15 year-old female. SRS planning. AVM. Enhanced MRI brain:Diffusion-weighted images are negative for acute ischemic stroke.MRI sequences demonstrate a chronic hemorrhage in the right thalamus measuring 7-mm in AP axis and 18.6-mm in transverse axis (axial flair and T2-weighted image 9). There is no evidence of any residual surrounding edema or encephalomalacia. This is at the site of previously known right thalamic hematoma and confirmed angiographically of presence of an arteriovenous malformation. Prominent draining vein of the AVM is noted to extend from the hematoma into the perimesencephalic cistern on the right.There are a few punctate foci of subcortical increased signal intensity in the right frontal lobe of unknown clinical significance.A linear increased signal intensity extends from inner table of the skull into the right lateral ventricle along the track of right sided ventricular catheter.There is prominence of cortical sulci for patient's stated age of 17 which although may be at the upper limits of normal remote possibility of volume loss cannot be report. On post infusion images within the area of hemosiderin deposition in the right thalamus there is evidence of enhancement which measures approximately 17.4 mm in transverse axis and 7.5-mm in AP axis which are measured on axial post infusion image 12. On coronal reformatted post infusion image 13 a subtle area of enhancement measures approximately 11.4 x 16.4-mm.There is no evidence of any additional area of abnormal enhancement the brain parenchyma or leptomeninges.MRA of intracranial circulation:Utilizing an independent workstation 3-D reformatted images of intracranial vascular structures were made.Bilateral internal carotid arteries, anterior cerebral arteries and middle cerebral arteries and their branches are unremarkable.Normal appearing bilateral intracranial vertebral arteries, prominent left pica artery. There is fenestration of basilar artery in its proximal portion. Basilar artery is otherwise unremarkable. There is unremarkable bilateral posterior cerebral arteries and superior cerebellar arteries. Please review report of dedicated cerebral angiogram for arterial supply and venous drainage of the AVM.There is minimal increased vascularity in the region of patient's known right thalamic AVM. This examination cannot assess for vascular pedicle to the AVM due to extreme small size feeding pedicles to this a small AVM.12 cc of Omniscan was administered for above study.
1.MRI examination of brain demonstrate hemosiderin deposition in the right thalamus at the site of prior hemorrhage. Post infusion images demonstrate an enhancing arteriovenous malformation in this location with draining vein extending into the right perimesencephalic cistern. Please see above measurement for the size of the enhancing AVM.2.Essentially unremarkable MRA of intracranial circulation. The very small size of AVM and its feeding branches are beyond the resolution of MRA. Please review report of patient's prior dedicated cerebral angiogram for feeding pedicles and draining venous system of the AVM. 