 Brain MRI:There is a focus of restricted diffusion within the right midbrain with associated T2 signal abnormality consistent with an acute infarct. An additional focus of subtle diffusion hyperintensity in the left posterior frontal corona radiata may also represent an additional focus of subacute ischemia. There is no associated susceptibility artifact to suggest hemorrhage. Encephalomalacia within the right occipital lobe is consistent with a prior right PCA territory infarct. T1 hyperintensity in this region is compatible with laminar necrosis. Periventricular and subcortical white matter abnormal T2 signal is consistent with mild chronic small vessel ischemic disease. The ventricles and sulci are normal in size. The cerebellar tonsils are in normal position. There are no masses, mass effect, or midline shift. The pituitary gland is normal in size. There are no extraaxial fluid collections or subdural hematomas. The paranasal sinuses and mastoid air cells are clear. A 1.6 x 1.4 cm intermediate signal, round lesion within the midline slightly anterior scalp may represent a sebaceous cyst or epidermal inclusion cyst; correlate with physical exam.Brain MRA: There is antegrade flow within the distal bilateral vertebral arteries with right dominance and the left vertebral artery terminating as the left PICA. Antegrade flow is identified within the basilar artery with fetal morphology of the bilateral posterior cerebral arteries. There is tortuosity at the level of A1/A2 junction and the right A1 segment is not well seen, which is favored to be hypoplastic. Antegrade flow is noted within the middle cerebral arteries and the posterior cerebral arteries. No arterial aneurysmal dilatation is identified. No arteriovenous malformations are identified.Neck MRA:MRA of the neck is suboptimal in quality but there is no significant stenosis of the external or internal carotid arteries. The vertebral artery origins are poorly evaluated, however, the vertebral arteries distally are patent.
1. Acute infarct within the right midbrain. Possible additional acute to subacute punctate focus of infarct in the left frontal corona radiata.2. Chronic right PCA territory infarct with encephalomalacia within the right occipital lobe.3. Poor visualization of the right A1 segment, which is favored to be hypoplastic. Otherwise, patent intracranial arterial vasculature with bilateral fetal morphology of the PCA's and right vertebral dominance. 4. Suboptimal MRA of the neck with grossly patent vessels within the limitations of the study. The origins of the vertebral arteries are poorly assessed, though patent distally. If further evaluation is warranted, CTA of the neck may be considered.