title: CT analysis of caliceal anatomy in the supine and prone positions.
abstract: OBJECTIVE
  To assess the effect of patient positioning on the position of the kidneys and their consequent projection onto plain radiographs, thus ascertaining the need for special preoperative imaging.
  
  
  METHODS
  Fourteen patients were studied by obtaining fine (5-mm)-cut contrast-enhanced CT scans in the pyelogram phase in both the supine and prone position. The orientation of the kidneys relative to the midsagittal plane of the body and the orientation of the anterior and posterior calices relative to the axis of the kidney were measured from hardcopy images. Comparison was made between prone and supine positions for left and right kidneys separately, as well as overall.
  
  
  RESULTS
  The position of the patient had a small effect on the orientation of the kidneys, with the mean angle changing from 56.6 degrees when supine to 61.6 degrees when prone (p < 0.05). However, no significant change in caliceal orientation or the relative projection of the anterior and posterior calices occurred as a result.
  
  
  CONCLUSIONS
  There is no need to carry out special preoperative imaging in the operative or prone position.
authors.affiliation: Department of Urology, Royal Melbourne Hospital and The University of Melbourne, Parkville, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Sengupta
authors.forename: S
authors.initials: S
authors.lastname: Donnellan
authors.forename: J M
authors.initials: JM
authors.lastname: Vincent
authors.forename: D R
authors.initials: DR
authors.lastname: Webb
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D016684:Prone Position; D016683:Supine Position; D014057:Tomography, X-Ray Computed