title: Abdominal aorta: evaluation with dual-source dual-energy multidetector CT after endovascular repair of aneurysms--initial observations.
abstract: OBJECTIVE
  To evaluate the possible radiation dose reduction facilitated by using dual-energy (DE) multidetector computed tomography (CT) after endovascular repair of abdominal aortic aneurysms (AAAs).
  
  
  METHODS
  This prospective study was HIPAA compliant and institutional review board approved. Twenty-two patients who previously had undergone endovascular repair of AAAs underwent 24 DE multidetector CT examinations, which were performed with a 64-detector scanner. Initial nonenhanced CT was followed by arterial phase and venous phase acquisitions. Virtual nonenhanced, pure 80-kVp, and weighted-average peak voltage CT data sets were generated from the venous acquisition. Two independent readers interpreted the virtual nonenhanced and DE weighted-average CT data for the presence or absence of endoleaks. These interpretations were compared with the clinical interpretations of the data performed by a different radiologist by using true nonenhanced, arterial phase, and venous phase data. Region-of-interest measurements of the abdominal aorta and of the region of the endoleaks were obtained. Effective radiation dose was calculated.
  
  
  RESULTS
  Both independent readers' interpretations of the virtual nonenhanced and weighted-average venous CT data revealed six type II endoleaks. There were no false-positive or false-negative findings. Aortic attenuation during the arterial, 80-kVp venous, and weighted-average data acquisitions were 288, 213, and 150 HU, respectively. The attenuation of the endoleaks was higher during the 80-kVp acquisition (P < .03) than during the arterial phase and weighted-average venous phase acquisitions. The mean effective dose for DE venous phase CT was 11.1 mSv compared with 27.8 mSv for standard triple-phase CT with a single-source configuration.
  
  
  CONCLUSIONS
  Preliminary observations suggest that obtaining DE multidetector CT data by using a single 60-second contrast material-enhanced acquisition may be all that is required for surveillance after endovascular repair of AAA.
authors.affiliation: Department of Radiology, New York University Medical Center, Tisch Hospital, New York, NY 10016, USA.
authors.forename: Hersh
authors.initials: H
authors.lastname: Chandarana
authors.forename: Myrna C B
authors.initials: MC
authors.lastname: Godoy
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vlahos
authors.forename: Anno
authors.initials: A
authors.lastname: Graser
authors.forename: James
authors.initials: J
authors.lastname: Babb
authors.forename: Christianne
authors.initials: C
authors.lastname: Leidecker
authors.forename: Michael
authors.initials: M
authors.lastname: Macari
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging* / Q000601:surgery; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide