Aneurysms are incidentally detected when brain imaging is done for indications other than subarachnoid hemorrhage. The most common indication for brain MRI/MR Angiogram is stroke. It is also done in people who have a high risk of getting brain stroke in future (on account of risk factors and family history).
In our case, a 45-year old presented with recurrent episodes of speech impairment. Brain MRI was normal. However, MR Angiogram showed a 4 mm size saccular aneurysm arising from M2 segment of left middle cerebral artery (MCA).
The incidence of incidental saccular aneurysms on brain MR Angiogram has been found to be 1.8%. It is more common in women than men. The commonest location is MCA bifurcation (about 35% of all incidental aneurysms) and the mean size is 4 mm.
As there is a risk of aneurysm rupture in future, treatment should be advised to those detected with incidental aneurysms. Treatment options include clipping and coiling.