title: An in vivo endoluminal ultrasonographic study of peristaltic activity in the distal porcine ureter.
abstract: OBJECTIVE
  Experiments were performed to quantify the duration and frequency of ureteric peristaltic activity in the laparotomized and non-laparotomized pig in its virgin and postinstrumented states.
  
  
  METHODS
  Pigs (n = 10) in a steady state of hydration were studied under halothane anesthesia in two groups. The study was undertaken in two separate sessions at a week's interval. In group I laparotomy and vesicotomy were undertaken to obtain ELUS images. In group II, peristalsis was studied using an ELUS probe introduced through the working channel of a 22F rigid cystoscope. Peristalsis was visualized as a periodic diameter-change of ureter and recorded (for approx. 30 minutes) on videotape after an initial period of adaptation of approx. 30 minutes.
  
  
  RESULTS
  The ureter acts like a pump discharging urine into the bladder through peristaltic activity. ELUS imaging of ureteric peristalsis correlated well with "eyeballing" of the passage of peristalsis through a ureter (group I). The shortest peristaltic activity in group I was 6.0+/-2.0 seconds in the non-instrumented- and 5.1+/-1.4 seconds in the instrumented ureter. In group II it was 6.8+/-1.5 seconds in the non-instrumented- and 6.4+/-1.5 seconds in the instrumented ureter. Chronic dilatation of ureter led to decrease in peristalsis frequency. Interestingly, acute dilatation caused an increase in ureteric peristalsis frequency.
  
  
  CONCLUSIONS
  Ureteric peristalsis acts as a pump discharging urinary boluses (intraluminal fluid load) unidirectionally into the bladder. ELUS provides us an opportunity to quantify and study ureteric peristalsis.
authors.affiliation: Department of Urology, Academic Medical Center, Faculty of Medicine, Amsterdam, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Roshani
authors.forename: N F
authors.initials: NF
authors.lastname: Dabhoiwala
authors.forename: T
authors.initials: T
authors.lastname: Dijkhuis
authors.forename: K H
authors.initials: KH
authors.lastname: Kurth
authors.forename: W H
authors.initials: WH
authors.lastname: Lamers
mesh_terms: D000818:Animals; D005260:Female; D013552:Swine; D014463:Ultrasonography; D014513:Ureter / Q000000981:diagnostic imaging* / Q000502:physiology*