title: CT with a computer-simulated dose reduction technique for detection of pediatric nephroureterolithiasis: comparison of standard and reduced radiation doses.
abstract: OBJECTIVE
  The purpose of this study was to compare the diagnostic capabilities of standard- and reduced-dose CT in the detection of nephroureterolithiasis in children.
  
  
  METHODS
  Forty-five patients 20 years old or younger divided into two groups weighing 50 kg or less and more than 50 kg underwent unenhanced 16-MDCT in the evaluation of acute flank pain. An investigational computer-simulated tube current reduction tool was used to produce additional 80- and 40-mA examination sets (total number of image sets=135). Three independent blinded readers ranked random images for stones (confidence scale, 1-5, least to most), hydronephrosis, noise-based image quality, and presence of nonrenal lesions.
  
  
  RESULTS
  Compared with the standard tube current used for the original CT scans, there was no significant reduction (p=0.37) in detection of renal stones at the 80-mA setting (mean dose reduction, 67%; range, 43-81%); and at the 40-mA setting (mean dose reduction, 82%; range, 72-90%), the detection rate was significantly lower (p=0.05). At the 40-mA setting, there was no significant difference among the children weighing 50 kg or less (p=0.4). Detection of ureteral stones and hydronephrosis was not significantly different at 80 and 40 mA; however, disease frequency was low, and no definite conclusion can be made.
  
  
  CONCLUSIONS
  Simulated dose reduction is a useful tool for determining diagnostic thresholds for MDCT detection of renal stones in children. Use of the 80-mA setting for all children and 40 mA for children weighing 50 kg or less does not significantly affect the diagnosis of pediatric renal stones.
authors.affiliation: Department of Pediatric Radiology, Indiana University School of Medicine, Riley Hospital for Children, 702 Barnhill Dr., Rm. 1053, Indianapolis, IN 46202, USA.
authors.forename: Boaz
authors.initials: B
authors.lastname: Karmazyn
authors.forename: Donald P
authors.initials: DP
authors.lastname: Frush
authors.forename: Kimberly E
authors.initials: KE
authors.lastname: Applegate
authors.forename: Charles
authors.initials: C
authors.lastname: Maxfield
authors.forename: Mervyn D
authors.initials: MD
authors.lastname: Cohen
authors.forename: Robert P
authors.initials: RP
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D001822:Body Burden; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D008297:Male; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D053039:Ureterolithiasis / Q000000981:diagnostic imaging*; D055815:Young Adult