corona radiata. There are a few foci of restricted diffusion in the occipital lobe in the MCA/PCA watershed as well. Many of these areas are associated with increased T2 signal. Additional areas of increased T2 signal within the periventricular and subcortical white matter are not associated with diffusion restriction and are compatible with mild chronic small vessel ischemia. There is a punctate focus of susceptibility effect within the white matter of the right frontal lobe compatible with chronic hemorrhage.The intracranial right ICA flow void is absent related to slow or retrograde flow with the extent of ICA occlusion better seen on the recent CTA. There is no evidence of acute intracranial hemorrhage or mass. There is asymmetric increased enhancement within the right cerebral hemisphere related to collateral blood flow. No abnormal parenchymal enhancement is present. The ventricles and basal cisterns are normal in size and configuration. There is no midline shift or herniation. There is moderate mucosal thickening within the left maxillary sinus and posterior ethmoid air cells on the left. There is partial opacification of the mastoid air cells on the right. The orbits, skull, and scalp soft tissues are grossly unremarkable.On perfusion images the cerebral blood volumes in the right cerebral hemisphere are preserved, and in fact, there are areas with increased blood volume in the right frontal white matter, finding which can be seen with chronic stenosis. There is prolongation of mean transit time throughout the right cerebral hemisphere. Cerebral blood flow images also demonstrate areas of increased flow in the right frontal lobe adjacent to the areas of infarct.
1.Multiple foci of acute infarct in the right cerebral hemisphere in a watershed distribution.2.Right internal carotid artery occlusion, extent of which was better delineated on the recent CTA. 3. Preserved cerebral blood volume in the right cerebral hemisphere with areas of elevated cerebral blood volumes in the right cerebral hemisphere compared to the left. These findings can be seen with chronic stenosis/occlusion with preserved perfusion through collaterals. There are foci of acute infarct however indicating acute decompensation of collateral flow or possibly acutely developed complete occlusion on a background of chronic high-grade stenosis.