Clinical question: Evaluate for possible aneurysms seen on MRI. Signs and symptoms: Possible aneurysm seen on MRI. CTA of intracranial circulation:Source images, MIP and 3-D reformatted images were obtained.Vertebral basilar system:Patent bilateral intracranial vertebral arteries and bilateral pica branches. Patent basilar artery and its branches and with no pathology.Carotid system:Right internal carotid artery across the skull base and through the cavernous sinus remains normal. Right supraclinoid internal carotid artery is unremarkable. Hypoplastic left A1.Right middle cerebral artery is normal in its M1 segment. There is an aneurysm at the bifurcation of right middle cerebral artery which measures 11.2-mm in transverse axis and 8.5-mm in cranial cephalad axis (coronal reformatted image 120). This aneurysm projects directly laterally and shows uniform enhancement. The aneurysm sac appears to incorporate the distal tip of right middle cerebral artery and the origins of superior and inferior divisions of the right middle cerebral artery. There is no detectable internal defect to suggest presence of clot. The distal branches of right MCA beyond this aneurysm remain normal.The left internal carotid artery across the skull base and in its cavernous component are within normal limits. The left missing or free and its branches are within normal limits. The left A1 is prominent and fills both anterior cerebral arteries through a patent anterior communicating artery. There is slight ectasia of the distal left A1 immediately proximal to its junction to the anterior communicating artery. There is no distinct aneurysm.CTA of the vasculature of the neck:Right common carotid artery, right internal carotid artery and including their origins are normal thereleft common carotid, left external carotid artery and their origins are within normal.Right vertebral artery and including its origin is unremarkable.Left vertebral artery and including its origin is normal.Nonenhanced CT of brain:Focal area of increased density along the superior aspect of the vermis a left paramedian location is again identified. There is no associated mass effect with this finding and no change in its size since prior CT and MRI exam. Findings could represent area of calcification or a cavernoma. On coronal reformatted image number 53 this lesion measures 14.2 times 10.5-mm.Well demarcated high density lesion at the expected level of right MCA bifurcation measures 9.3 x 9.7-mm and is believed to represent an aneurysm. This examination is otherwise essentially unremarkable.60 cc of Omnipaque 350 is administered problem study.
1.Aneurysm of right MCA bifurcation with no internal thrombus. Aneurysm measures 11.2 x 8.5-mm in size and has a direct lateral projection. The aneurysm sac appears to incorporate distal right M1 and the origins of M2 segments of the middle cerebral artery. There is hypoplastic right A1 with minimally ectatic distal left A1 however no distinct aneurysm. The CTA of intracranial circulation is otherwise unremarkable.2.Unremarkable CTA of the vasculature of the neck.3.Stable CT examination of brain with partially thrombosed right MCA aneurysm and focal area of calcification or cavernoma in the superior vermis in left paramedian location.