title: Short- and long-term repeatability of intrarenal resistive index in the pig.
abstract: OBJECTIVE
  To evaluate the short- and long-term repeatability (intraobserver variation) of the renal resistive index (RI) in a pig model.
  
  
  METHODS
  Under standardized ambient conditions, short- and long-term repeatabilities were assessed by measuring the RI three consecutive times at 30-minute intervals in 14 pigs and twice 4 weeks apart in 6 pigs, respectively. Repeatability was judged according to predefined criteria, which included calculation of coefficients of variation (CVs) and repeatability coefficients combined with visual assessment and estimation of bias.
  
  
  RESULTS
  Short-term repeatability was acceptable, having an average CV of 4.9% +/- 2.9% and of 6.1% +/- 4.7% in two comparisons, findings that were reiterated in the visual assessment. Long-term results were, however, less consistent, having an average CV of 8.1% +/- 6.1% and prominent scatter on the visual assessment graphs.
  
  
  CONCLUSIONS
  In this study, RI measurements showed an acceptable short-term repeatability, whereas long-term results were less consistent. The components of error contributing to the modest long-term repeatability need to be investigated in studies of larger populations.
authors: Institute of Experimental Clinical Research, Aarhus University Hospital-Skejby, Aarhus, Denmark. jazcat@dadlnet.dk
authors: Y F
authors: YF
authors: Rawashdeh
authors: A
authors: A
authors: Hørlyck
authors: J
authors: J
authors: Mortensen
authors: J
authors: J
authors: Frokiaer
mesh_terms: D000818:Animals; D001794:Blood Pressure; D005260:Female; D015588:Observer Variation; D012079:Renal Circulation; D015203:Reproducibility of Results; D013552:Swine; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance