Reason: 3T Scanner, SRS for AVM March 2013 History: Please evaluate for changes post SRS MRI of the brainAn arteriovenous malformation located adjacent to and posterior medial to the trigone of the left lateral ventricle is less conspicuous on the T2 images relative to the prior exam, however, it is still visible on the SWI and GRE images indicating that it has decreased in size compared to the prior exams. Feeding arteries and draining veins have also decreased in caliber. Post contrast images demonstrate some of the adjacent draining veins. The right basal vein is larger than the left basal vein. This is non-specific, however, and may relate to normal asymmetry, decrease in caliber of the left basal vein with redirection of venous drainage - especially since the straight sinus was reportedly narrowed proximally - or persistent venous drainage for the AVM. The patient has developed some T2 and flair bright signal changes in the adjacent brain parenchyma which has regressed since the prior exam and is associated with encephalomalacia. There is associated contrast enhancement along a small portion of this signal changeIncidental note is made of a left-sided periclival persistent trigeminal arteryThe visualized portions of the paranasal sinuses are clear. The visualized portions of the mastoid air cells are clear. The visualized portions of the orbits are intact.MRA brain:Antegrade flow is present in the distal internal carotid arteries, the distal vertebral arteries, the basilar artery and the proximal anterior, middle and posterior cerebral arteries.There is 3 mm axial dimension arteriovenous malformation located adjacent to and posterior medial to the trigone of the left lateral ventricle. On the 10/6/14 exam it measured 7mm. Its drainage into the vein of Galen is note readily depicted, however, its drainage into the superior sagittal sinus remains visible. The left posterior cerebral artery distal branches near the AVM appear larger than the right posterior cerebral artery distal branches, suggesting supply from the left posterior cerebral artery.Incidental note is made of a left-sided periclival persistent trigeminal artery
1.Continued regression of arteriovenous malformation located adjacent to the trigone of the left lateral ventricle.2.Tissue reaction surrounding the AVM along the adjacent brain parenchyma - likely related to postradiation effect - continues to regress.3.Persistent trigeminal artery.