title: Individualized kV selection and tube current reduction in excretory phase computed tomography urography: potential for radiation dose reduction and the contribution of iterative reconstruction to image quality.
abstract: OBJECTIVE
  The objective of this study was to analyze radiation dose reduction and image quality by combining automated kV selection, tube current reduction, and iterative reconstruction.
  
  
  METHODS
  This was a retrospective analysis of the excretory phase of 55 patients with 2 computed tomography urography examinations: automated kV selection with tube current reduction ("low-dose protocol": with filtered back projection vs iterative reconstruction) and routine dose examinations. Image quality was analyzed blindly and in side-by-side analyses, in addition to quantitative measurements.
  
  
  RESULTS
  Low-dose protocol median dose change was -40% (-10.7 to +12.9 mGy); 100 kV was autoselected in 44 (80%) of 55 patients (body mass index range, 19-36 kg/m) with mean dose reduction of 42.5%. Whereas up to 19% of low-dose images with filtered back projection were inferior by blinded review (P < 0.001), low-dose iterative reconstruction images were not rated inferior (P = 1.0).
  
  
  CONCLUSIONS
  The combination of iterative reconstruction, automated kV selection, and tube current reduction results in radiation dose reduction with preserved image quality and diagnostic confidence.
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA. froemming.adam@mayo.edu
authors.forename: Adam T
authors.initials: AT
authors.lastname: Froemming
authors.forename: Akira
authors.initials: A
authors.lastname: Kawashima
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Robert P
authors.initials: RP
authors.lastname: Hartman
authors.forename: Mark A
authors.initials: MA
authors.lastname: Nathan
authors.forename: Rickey E
authors.initials: RE
authors.lastname: Carter
authors.forename: Lifeng
authors.initials: L
authors.lastname: Yu
authors.forename: Shuai
authors.initials: S
authors.lastname: Leng
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kagoshima
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
authors.forename: Joel G
authors.initials: JG
authors.lastname: Fletcher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014554:Urination; D014567:Urography / Q000379:methods*