Abstract
Relatively small unruptured intracranial aneurysms (UIAs) are often managed conservatively. However, rupture of UIA during follow-up occurs occasionally in clinical situations. We retrospectively analyzed cases of ruptured UIAs followed in our institution between 2012 and 2016. Four patients presented with subarachnoid hemorrhage caused by ruptured aneurysms during observation. We calculated the rupture-risk score on the basis of two meta-analyses previously reported. However, these were not effective to estimate the rupture risk of relatively small aneurysms in these cases. Meanwhile, aneurysmal growth was detected in all the cases, which also had at least one risk factor for aneurysm growth. Thus, increase in aneurysm size might be an indicator of rupture, and a slight growth in size should be carefully and seriously considered as a risk factor of rupture to prevent the rupture of small aneurysms.
