The Chinese Cerebral Aneurysms Survey is a continuing prospective study to evaluate the effectiveness of unenhanced, three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) with volume rendering (VR) at 3-T in the detection of intracranial aneurysms.

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 MRI/MRA 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.

Since 2007, we have conducted a clinical study to objective detection of intracranial aneurysms in our routine diagnostic work-up of intracranial aneurysms by our neuroradiologists using a standard procedure with 3D-TOF-MRA with VR at 3T. The investigators want to establish the quality data to prospectively compare 3D-TOF-MRA with VR at 3T vs 3D-RDSA in the diagnosis of intracranial aneurysms in a largest cohort of patients and test it accuracy in screening for suspected patients

Inclusion Criteria:

• Suspected or known intracranial aneurysms

Exclusion Criteria:

• Patient's inability to cooperate
• Chronic renal failure patients
• Any patients with a contraindication to MRA examination, such as pacemaker, orbital metallic foreign body, coronary stent, etc.
• Any patients with a contraindication to DSA examination, such as allergic to contrast medium, etc.

We estimated that a sample of 350 patients including 12% dropout rate would be enrolled to determine an accuracy of VR 3D-TOF-MRA versus VR RDSA as reference standard with a 95% confidence interval of 5% (i.e., a standard error of approximately 2.5 %) above and below the expected VR 3D-TOF-MRA accuracy of 95%. A P value of 0.05 was considered to indicate statistical significance.