title: Computed tomography angiography in abdominal aortic endoleaks: what is the optimal protocol?
abstract: OBJECTIVE
  To evaluate the roles of noncontrast and delayed phases of computed tomography angiography (CTA) for optimization of the CTA protocol in endoleak detection.
  
  
  METHODS
  CTAs of patients who underwent abdominal aortic endovascular stent-graft placement were retrospectively reviewed. CTA comprised noncontrast, arterial, and delayed phase (2 minutes postcontrast). The arterial phase was compared with a combined arterial and delayed phase and followed by the noncontrast phase to see whether additional information was obtained.
  
  
  RESULTS
  Thirty-eight CTA studies demonstrated endoleak. In 30 studies (79%; 95%CI 64% to 89%), endoleak was detected in the arterial phase. Eight studies (21%; 95%CI 11% to 36%) demonstrated an endoleak only in the delayed phase. No additional information was obtained in the noncontrast phase when compared with a combined reading of the arterial and delayed phases (95%CI 0% to 9%).
  
  
  CONCLUSIONS
  Delayed-phase imaging is necessary for endoleak detection and obviates a noncontrast phase. Identical parameters should be used for arterial and delayed phases.
authors.affiliation: Department of Medical Imaging, University Health Network and Mount Sinai Hospital, University of Toronto, Toronto, ON.
authors.forename: John M
authors.initials: JM
authors.lastname: Kirby
authors.forename: Kartik S
authors.initials: KS
authors.lastname: Jhaveri
authors.forename: John R
authors.initials: JR
authors.lastname: Kachura
mesh_terms: D001012:Aorta, Abdominal / Q000601:surgery*; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D001027:Aortography / Q000379:methods*; D002985:Clinical Protocols; D006801:Humans; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D015607:Stents; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*