title: Evaluation of renal resistive index, maximum velocity, and mean arterial flow velocity in a hydronephrotic partially obstructed pig model.
abstract: OBJECTIVE
  The authors investigate, in a controlled pig model, the usefulness of Doppler sonographic measurements of resistive index (RI), maximum velocity (Vmax), and mean velocity (Vmean) in diagnostic evaluation of the partially obstructed kidney.
  
  
  METHODS
  Seven female pigs underwent surgical partial unilateral renal obstruction at the ureteropelvic junction. Doppler parameters of RI, Vmax, and Vmean were measured preoperatively and postoperatively in obstructed and contralateral nonobstructed kidneys. The General Linear Model multivariate analysis of variance was used for statistical analysis of data.
  
  
  RESULTS
  There was no significant difference in the preoperative control values of RI (P = 0.71), Vmax (P = 0.27), and Vmean (P = 0.12). There was a statistically significant decrease in the Vmax and Vmean after postoperative day 5 in the obstructed kidney compared with the contralateral nonobstructed kidney (P = 0.01 and 0.03, respectively). There was no statistically significant difference in RI during the study.
  
  
  CONCLUSIONS
  In this study, RI was not a reliable indicator of partial renal obstruction. Measurements of maximal and mean blood flow velocities reached discriminatory significance only after the fifth postobstructive day, proving insensitive in the immediate postobstructive period. Vmax and Vmean demonstrated a decrease in the partially obstructed renal collecting system after 5 days of obstruction and may serve as useful parameters in the evaluation of obstruction after the immediate acute period, when compared with a nonobstructed contralateral system.
authors.affiliation: Department of Radiology & Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232-2675, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Cole
authors.forename: J W
authors.initials: JW
authors.lastname: Brock
authors.forename: J C
authors.initials: JC
authors.lastname: Pope
authors.forename: F F
authors.initials: FF
authors.lastname: Schrum
authors.forename: D F
authors.initials: DF
authors.lastname: Milam
authors.forename: J E
authors.initials: JE
authors.lastname: Flickinger
authors.forename: P R
authors.initials: PR
authors.lastname: Showalter
authors.forename: J A
authors.initials: JA
authors.lastname: Worrell
authors.forename: M
authors.initials: M
authors.lastname: Hernanz-Schulman
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity; D005260:Female; D006869:Hydronephrosis / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012079:Renal Circulation; D013552:Swine; D018608:Ultrasonography, Doppler; D014517:Ureteral Obstruction / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014655:Vascular Resistance