title: Quality-controlled dose reduction of full-leg radiography in patients with knee malalignment.
abstract: OBJECTIVE
  Digital plain radiographs of the full leg are frequently performed examinations of children and young adults. Thus, the objective of this work was to reduce the radiation exposure dependent on specific indications, and to determine objective quality-control criteria to ensure accurate assessment.
  
  
  METHODS
  Institutional review board approval and informed consent of all participants were obtained. In this prospective, randomized controlled, blinded, two-armed single-center study, 288 evaluable patients underwent plain radiography of the full leg with standard and reduced doses. The evaluation of the plain radiographs was conducted using the following criteria: mechanical axis, leg length, and maturation of the epiphyseal plate. Two blinded radiologists evaluated these criteria using a score ranging from 1 (definitely assessable) to 4 (not assessable). If a single criterion had been evaluated with a score of 3 or more points or all criteria with 2 points, the radiograph was scored as "not assessable". The study was designed as a non-inferiority trial.
  
  
  RESULTS
  Eleven (3.8%) examined X-rays were scored as not assessable. The rate of non-assessable radiographs with 33% reduced dose was significantly not inferior to the rate of non-assessable radiographs with standard dose. The evaluation of the quality criteria was dose independent.
  
  
  CONCLUSIONS
  Full-leg plain radiography in patients with knee malalignment can be performed at 33% reduced dose without loss of relevant diagnostic information.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 110, 69120, Heidelberg, Germany, jost.kloth@med.uni-heidelberg.de.
authors.forename: Jost Karsten
authors.initials: JK
authors.lastname: Kloth
authors.forename: Regina
authors.initials: R
authors.lastname: Neumann
authors.forename: Eva
authors.initials: E
authors.lastname: von Stillfried
authors.forename: Wolfram
authors.initials: W
authors.lastname: Stiller
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Volker
authors.initials: V
authors.lastname: Ewerbeck
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Weber
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017760:Bone Malalignment / Q000000981:diagnostic imaging*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D031221:Knee Dislocation / Q000000981:diagnostic imaging*; D007866:Leg / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011786:Quality Control; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods* / Q000592:standards; D011859:Radiography / Q000379:methods / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D055815:Young Adult