title: Low-dose multidetector-row CT-angiography of abdominal aortic aneurysm after endovascular repair.
abstract: OBJECTIVE
  To investigate the possibility of reducing radiation dose exposure while maintaining image quality using multidetector computed tomography angiography (MDCTA) with high-concentration contrast media in patients undergoing follow-up after endovascular aortic repair (EVAR) to treat abdominal aortic aneurysm.
  
  
  METHODS
  In this prospective, single center, intra-individual study, patients underwent two consecutive MDCTA scans 6 months apart, one with a standard acquisition protocol (130 mAs/120 kV) and 120 mL of iomeprol 300, and one using a low dose protocol (100 mAs/80 kV) and 90 mL of iomeprol 400. Images acquired during the arterial phase of contrast enhancement were evaluated both qualitatively and quantitatively for image noise and intraluminal contrast enhancement.
  
  
  RESULTS
  Thirty adult patients were prospectively enrolled. Statistically significantly higher attenuation values were measured in the low-dose acquisition protocol compared to the standard protocol, from the suprarenal abdominal aorta to the common femoral artery (p<0.0001; all vascular segments). Qualitatively, image quality was judged significantly (p=0.0002) better with the standard protocol than with the low-dose protocol. However, no significant differences were found between the two protocols in terms of contrast-to-noise ratio (CNR) (13.63±6.97 vs. 11.48±8.13; p=0.1058). An overall dose reduction of up to 74% was observed for the low-dose protocol compared with the standard protocol.
  
  
  CONCLUSIONS
  In repeat follow-up examinations of patients undergoing EVAR for abdominal aortic aneurysm, a low-dose radiation exposure acquisition protocol provides substantially reduced radiation exposure while maintaining a constant CNR and good image quality.
authors.affiliation: Department of Bioimaging and Radiological Sciences, Institute of Radiology, "A. Gemelli" Hospital - Catholic University, L.go A Gemelli 8, 00168 Rome, Italy. iezzir@virgilio.it
authors.forename: R
authors.initials: R
authors.lastname: Iezzi
authors.forename: A R
authors.initials: AR
authors.lastname: Cotroneo
authors.forename: A
authors.initials: A
authors.lastname: Giammarino
authors.forename: F
authors.initials: F
authors.lastname: Spigonardo
authors.forename: M L
authors.initials: ML
authors.lastname: Storto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging* / Q000601:surgery*; D003287:Contrast Media; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol