title: Use of CT angiography to classify endoleaks after endovascular repair of abdominal aortic aneurysms.
abstract: OBJECTIVE
  Accurate endoleak detection and classification is critical for the follow-up of patients who have undergone endovascular aneurysm repair (EVAR). This determination is often made with computed tomography angiography (CTA). This investigation was performed to determine the accuracy of CTA in the classification of endoleaks in patients who have undergone EVAR.
  
  
  METHODS
  Thirty-six patients with endoleaks underwent both CTA and conventional contrast digital subtraction angiography (DSA) to determine endoleak etiology. Two independent radiologists determined the source of the endoleak based on a retrospective review of the CTA. The results of the CTA-based endoleak classification were compared to the reference standard, contrast DSA.
  
  
  RESULTS
  There was agreement regarding endoleak classification between CTA and DSA on 86% of the patients (31 of 36 patients). Correlation between the CTA reading of the two readers was 94% (34 of 36 patients), yielding a kappa statistic of 0.8. In three patients, the CTA reading incorrectly classified endoleaks as type 2 when the endoleaks were actually type 1 endoleaks on DSA. One patient was incorrectly classified as having a type 1 endoleak on CTA when it was a type 2 endoleak on DSA. Finally, one patient had a type 1 endoleak on DSA that was incorrectly classified as a type 3 endoleak on CTA. The change in CTA endoleak classification based on the DSA resulted in a significant change in patient management in four of the 36 patients (11%).
  
  
  CONCLUSIONS
  Endoleak classification based on CTA correlates fairly well with DSA findings. However, optimal endoleak management requires performance of selective angiograms with DSA to classify endoleaks that are detected on CTA.
authors.affiliation: Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, 19104, USA. stav@uphs.upenn.edu
authors.forename: S William
authors.initials: SW
authors.lastname: Stavropoulos
authors.forename: Timothy W I
authors.initials: TW
authors.lastname: Clark
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Carpenter
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Fairman
authors.forename: Harold
authors.initials: H
authors.lastname: Litt
authors.forename: Omaida C
authors.initials: OC
authors.lastname: Velazquez
authors.forename: Erik
authors.initials: E
authors.lastname: Insko
authors.forename: Michael
authors.initials: M
authors.lastname: Farner
authors.forename: Richard A
authors.initials: RA
authors.lastname: Baum
mesh_terms: D000792:Angiography / Q000379:methods*; D015901:Angiography, Digital Subtraction; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol; D008297:Male; D011183:Postoperative Complications / Q000145:classification / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol