 MRI Brain:There are multiple areas of restricted diffusion involving the bilateral occipital lobes, bilateral cerebellar hemispheres, cerebellar vermis, the pons, midbrain and left anteromedial thalamus. There is also prominent T2/FLAIR signal abnormality in these regions indicating more acute to subacute infarcts. There is no evidence of frank hemorrhage, midline shift or herniation. There is no evidence of hydrocephalus or basilar cistern effacement.There is encephalomalacia and hemosiderin staining involving the left occipital region, precentral gyrus and inferomedial left frontal lobe, compatible with prior infarcts. Additional moderate periventricular and subcortical white matter T2/FLAIR hyperintensity is nonspecific but likely related to small vessel ischemic disease.Postsurgical changes are again seen in the region of the sphenoid bone and sella, which appear stable from prior studies. The third ventricle appears distorted but is unchanged. The pituitary gland is not identified. There is some signal loss on the susceptibility weighted images involving the right midbrain and right sella which appears similar to the prior exam from 2010. The right middle cerebral peduncle is distorted and narrowed which was present in 2010. The optic chiasm is distorted. There is mild mucosal thickening involving the ethmoid air cells.MRA Brain: There is occlusion of much of the posterior circulation including the bilateral V4 segments just distal to the PICA origins and involving the entire basilar artery. In addition, AICA, SCA and PCA arteries are non-visualized. The bilateral PComAs are also not visualized. The right A1 segment is hypoplastic. There is atherosclerotic irregularity of the cavernous portion of the right greater than left internal carotid arteries.MRA neck:Redemonstrated is high grade stenosis of the left vertebral artery at its origin which is unchanged compared to the prior exam. There is also some mild irregularity of the cervical portion of the left vertebral artery. There is origin of the left common carotid artery from the brachiocephalic artery. There is opacification of the aortic arch, great vessels from the aortic arch and carotid arteries and vertebral arteries. On the basis of NASCET criteria there is no significant stenosis at the carotid bifurcations. There are atherosclerotic calcifications of the origins of the vertebral arteries bilaterally. Additional atherosclerotic calcifications are seen involving the aorta and its proximal branches. There is a small left pleural effusion and nonspecific ground glass opacity versus motion artifact in the bilateral lung apices.
1.Large posterior circulation infarctions involving the bilateral cerebellar and occipital regions with sulcal effacement and edema indicating a more subacute character to the infarcts. There are infarcts also involving the pons, midbrain and left basal ganglia.2.On MRA, there is complete occlusion of the bilateral V4 segments beyond the PICA arteries as well as the entire basilar artery. The AICA, SCA, PCA and PComAa are also non-visualized.3.Moderate chronic likely small vessel ischemic disease and chronic left pre-central gyrus, left anteromedial inferior frontal lobe, and left occipital lobe infarcts.