 Images are limited by patient motion. SWI images are nondiagnosticProminent areas of diffusion restriction are seen in the area of the right trigone in similar configuration to the most recent outside MRI. There is a likely partially embolized AVM in this location, and may represent residual blood products and/or evolving ischemia. There is minimal extension in the right posterior body of the corpus callosum. Surrounding more extensive T2/FLAIR hyperintensity overall has progressed since the prior exam. In the posterior right temporal and occipital lobes, there was previously a vasogenic pattern of edema, which has improved with only minimal residual vasogenic edema remaining in the lateral posterior right temporal lobe. There is persistent transcortical involvement of the anteromedial right occipital lobe by FLAIR abnormality.There has been progression of other more anterior areas of FLAIR abnormality. For example, there were a few subtle foci of FLAIR hyperintensity in the periventricular white matter along the right temporal horn, which is now effaced by confluent signal abnormality. There are also now globular areas of FLAIR abnormality in the mesial right temporal lobe, including involvement of the right hippocampus with gyral expansion. There is greater medial and cranial extension of abnormal signal, along the medial right thalamus and right corona radiata. Additional areas of diffusion restriction with T2/FLAIR hyperintensity are seen along the right lateral margin of the anterior third ventricle just adjacent to the right foramen of Monro. There is resultant focal mass effect with narrowing of the third ventricle, not present on the outside exams. There is more subtle diffusion hyperintensity along the periventricular white matter of midbody of the lateral ventricles along the corona radiata in areas of somewhat oval appearing T2/FLAIR abnormality without convincing ADC hypointensity, likely relating to evolving prior subacute infarcts.There is a slightly more conspicuous area in the right superior vermis, and there is now discontiguous involvement of the more inferior vermis, as well as the right lateral periventricular white matter along the fourth ventricle. The inferior vermian involvement results in mass effect on the fourth ventricle, which is now partially effaced. Retrospectively, there may have been a small early focus of FLAIR hyperintensity along the inferior vermis on the most recent outside MR images.Compared to recent CTs, there is stable localized mass effect including upon the posterior right lateral ventricle. However, mass effect is progressed since the prior outside exams. Midline shift to the left is similar at 5-6 mm, but again slightly progressed since outside exams. There are stable tubular areas of intrinsic T1 hyperintensity in the medial aspect of the right parietal lobe in the area of the AVM which may relate to embolization material or blood products. Right temporal horn was noted to be patent on the most recent outside CT, but is now completely effaced. There is additional confluent periventricular signal consistent with transependymal CSF flow. Although there is likely underlying moderate age-related volume loss, there is increased lateral ventricular size since outside exams, consistent with mild-moderate hydrocephalus.The basal cisterns remain patent. There are scattered punctate foci and confluent areas of abnormal T2/FLAIR hyperintensity within the periventricular and subcortical white matter, which appear somewhat increased in number since the prior exams and may represent interval non-acute small vessel ischemic changes. No extra-axial fluid collection is identified.Normal flow-voids are demonstrated in the major intracranial vascular structures. There is incidental empty sella. The remainder of the midline structures and craniocervical junction are within normal limits. There is a large left maxillary sinus mucosal retention cyst.The intracranial internal carotid arteries are normal in course and caliber. There is a hypoplastic right A1 segment. The middle and anterior cerebral arteries are otherwise unremarkable. There is a mildly hypoplastic left P1 segment. The vertebral arteries, basilar artery, and posterior cerebral arteries are otherwise normal in course and caliber. There is no evidence of flow-limiting stenosis or aneurysm.The area of the right parietal AVM appears to be fed from branches of the right posterior cerebral artery. There may be small veins draining the area of the AVM towards the atrium of the right lateral ventricle in the vicinity of the choroid plexus glomus.
1. Limited exam secondary to patient motion and lack of contrast. Areas of diffusion restriction centrally in the region of the right parietal AVM, which may represent chronic blood products. Although decreased vasogenic pattern of edema along especially posterolateral margins of AVM, there has been progression of more anterior and medial extension of abnormal signal involving the right temporal lobe, with now complete effacement of the right temporal horn. Given outside imaging appearance, this most likely represent areas of evolving cytotoxic edema from infarct, with possible venous as well as small arterial components.2. Other scattered areas of probable evolving possibly embolic infarct, including the right superior vermis, inferior vermis, corona radiata bilaterally, and along right lateral margin of anterior third ventricle.3. Midline shift and localized mass effect appears similar to that of the recent CTs, but are progressed from outside imaging including increased effacement of the posterior right lateral ventricle and complete effacement of right temporal horn. Increased mass effect on the anterior third ventricle and now partially effaced fourth ventricle by new and evolving areas of probable infarct. Increased lateral ventricular caliber with transependymal edema. Close continued follow-up of ventricular size is recommended.4. MRA demonstrates possible arterial feeders from the right PCA to the right parietal AVM. There is questioned subtle venous drainage towards the right atrial choroid plexus.