|
FIG 4. A 62-year-old woman presenting with a left CN III palsy due to posterior communicating artery aneurysm.
A, IA-DSA of left common carotid artery, lateral projection. A large left, saccular, posterior communicating artery aneurysm with a discrete narrow neck is seen well.
B, TOF-MIP MRA (100/20/1), similar projection to that of A. Streamlining artifact is seen within the internal carotid artery, and there is signal loss within the aneurysm itself.
C, TOF-3D-isosurface MRA (100/20/1), similar projection to that of A and B. The posterior communicating artery aneurysm (arrow) appears identical to its depiction by IA-DSA.
D, Axial-source TOF image (100/20/1). The true lumen of the posterior communicating artery aneurysm is depicted as high signal, but this is surrounded by concentric mixed signal rims representing intramural thrombus (arrow). The presence of thrombus is not appreciated on the IA-DSA image. The aneurysm is significantly larger than the IA-DSA and postprocessed MRA images suggest.
|