title: Abdominal Computed Tomography Angiography at 80kV: feasibility study.
abstract: OBJECTIVE
  preliminary evaluation of different dose reduction algorithms in abdominal Computed Tomography Angiography (CTA) with standard scan protocols at 120kV vs. 80kV.
  
  
  METHODS
  prospective, randomized, crossover study. 60 consecutive patients who underwent CTA of the abdomen (Sensation 64, Siemens; Iomeprol 400 mgl/ml Bracco) for suspected or diagnosed Abdominal Aortic Aneurysm (AAA) were enrolled in the study. A standard 120kV/200mAs scan protocol was acquired in all patients (reference tube current modulated with Automatic Exposure Control). In each patient a second scan with 80kV/300mAs (Group 1; n. 20), 80kV/400mAs (Group 2; n. 20), 80kV/500mAs (Group 3; n. 20) was acquired. We used the same scan/reconstruction parameters with the same amount and kind of contrast medium. The radiation dose, the aortic attenuation values, the noise and the signal/noise ratio (S/N) were evaluated.
  
  
  RESULTS
  the mean dose was 9.7±2.7mSv for 120kV (all patients), 3.6±0.8mSv in Group1 (80kV), 5.0±0.6mSv in Group 2 (80kV) and 5.9±1.2mSv in Group 3 (80kV), respectively. The aortic attenuation was 350±59HU (120kV) vs. 534±100HU (80kV), 12±3.5 (120kV) vs. 8.8±3.6 (80kV) for the whole population. Aortic attenuation and S/N were: 328±40HU (120kV) vs. 494±61HU (80kV), 11±2 (120kV) vs. 7±2 (80kV) in Group1; 353±77HU (120kV) vs. 551±117HU (80kV), 11±2.8HU (120kV) vs. 8.4±2.6 (80kV) in Group 2; 389±55HU (120kV) vs. 598±117HU (80kV), 15±5 (120kV) vs. 12±5 (80kV) in Group 3, respectively (p&lt;0.05).
  
  
  CONCLUSIONS
  in abdominal CTA, the 80kV/400mAs scan protocol allows a radiation dose reduction of 50% without a significant reduction of S/N ratio.
authors.affiliation: . filippocademartiri@gmail.com.
authors.forename: Erica
authors.initials: E
authors.lastname: Maffei
authors.forename: Teresa
authors.initials: T
authors.lastname: Arcadi
authors.forename: Ludovico
authors.initials: L
authors.lastname: La Grutta
authors.forename: Massimo
authors.initials: M
authors.lastname: Midiri
authors.forename: Carlo
authors.initials: C
authors.lastname: Tedeschi
authors.forename: Andrea
authors.initials: A
authors.lastname: Guaricci
authors.forename: Chiara
authors.initials: C
authors.lastname: Martini
authors.forename: Cesare
authors.initials: C
authors.lastname: Mantini
authors.forename: Filippo
authors.initials: F
authors.lastname: Cademartiri
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000792:Angiography; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D018592:Cross-Over Studies; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed