title: Ultra-low-dose computed tomographic angiography with model-based iterative reconstruction compared with standard-dose imaging after endovascular aneurysm repair: a prospective pilot study.
abstract: OBJECTIVE
  An ultra-low-dose radiation protocol reconstructed with model-based iterative reconstruction was compared with our standard-dose protocol.
  
  
  METHODS
  This prospective study evaluated 20 men undergoing surveillance-enhanced computed tomography after endovascular aneurysm repair. All patients underwent standard-dose and ultra-low-dose venous phase imaging; images were compared after reconstruction with filtered back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction. Objective measures of aortic contrast attenuation and image noise were averaged. Images were subjectively assessed (1 = worst, 5 = best) for diagnostic confidence, image noise, and vessel sharpness. Aneurysm sac diameter and endoleak detection were compared.
  
  
  RESULTS
  Quantitative image noise was 26% less with ultra-low-dose model-based iterative reconstruction than with standard-dose adaptive statistical iterative reconstruction and 58% less than with ultra-low-dose adaptive statistical iterative reconstruction. Average subjective noise scores were not different between ultra-low-dose model-based iterative reconstruction and standard-dose adaptive statistical iterative reconstruction (3.8 vs. 4.0, P = .25). Subjective scores for diagnostic confidence were better with standard-dose adaptive statistical iterative reconstruction than with ultra-low-dose model-based iterative reconstruction (4.4 vs. 4.0, P = .002). Vessel sharpness was decreased with ultra-low-dose model-based iterative reconstruction compared with standard-dose adaptive statistical iterative reconstruction (3.3 vs. 4.1, P < .0001). Ultra-low-dose model-based iterative reconstruction and standard-dose adaptive statistical iterative reconstruction aneurysm sac diameters were not significantly different (4.9 vs. 4.9 cm); concordance for the presence of endoleak was 100% (P < .001).
  
  
  CONCLUSIONS
  Compared with a standard-dose technique, an ultra-low-dose model-based iterative reconstruction protocol provides comparable image quality and diagnostic assessment at a 73% lower radiation dose.
authors.affiliation: Department of Radiology, Mayo Clinic Hospital, 5777 E Mayo Blvd, 85054, Phoenix, AZ, USA, naidu.sailen@mayo.edu.
authors.forename: Sailen G
authors.initials: SG
authors.lastname: Naidu
authors.forename: J Scott
authors.initials: JS
authors.lastname: Kriegshauser
authors.forename: Robert G
authors.initials: RG
authors.lastname: Paden
authors.forename: Miao
authors.initials: M
authors.lastname: He
authors.forename: Qing
authors.initials: Q
authors.lastname: Wu
authors.forename: Amy K
authors.initials: AK
authors.lastname: Hara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D003287:Contrast Media; D057510:Endovascular Procedures / Q000379:methods; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D010865:Pilot Projects; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D007472:Iohexol