title: Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT.
abstract: OBJECTIVE
  To assess the diagnostic performance of dual-energy dual-source computed tomography (CT) in the detection of endoleaks after endovascular abdominal aortic aneurysm (AAA) repair.
  
  
  METHODS
  This study was local ethics board approved, and written informed consent was obtained from all patients. One hundred eighteen patients (21 women, 97 men; mean age, 74 years +/- 8 [standard deviation]) underwent follow-up dual-energy dual-source CT during the nonenhanced, arterial, and delayed phases after AAA repair. Delayed phase CT images were acquired in the dual-energy mode for reconstruction of virtual nonenhanced images. Two blinded and independent readers evaluated the data for the presence or absence of endoleaks during three reading sessions: Standard nonenhanced, arterial phase, and delayed phase images were read during session A; virtual nonenhanced, arterial phase, and delayed phase images, during session B; and virtual nonenhanced and delayed phase images, during session C. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, with the session A image data set as the reference standard. Radiation dose parameters were estimated.
  
  
  RESULTS
  Reading session A revealed that 52 (44%) of 118 patients had endoleaks. Overall sensitivity, specificity, NPV, and PPV for CT endoleak detection during sessions B and C were identical: 100%, 97%, 100%, and 96%, respectively. The accuracy of the session B and session C readings was not significantly different from that of the session A reading (P = .50). The effective radiation dose in the image acquisition protocol involving one dual-energy scan was significantly (P < .001) lower than the effective doses in the protocols involving standard triple-phase scanning (mean difference, 61%) and standard nonenhanced and delayed phase scanning (mean difference, 41%).
  
  
  CONCLUSIONS
  Compared with standard protocols, one dual-energy dual-source CT scan performed during the delayed phase with reconstruction of virtual nonenhanced images enables detection of endoleaks after endovascular AAA repair with high accuracy and a considerably lower radiation dose.
authors.affiliation: Institute of Diagnostic Radiology, University Hospital Zurich, Zurich, Switzerland.
authors.forename: Paul
authors.initials: P
authors.lastname: Stolzmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Frauenfelder
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfammatter
authors.forename: Nicole
authors.initials: N
authors.lastname: Peter
authors.forename: Hans
authors.initials: H
authors.lastname: Scheffel
authors.forename: Mario
authors.initials: M
authors.lastname: Lachat
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schmidt
authors.forename: Borut
authors.initials: B
authors.lastname: Marincek
authors.forename: Hatem
authors.initials: H
authors.lastname: Alkadhi
authors.forename: Thomas
authors.initials: T
authors.lastname: Schertler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D011237:Predictive Value of Tests; D012372:ROC Curve; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013529:Surgical Wound Dehiscence / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol