title: Magnetic resonance imaging in the evaluation of pelvi-ureteric junction obstruction: an all-in-one approach.
abstract: OBJECTIVE
  To study the ability of comprehensive magnetic resonance imaging (MRI) to replace multiple imaging methods in the evaluation of patients with pelvi-ureteric junction obstruction (PUJO).
  
  
  METHODS
  Between May 2003 and November 2005, 46 consecutive patients (22 male and 24 females; mean age 31.6 years) with symptomatic primary PUJO were included. All had comprehensive MRI, including MR urography (MRU), dynamic MRI and MR angiography (MRA). Morphological results of MRU were compared with that of renal ultrasonography or intravenous urography, while the anatomical results of MRA were compared with the operative findings. A correlation between MR clearance and radioisotope clearance was done using linear regression analysis.
  
  
  RESULTS
  MRU showed the morphology of the collecting system in all patients, and the ureter below the PUJ in 31 of 46 (67%), but renal stones were missed in three of 10 patients. MRA showed crossing vessels in 22 patients (48%). There was a strong correlation between MR clearance and radioisotope clearance (r = 0.823, P < 0.001). From the MRI results, 35 patients (19 with crossing vessels and 16 with marked hydronephrosis) had pyeloplasty and 11 had an endopyelotomy. Findings during pyeloplasty showed one false-negative and one false-positive result of the preoperative MRI. Therefore, the sensitivity, specificity and accuracy of MRA were 95%, 94% and 94%, respectively. The outcome was successful in 44 (96%) patients. One failure after pyeloplasty was managed with endopyelotomy and the other was treated with pyeloplasty after endopyelotomy.
  
  
  CONCLUSIONS
  Comprehensive MRI is a valuable and accurate single-imaging method for evaluating patients with PUJO.
authors.affiliation: Department of Urology, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt. ar_el_nahas@yahoo.com
authors.forename: Ahmed R
authors.initials: AR
authors.lastname: El-Nahas
authors.forename: Mohamed E
authors.initials: ME
authors.lastname: Abou El-Ghar
authors.forename: Huda F
authors.initials: HF
authors.lastname: Refae
authors.forename: Hossam M
authors.initials: HM
authors.lastname: Gad
authors.forename: Tarek A
authors.initials: TA
authors.lastname: El-Diasty
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000175:diagnosis*; D007682:Kidney Pelvis / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000592:standards*; D008297:Male; D011446:Prospective Studies; D014517:Ureteral Obstruction / Q000175:diagnosis*