 Recent years,three-dimensional time-of-flight MRA 3D-TOF-MRA has become a useful, contrast-free method for observing intracranial vessels and is widely utilized as a screening examination for intracranial aneurysms. The studies available in Medline show mixed results.Some of these studies just included MRIMRA in the analysis, which have a high rate of false-positives and are unreliable, and some were lack of control ruptured aneurysm, precise numbers of false-positive results, standard images process and review, or corroborative IADSA in some patients. Furthermore, most previous studies included small sample size with aneurysm detection at 0.5-T or 1.5-T MR. Thus, these results have been inconclusive because of certain pitfalls in these studies. 