title: Detection of Urothelial Carcinoma: Comparison of Reduced-Dose Iterative Reconstruction with Standard-Dose Filtered Back Projection.
abstract: OBJECTIVE
  To prospectively assess radiation dose, image quality, and diagnostic performance of computed tomography (CT) urography for detection of urothelial carcinomas by performing reduced-dose scanning with iterative reconstruction (IR) compared with standard-dose scanning with filtered back projection (FBP).
  
  
  METHODS
  The institutional review board approved the study with written informed patient consent. In total, 2163 patients at high risk for urothelial carcinomas randomly underwent standard-dose scanning with FBP (protocol A, 120 kVp for >80 kg body weight; protocol B, 100 kVp for 50-80 kg body weight) or reduced-dose scanning with IR (protocol C, 100 kVp for >80 kg body weight; protocol D, 80 kVp for 50-80 kg body weight). Objective image quality (signal-to-noise ratio and contrast-to-noise ratio) between the two groups with same weight range was measured for various regions of interest. Subjective image quality (visual image noise, artifact, ureter depiction, and overall image quality) and diagnostic accuracy (per lesion and per patient) were assessed with three- and five-point scores, respectively.
  
  
  RESULTS
  Size-specific dose estimate (protocol A vs protocol C, 24.2 mGy vs 19.2 mGy, respectively; protocol B vs protocol D,13.9 mGy vs 8.8 mGy, respectively) was significantly lower in reduced-dose scanning (P < .001 for both). There were significantly higher signal-to-noise and contrast-to-noise ratios in reduced-dose scanning, except for the abdominal aorta (P < .05 for all). There was no significant difference in subjective image quality, except for artifacts in protocols B and D (range, 4-5 vs 3-4; P < .05). Per-lesion diagnostic accuracy was 90.8% (89 of 98, protocol A), 91.3% (105 of 115, protocol B), 92.9% (79 of 85, protocol C), and 88.8% (111 of 125, protocol D).
  
  
  CONCLUSIONS
  Reduced-dose scanning with IR showed dose reduction and no significant difference of image quality in detection of urothelial carcinomas, except for some artifacts in 80-kVp scanning.
authors.affiliation: From the Department of Radiology, Keimyung University, Dongsan Hospital, 56 Dalsungro, Jung-gu, Daegu 700-712, Korea (Y.E.B., S.H.K., M.J.K., C.S.K., Y.H.K.); and Department of Radiology, Kyungbook National University Hospital, Daegu, Korea (S.H.C.).
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Bahn
authors.affiliation: From the Department of Radiology, Keimyung University, Dongsan Hospital, 56 Dalsungro, Jung-gu, Daegu 700-712, Korea (Y.E.B., S.H.K., M.J.K., C.S.K., Y.H.K.); and Department of Radiology, Kyungbook National University Hospital, Daegu, Korea (S.H.C.).
authors.forename: See Hyung
authors.initials: SH
authors.lastname: Kim
authors.affiliation: From the Department of Radiology, Keimyung University, Dongsan Hospital, 56 Dalsungro, Jung-gu, Daegu 700-712, Korea (Y.E.B., S.H.K., M.J.K., C.S.K., Y.H.K.); and Department of Radiology, Kyungbook National University Hospital, Daegu, Korea (S.H.C.).
authors.forename: Mi Jeong
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: From the Department of Radiology, Keimyung University, Dongsan Hospital, 56 Dalsungro, Jung-gu, Daegu 700-712, Korea (Y.E.B., S.H.K., M.J.K., C.S.K., Y.H.K.); and Department of Radiology, Kyungbook National University Hospital, Daegu, Korea (S.H.C.).
authors.forename: Chan Sun
authors.initials: CS
authors.lastname: Kim
authors.affiliation: From the Department of Radiology, Keimyung University, Dongsan Hospital, 56 Dalsungro, Jung-gu, Daegu 700-712, Korea (Y.E.B., S.H.K., M.J.K., C.S.K., Y.H.K.); and Department of Radiology, Kyungbook National University Hospital, Daegu, Korea (S.H.C.).
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Kim
authors.affiliation: From the Department of Radiology, Keimyung University, Dongsan Hospital, 56 Dalsungro, Jung-gu, Daegu 700-712, Korea (Y.E.B., S.H.K., M.J.K., C.S.K., Y.H.K.); and Department of Radiology, Kyungbook National University Hospital, Daegu, Korea (S.H.C.).
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Cho
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D002295:Carcinoma, Transitional Cell / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging*; D014567:Urography / Q000379:methods*