Cerebral MR angiography is a noninvasive angiographic technique based on either time-of-flight or phase-contrast method. The 3D-TOF method widely used has certain disaduantages: its poor visualization of slow flow vessels and distal vasculature in a thick imaging slab due to the effect of progressive saturation of inflow spines. To assess the effectiveness of MR angiography in comparison with that of digital subsraction angiography, we investigated the MRA data on 14 cases. A 1.5T system (Signa Advantage ; GE Medical System) was used in this study. The subjects were 8 males and 6 females. The compatibilities between the findings of MRA and DSA were 79% and the sensitivity of cerebral aneurysms was 70%. Because the contrast of the vessels comes from changes in blood flow, artifactual signal loss can be caused by slight changes in normal blood streams such as eddy flow or decrease in flow velocity. In conclusion, MR angiography is considered to be a safe and useful screening technique for the detection of aneurysms. However, the performance of the modern MRA system is limited because of the presence of false aneurysms.