Abstract: To explore the role of 64channel multi-detector row CT angiography（MDCTA） volume rendering (VR) and digital subtraction angiography (DSA) in the diagnosis and characterization of intracranial aneurysms. MethodsIn this blind prospective study, 38 patients with suspected intracranial aneurysm underwent both 64channel MDCTA and DSA. VR was adopted to reconstruct images in all cases and some were assisted by the maximum intensity project (MIP) if necessary. The MDCT angiograms were interpreted for the presence, location, size, ratio of the neck to the dome (N/D ratio), and lobularity of the aneurysms and relationship of the aneurysm with the adjacent arterial branches. ResultsA total of 42 aneurysms were detected by DSA in 35 patients and 41 were by CTA, whereas no aneurysms were detected in 3 patients. Compared with DSA, the overall sensitivity, specificity and accuracy of MDCTA on a peraneurysm basis were 95.2%，100% and 89.1%, respectively. Of all 42 aneurysms, 3D-CTA with VR well demonstrated aneurysms and provided useful information including the site, shape, size and spatial relationship to the surrounding vessels and bony structures. In addition, MDCTA was also accurate in determining the N/D ratio of aneurysms, aneurysm lobularity and adjacent arterial branches. ConclusionMDCTA is accurate in the detection and characterization of intracranial aneurysms and can be used as a reliable alternative imaging technique to DSA in selected cases. DSA combined with CTA VR is quite useful for the diagnosis and treatment of intracranial aneurysms.

Key words: Intracranial aneurysms, Tomography, X-ray computed, Image processing, computerassisted, Cerebral angiography