Brain aneurysm is a focal disease of cerebral wall, characterized by focal weakness and dilation of the wall. The danger of brain aneurysms is in its rupture, which carries a risk of death of around 50% and a risk of permanent deficit over 60% in those who survive. The aneurysm can be either secured or followed. The prediction of aneurysm rupture is of key value for the decision-making process and also during discussion with the patient about possibilities of treating the aneurysm. Today, the information can be mostly based on large population studies, such as the International Study on Unruptured Intracranial Aneurysm – ISUIA. However, the information is inadequate and we need to base the information more on individual characteristics of the patient the prediction based on individual characteristics of the aneurysm.