Basilar top and left middle cerebral artery aneurysm

Case contributed by Dr Varun Babu


Defective vision in right eye for the past 2 days.

Patient Data

Age: 60 years
Gender: Male


Chronic infarction and gliosis of left occipital lobe (PCA territory) and left cerebellar hemisphere (PICA territory).

No focal neuroparenchymal lesion. No acute infarct. No extra axial or intra axial hemorrhage. Basal ganglia and thalami are normal. Ventricles and basal cisterns are normal. Brain stem is normal. No sellar lesion. Paranasal sinuses are normal.

Cerebral angiogram

Revealed a basilar top aneurysm of maximal size 6.5 x 7.0 x 6.1 mm (TR x AP x CC) pointing posterior and just to left of midline.

2.9 x 2.2 x 3.1 mm (TR x AP x CC) saccular aneurysm blind ending and lateral pointing at left MCA trifurcation. Rest of the cerebral vasculature is normal.


T2 hyperintense signal seen within retroglobular right optic nerve. Normal contour and morphology of both globes. Extra ocular muscles are normal.  Normal left optic nerve and perioptic CSF space. Normal optic chiasm. Intraocular fat is preserved. Orbital apex is normal.  No cavernous sinus thrombosis. No dural sinus thrombosis.


  • Chronic left posterior circulation infarction involving left occipital lobe and left PICA territory cerebellar hemisphere. No acute infarction.

  • Features of right optic neuritis.

  • No sellar / suprasellar mass lesion.

  • Incidentally detected basilar top and left MCA trifurcation aneurysms. No arterial dissection or focal stenosis.  


Annotated depiction of positive findings.

Case Discussion

On further probing this patient revealed he had a past history of stroke for which imaging was done, however, no aneurysms were documented. It was difficult to miss the basilar top aneurysm in this case as it was staring right in the center of the axial cross-sections. The left middle cerebral artery aneurysm is a much more difficult pick and was identified only on the second reading. 

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Case information

rID: 61965
Published: 26th Jul 2018
Last edited: 9th May 2021
Inclusion in quiz mode: Included
Institution: Vivid Diagnostic Centre

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