title: Hemodynamic investigation of the left renal vein in pediatric varicocele: Doppler US, venography, and pressure measurements.
abstract: OBJECTIVE
  To evaluate prospectively the hemodynamic state of the left renal vein with Doppler ultrasonography (US) and venography in pediatric patients with varicocele to assess the "nutcracker phenomenon."
  
  
  METHODS
  The institutional review board considered this study ethically sound, and parental informed consent was obtained for all subjects. Doppler US of the left renal vein was performed in 27 consecutive boys with varicocele (age range, 7-15 years; mean, 11.9 years) and in 20 boys without varicocele as control subjects (age range, 7-17 years; mean, 11.4 years). Doppler US was used to evaluate left renal vein diameters and peak velocities in the proximal left renal vein near the renal hilum and in the left renal vein between the aorta and superior mesenteric artery (aortomesenteric portion). The diameter ratios and peak velocity ratios between two sites were obtained. For statistical comparison of results, the t test was used. Left renal venography and renocaval pressure measurement were performed in 13 patients with varicocele. The Fisher exact test was used to evaluate the associations between the nutcracker phenomenon (renocaval pressure gradient >/=3 mm Hg) and the development of collateral veins.
  
  
  RESULTS
  The diameters of the proximal left renal vein and the peak velocities in the aortomesenteric portion of the left renal vein were significantly different between the varicocele group and the control group (P < .001). The diameter ratios (5.7 +/- 1.8 [standard deviation]) and peak velocity ratios (5.2 +/- 2.6) in patients with varicocele were significantly higher than those in control subjects (3.5 +/- 1.0 and 3.1 +/- 0.8, respectively) (P < .005). According to findings at left renal venography (n = 13), 10 patients (77%) met the criteria for the nutcracker phenomenon. The nutcracker phenomenon was significantly associated with the development of collateral veins (P = .035).
  
  
  CONCLUSIONS
  Doppler US and venography of the left renal vein can show hemodynamic changes of the left renal vein and depict the presence of the nutcracker phenomenon in pediatric varicocele.
authors.affiliation: Department of Radiology, Seoul National University College of Medicine and the Institute of Radiation Medicine, SNUMRC, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea.
authors.forename: Woo Sun
authors.initials: WS
authors.lastname: Kim
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Cheon
authors.forename: In-One
authors.initials: IO
authors.lastname: Kim
authors.forename: Seung Hyup
authors.initials: SH
authors.lastname: Kim
authors.forename: Kyung Mo
authors.initials: KM
authors.lastname: Yeon
authors.forename: Kwang Myung
authors.initials: KM
authors.lastname: Kim
authors.forename: Hwang
authors.initials: H
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D008297:Male; D008365:Manometry; D010690:Phlebography; D011446:Prospective Studies; D012082:Renal Veins / Q000000981:diagnostic imaging / Q000503:physiopathology*; D018608:Ultrasonography, Doppler; D014646:Varicocele / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014690:Venous Pressure