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


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.


CONCLUSIONS
CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction.
Calder
Alistair D
AD
Department of Radiology, Great Ormond Street Hospital for Children NHS Trust, London, WC1N 3JH, UK.
Hiorns
Melanie P
MP
Abhyankar
Aruna
A
Mushtaq
Imran
I
Olsen
Oystein E
OE
D000293:Adolescent; D002648:Child; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D005355:Fibrosis; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007275:Injections, Intravenous; D007682:Kidney Pelvis / Q000098:blood supply*; D010535:Laparoscopy; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D015609:Organotechnetium Compounds; D011866:Radioisotope Renography; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D014513:Ureter / Q000098:blood supply; D014517:Ureteral Obstruction / Q000175:diagnosis* / Q000601:surgery
D003287:Contrast Media; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D019786:Gadolinium DTPA