title: Multidetector CT in abdominal aortic aneurysm treated with endovascular repair: are unenhanced and delayed phase enhanced images effective for endoleak detection?
abstract: OBJECTIVE
  To retrospectively determine the sensitivity and specificity of unenhanced, delayed enhanced phase (DEP), and arterial enhanced phase (AEP) multi-detector row computed tomography (CT) for depicting endoleaks during follow-up of endovascular aneurysm repair.
  
  
  METHODS
  Fifty patients (two women, 48 men; mean age, 72 years) underwent follow-up multi-detector row CT 1, 6, and 12 months after endovascular aneurysm repair. Unenhanced CT was performed with 2.5-mm collimation; 1-mm collimation was used with AEP and DEP examinations. Two independent readers assessed the presence of endoleak in three reading sessions: AEP (session A), unenhanced and AEP (session B), and AEP and DEP (session C). At 6- and 12-month follow-up, a fourth set was included: 1-month unenhanced and AEP (session D). Sensitivity, specificity, and positive predictive value of each session were calculated. Triple-phase multi-detector row CT was the reference standard.
  
  
  RESULTS
  At 1 month, sensitivity, specificity, and positive predictive value, respectively, were 79%, 75%, and 55% for session A; 93%, 97%, and 93% for session B; and 93%, 78%, and 62% for session C. At 6 months, sensitivity, specificity, and positive predictive value, respectively, were 92%, 68%, and 48% for session A; 92%, 100%, and 100% for session B; and 100%, 84%, and 67% for session C. At 12 months, sensitivity, specificity, and positive predictive value, respectively, were 80%, 80%, and 50% for session A; 90%, 98%, and 90% for session B; and 100%, 80%, and 56% for session C. Sensitivity did not significantly differ (P > .05) among reading sessions A, B, and C, whereas specificity and positive predictive values in session B were significantly higher (P < .001). For 6- and 12-month follow-up, no significant differences (P > .05) were found between sessions D and B.
  
  
  CONCLUSIONS
  The combination of AEP and unenhanced imaging performed at 1-month follow-up offers improved specificity and positive predictive values compared with AEP alone. DEP imaging does not significantly increase sensitivity for detection of endoleaks, but it does depict low-flow endoleaks not seen at AEP.
authors.affiliation: Department of Clinical Science and Bioimaging, Section of Radiology, G. D'Annunzio University, SS Annunziata Hospital, Via dei Vestini, 66013 Chieti, Italy. r.iezzi@rad.unich.it
authors.forename: Roberto
authors.initials: R
authors.lastname: Iezzi
authors.forename: Antonio Raffaele
authors.initials: AR
authors.lastname: Cotroneo
authors.forename: Antonella
authors.initials: A
authors.lastname: Filippone
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Fabio
authors.forename: Fabio
authors.initials: F
authors.lastname: Quinto
authors.forename: Cesare
authors.initials: C
authors.lastname: Colosimo
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bonomo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000628:therapy*; D019917:Blood Vessel Prosthesis Implantation; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol