title: CT findings of secondary aorto-enteric fistulae.
abstract: OBJECTIVE
  The aim of our study was to review CT findings concerning secondary aorto-enteric fistulae (AEF). In particular, we aimed to evaluate signs of contrast medium extravasation from the aortic graft into the bowel (active bleeding), in correlation with clinical and surgical reports.
  
  
  METHODS
  Clinical and CT findings were retrospectively evaluated in 13 surgically proven cases of AEF. All patients underwent spiral CT examination with biphasic contrast technique, before and 30 and 80 seconds after intravenous injection of 120-150 ml of contrast medium (Ultravist 370; flow rate 2.5-3 ml/sec). Late scans (240 seconds) were also acquired on surgical anastomoses. We used 3 mm (arterial phase) and 5 mm (venous phase) slices.
  
  
  RESULTS
  At surgery, all 13 patients presented a communication between the bowel and the aortic graft. At CT examination, all 13 patients presented one or more CT signs indicating AEF (perigraft soft tissue, perigraft fluid, ectopic air or bowel wall thickening). Moreover, in 6 out of 13 patients, contrast medium extravasation from the aortic graft into the small bowel (active bleeding) was detected with CT. Detection of active bleeding was possible because CT examinations were performed without oral administration of contrast medium.
  
  
  CONCLUSIONS
  CT is easily and readily available and provides an accurate evaluation of the aorta and surrounding retroperitoneal tissues. In our study we were able to identify the CT sign of active bleeding in more than a half of the patients with acute gastrointestinal bleeding (66%). Hence, we suggest that patients undergo CT examination without oral contrast medium administration in order to better appreciate the presence of active bleeding.
authors.affiliation: Servizio e Cattedra di Radiologia, Università Vita-Salute IRCCS H San Raffaele, Milano, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Tacchini
authors.forename: Roberto
authors.initials: R
authors.lastname: Nicoletti
authors.forename: Domenica
authors.initials: D
authors.lastname: Ghio
authors.forename: Carlo Maria Andrea
authors.initials: CM
authors.lastname: Martinenghi
authors.forename: Roberto
authors.initials: R
authors.lastname: Chiesa
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Maschio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery; D001018:Aortic Diseases / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007412:Intestinal Fistula / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016157:Vascular Fistula / Q000000981:diagnostic imaging* / Q000601:surgery