Aim of this paper is to describe the technical main features that characterize Spiral Computed Tomography (CT) angiography. In particular, the technical features of the three main generations of single, four, and sixteen multislice scanners have been analised. Particular attention have been addressed to scan and reconstruction parameters, and to the geometry of contrast material related to angiographic scan. Guidelines for the different generations of CT scanner have been extracted to give the radiologist a platform for diagnostic questions.