Computer-aided surgery makes use of a variety of technologies and information sources. The challenge over the past 10 years has been to apply these methods to tissues that deform, as do vessels when relatively rigid flexible objects are introduced into them (Lunderquist rigid guide wire, aortic prosthesis, etc) Three stages of computer-aided endovascular surgery are examined: sizing, planning, and intraoperative assistance. The authors' work shows that an approach based on optimized use of the imaging data acquired during the various observation phases (pre- and intraoperative), involving only lightweight computer equipment that is relatively transparent for the user, makes it possible to provide useful (ie, necessary and sufficient) information at the appropriate moment, in order to aid decision making and enhance the security of endovascular procedures.