Intracranial aneurysms (IA) represent focal dilatation in a cerebral artery due to weakness in the intima layer.
Unruptured intracranial aneurysms (UIA) have a prevalence of 3.2% of general population, being more common above 30 years and a female to male ratio of 3:1. They are either discovered incidentally or may present with visual complain, headache, stroke or cranial nerve palsy. (1)
Rupture of IA leads to devastating subarachnoid hemorrhage (SAH) which has an incidence of 9 per 100 000 person-years and is associated with high morbidity and mortality.(2) Several grading scores have been used to predict development of complication and outcome of SAH such as Hunt and Hess Classification, World Federation of Neurosurgeons (WFNS) grading scale, modified Fisher score and VASOGRADE scale. (3)
Aneurysmal size was the first determinant of rupture risk, where larger aneurysms carry greater probability of rupture. Recent studies have demonstrated that small aneurysms are responsible for 30-40% of all SAH. Other aneurysm characteristics as neck diameter, aneurysm width, height, parent artery diameter, aspect ratio (AR) and size ratio play a major role in prediction of rupture. (4)
IAs can be classified according to rupture status, location, size and type (saccular, fusiform, dissecting and blister aneurysms) (5)
Detection of IAs done using CT angiography or magnetic resonance angiography, however digital subtraction angiography (DSA) remains the gold standard imaging modality (6)