title: Influence of posture change on intrarenal arterial resistive index measurement.
abstract: BACKGROUND
  We investigated the influence of posture change on intrarenal arterial resistive index measurement in 80 subjects (38 male, 42 female).
  
  
  METHODS
  Three interlobar arteries in the superior, middle, and inferior parts of the right kidney in each subject were examined by color Doppler ultrasound in two different positions (left lateral decubitus and supine). Based on the movement of the kidney caused by posture change, 23 subjects were classified as having a highly mobile kidney (group I) and the other 57 subjects were classified as not having a highly mobile kidney (group II).
  
  
  RESULTS
  Fifty-eight kidneys (72.5%), 19 in group I (82.6%) and 39 in group II (68.4%), showed higher resistive index values in the lateral decubitus position than in the supine position. The influence of posture change on resistive index measurement was significant ( p < 0.001 for all subjects, p < 0.01 for group I, p < 0.05 for group II). The ranges of resistive index differences caused by posture change were 0-0.13 for group I and 0-0.11 for group II. The difference in resistive index caused by posture change was not significant between groups.
  
  
  CONCLUSIONS
  Posture change is a potential confounding factor for intrarenal resistive index measurement.
authors.affiliation: Department of Internal Medicine, Kaohsiung Medical University Hospital, No. 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan, Republic of China.
authors.forename: Z-Y
authors.initials: ZY
authors.lastname: Lin
authors.forename: C-Y
authors.initials: CY
authors.lastname: Dai
authors.forename: W-Y
authors.initials: WY
authors.lastname: Chang
authors.forename: M-L
authors.initials: ML
authors.lastname: Yu
authors.forename: S-C
authors.initials: SC
authors.lastname: Chen
authors.forename: W-L
authors.initials: WL
authors.lastname: Chuang
authors.forename: M-Y
authors.initials: MY
authors.lastname: Hsieh
authors.forename: L-Y
authors.initials: LY
authors.lastname: Wang
authors.forename: J-F
authors.initials: JF
authors.lastname: Tsai
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture; D011446:Prospective Studies; D012077:Renal Artery / Q000000981:diagnostic imaging* / Q000502:physiology; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance