Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: comparison with operative findings.

摘要

BACKGROUND: Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. OBJECTIVE: To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. MATERIALS AND METHODS: We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. RESULTS: CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (chi2=14.0; P<0.001).In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CONCLUSION: CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction.