Possible aneurysm, cavernous malformation or tumor. The patient has ataxia, falls, headaches and MRI abnormality at OSH. Right sided weakness. MRI of the brainNo diffusion weighted abnormalities are appreciated.There is a 42x34x34 mm premedullary and prepontine mass (partially thrombosed aneurysm) with heterogenous signal on T1 and T2 associated with flow voids. Much of the signal is hyperintense on T1WI.The brainstem is displaced and compressed posteriorly by the mass and drapes over the mass. The inferior aspect of the 4th ventricle is narrowed and the foramina of Luschka are distorted. There is mixed signal along the periphery of the mass on SWI phase imaging with some bright signal and some dark signal some of which is opposite in signal on the corresponding magnitude SWI images (suggesting peripheral calcification). The vertebral arteries and basilar artery are contiguous with this mass.A similar signal characteristic well-circumscribe mass is present in the left upper carotid space measuring 16x21x24mm.The temporal horns of the lateral ventricles are dilated. Overall there is mild enlargement of the third ventricle (10 mm width) and lateral ventricles (41mm biventricular diameter at the level of foramina of Monro).There are several supratentorial periventricular and subcortical white matter T2 and FLAIR hyperintense lesions.Normal vascular flow voids are present in the proximal anterior, middle and posterior cerebral arteries as well as the internal cerebral veins and superior sagittal sinus.The 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:There is a partially thrombosed 42x34x34 mm giant aneurysm at the distal left vertebral artery and vertebrobasilar junction. The LVA ends in the aneurysm. The RVA is contiguous with the aneurysm distally and at the V-B junction.There is extracranial origin of the right and left PICAs.There is a 16x21x24mm pseudoaneurysm along the left cervical internal carotid artery at the C1 vertebral body level along the lateral aspect of the left ICAAntegrade 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.The anterior communicating artery is identified and is small in size. The posterior communicating arteries are intact and small.
1.Partially and subacutely thrombosed giant vertebrobasilar aneurysm with calcified wall associated with mass effect on the brain stem and 4th ventricle and mild ventriculomegaly. This aneurysm primarily involves the left vertebral artery but also involves the medial aspect of the distal right vertebral artery. The PICAs have extracranial origin and are well proximal to the aneurysm. PCOMAs appear to be small. Origin of medullary perforators and anterior spinal arteries are not readily appreciated. Conventional angiography may help further assess for these vessel origins.2.Large pseudoaneurysm along the distal left cervical ICA.3.Findings were discussed with Dr Awad.