Presentation
Defective vision in right eye for the past 2 days.
Patient Data
Brain
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.
Orbits
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.
Conclusion
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.