J Cerebrovasc Endovasc Neurosurg.  2017 Mar;19(1):44-47. 10.7461/jcen.2017.19.1.44.

Discrepancy between Angiography and Operative Findings of Small Side Wall Aneurysms in Atherosclerotic Parent Arteries

  • 1Department of Neurosurgery, Inje University Seoul Paik Hospital, Seoul, Korea. lessordi@naver.com


Preoperative evaluation of precise aneurysmal geometry is important for the treatment of intracranial aneurysms. We present two cases of unclippable side wall aneurysms due to their extremely low dome height, which appeared as saccular in the preoperative image because of a comparatively narrow atherosclerotic parent arterial lumen. In both cases, a calcified vessel wall was noted preoperatively. Lack of a definitive neck and abrupt discrepancy between the fragile aneurysmal wall and the atherosclerotic parent arterial wall was confirmed intraoperatively in both cases. This study describes an illustrative mechanism for the finding with emphasis on the importance of its preoperative diagnosis. Intracranial atherosclerosis associated with small side walled aneurysms may lead to overestimation of aneurysm height on preoperative imaging of the intravascular compartment.


Aneurysm; Angiography; Atherosclerosis; Diagnosis

MeSH Terms

Intracranial Aneurysm
Intracranial Arteriosclerosis


  • Fig. 1 (A) Brain computed tomography of a 64-year-old male presenting with severe headache, shows multiple calcification on the bilateral cavernous internal carotid artery and middle cerebral artery. (B) Three-dimensional angiography reveals 3.5 mm sized saccular aneurysm at the internal carotid artery dorsal side (white arrow) and a 3 mm sized aneurysm at the lateral side (black arrow). (C) In microscopic view, an unruptured aneurysm with very shallow dome height is noticed in the atherosclerotic parent artery.

  • Fig. 2 (A) Three-dimensional angiography shows a saccular aneurysm with a 5 mm maximal diameter and 4 mm height at the M1 segment of the right middle cerebral artery (MCA) in a patient with headache. (B) Intraoperatively, the aneurysm has a very shallow aneurysmal height and shows a hemispheric appearance without any definitive neck, in contrast to its initial saccular angiographic finding. The parent artery is severely atherosclerotic along its entire length. Several other hemispheric bulges with thin aneurysmal wall are noted on the ipsilateral MCA. (C) Postoperative computed tomography shows asymptomatic a minimal subdural hematoma on the contralateral side. Diffuse calcification is present along the right middle cerebral and anterior cerebral artery.

  • Fig. 3 An angiographic saccular aneurysm is confirmed as a blister-like small aneurysm with hemispheric dome on surgical exploration. The discrepancy in the outer and inner walls of the parent artery is due to atherosclerotic plaque, which gave it a higher neck to dome ratio on angiography than its real size.


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