Aim To evaluate the clinical value of electron beam computer tomography(EBCT) in the diagnosis and follow-up of atherosclerotic aortic aneurysms. Methods A retrospective study was performed during a period of time from January 2002 to December 2004.Sixty-eight patients with atherosclerotic aortic aneurysms were underwent EBCT more than 2 scans.Sixty-eight patients(57 men and 11 women,range from 40～79 years,mean 62.5±9.4 yeras) were diagnosed with atherosclerotic aortic aneurysms.In this group,mean follow-up time was 107 days.EBCT scanner was used with a model of Imatron C-150XP.Contrasted enhanced continuous volume scanning(CVS) was performed.The slice thickness was 6 mm or 3 mm with an acquisition time of 100 milliseconds.The total amount of contrast media(Ultravist 300 or 320,or Ominpaque 300 or 320 g/L) of 80～100 mL was used with the rate of 3.5～4.5 mL/s.The scan delayed time was 18～30 s. Results Sixty-eight patients with atherosclerotic aortic aneurysms were diagnosed.Most of aortic aneurysms location and characters were corresponding to their clinical syndrome.In this group,51 patients were associated with true aneurysms,17 patients were associated with false aneurysms.Most of true aneurysms localized abdominal aorta(p<0.01).False aneurysms mainly localized aortic arch and proximal thoracic aorta(p<0.01).Shuttle aneurysms mainly localized abdominal aorta(p<0.01).Shuttle-cystiform aneurysms of true aneurysm mainly localized descending of thoracic aorta and descending of thoracic aorta and abdominal aorta.Cystiform aneurysms mainly localized aortic arch and proximal thoracic aorta.In this group,47 patients accepted open aortic surgery,11 patients accepted endovascular aortic aneurysm repair,10 patients accepted medical treatments. Conclusions Electron beam CT was a very useful tool for defecting atherosclerotic aortic aneurysms and follow-up.