Evaluation of Blister-Like Aneurysms Using Optical Coherence Tomography

Digital subtraction angiography of a woman in her 50s presenting with subarachnoid hemorrhage revealed a blister-like aneurysm 1 within the right internal carotid artery (Figure ,A).Subsequent optical coherence tomography (OCT) imaging was performed to elucidate the pathologic features of the aneurysm.The OCT findings demonstrated a thrombus adhering to the inner wall of the aneurysm (Figure ,B).Within the aneurysm wall, the intima, media, and adventitia layers were indistinguishable.Notably, a slender intimal flap was identified at the juncture of the artery and aneurysm walls (Figure ,C).The presence of this intimal flap provides evidence to support the involvement of dissection in the causal mechanism underlying the formation of blister-like aneurysms. 1,2By contrast, a section of the aneurysm exhibited a spherical contour (Figure ,D) while the intima, media, and adventitia layers in the artery wall next to the aneurysm were discernible (Figure ,E). Figure Imaging Features (A) A blister-like aneurysm (arrow).(B) A thrombus (arrow).(C) Indistinguishable layers (asterisk), an intimal flap (white arrow), and the true (star) and false (yellow arrow) lumen.(D) The aneurysm's saccular dilatation.(E) The intima (red arrow), media (yellow arrow), and adventitia (white arrow) in the artery wall.