Fig. 2.

Aneurysm volume was calculated using a flat-panel detector (Artis Q BA Twin; Siemens AG, Forchheim, Germany). First, using the preoperative aneurysm volume as the baseline, aneurysm volume 6 months after surgery was calculated as a percentage of that volume. Next, patients whose aneurysm obliteration was judged to be 95% or higher at 1 year after surgery, i.e. Grade C or Grade D obliteration on the OKM grading scale, were classified as the good obliteration group, and those whose aneurysm occlusion was judged to be less than 95% at 1 year after surgery, i.e. Grade A or Grade B obliteration on the OKM grading scale, were classified as the poor obliteration group.