Acquiring appropriate preoperative images is an important step in the treatment of cerebral aneurysms. Despite recent advances in contrast-enhanced CT and MRI, catheter angiography remains the standard of care in preoperative imaging tests for both ruptured and unruptured intracranial aneurysms. Three-dimensional rotational angiography can provide a clear view of vascular structure around the aneurysm in an intuitive manner, including the small perforators. For ruptured aneurysms, the treatment modality(i.e., surgical clipping or endovascular embolization)is usually based on emergent contrast CT and catheter angiography findings. For unruptured aneurysms, integrated assessment involving CT, MRI, and angiography is often useful in multimodal treatment decision making.