顱內動脈瘤所引發的蜘蛛網膜下腔出血其致死率相當高，且通常發現時患者情況已十分危急，所幸現今電腦斷層攝影術相當普及，其快速拍攝且低風險的特性剛好適用於此狀況，但醫師在診斷時仍然以二維影像為主，如要重建出三維影像則須將影像於放射科重建，且所重建三維影像無法作即時的操作與瀏覽，如此一來，不僅費時且無充分利用三維影像的優點。本研究為了讓醫師充分利用CT影像，並獲取足夠的術前輔助資訊，因此發展了一顱內動脈瘤手術術前評估系統，提供了腦瘤區域快速判斷的機制讓醫師迅速找出病灶制定方針，並以軟體進行開顱手術模擬，讓醫師不需實際動刀即能觀看開刀後的結果，在手術模擬的最後，本研究運用所開發之半自動對位演算法，進行腦血管擷取，並設計案例驗證其準確性與適用性。Intracranial aneurysm, often caused by subarachnoid hemorrhage, is usually found in a very critical condition and its mortality is quite high. Fortunately, computed tomography is right for catching the image of this disease for its fast shooting and low risk. However, doctors usually do the diagnosis with two-dimensional images. Although three-dimensional images are currently available, they only can be provided by the Department of Radiology, which makes it difficult for doctors to perform real analysis, planning and simulation in a three-dimensional environment. As a result, it is not only time-consuming, but also cannot fully utilize the advantages of three-dimensional images. This study aims to take full advantage of CT images to development an intracranial aneurysm craniotomy system. The proposed system is based on 3D images display and manipulation for the analysis, planning and simulation of craniotomy surgery procedures. A semi-automatic alignment algorithm is developed in this study to retrieve cerebral blood vessels for two sets of CT images, one with contrast medium, while the other not. Doctors can realize the entire surgical process and can obtain as much information as possible before surgery. It can indeed provide substantial help for the preoperative planning of craniotomy surgery.