MRI
Axial T2
Axial Echo planar
Axial T1
Axial T1 C+
Axial MRA
A thrombosed mixed fusiform/saccular giant aneurysm, measuring up to 4 x 5.2 cm, is centred within the left Sylvian fissure, splaying the major left MCA branches.
The inferior irregular non-thrombosed portion of the aneurysm, measuring 10 mm diameter, arises from a posterior branch of the left MCA M2 segment.
This communicates directly with a 5 mm diameter serpiginous channel, which winds through the thrombosed body of the aneurysm to terminate at the dome's superomedial margin, apparently in direct communication with a tiny left parietal branch.
Despite the aneurysm's size, there is only mild to moderate mass effect and surrounding vasogenic oedema, adjacent sulcal effacement and up to 4-5 mm midline shift to the right.
Multiple T2 hyperintense lesions are scattered elsewhere through the frontoparietal white matter of both cerebral hemispheres.
Appearances are in keeping with chronic small vessel ischaemic change, relatively excessive for age.