title: The role of static magnetic resonance urography in the evaluation of obstructive uropathy.
abstract: OBJECTIVE
  To assess the diagnostic accuracy of static magnetic resonance urography (MRU) in hydronephrosis and to compare parameters of hydronephrosis in MRU with intravenous urography (IVU).
  
  
  METHODS
  Sixty-nine patients were included in this study of which 55 patients with a total of 63 hydronephrotic units underwent both IVU and MRU. MRU was performed on a 1.5 T scanner using heavily T2-weighted sequences. The level, grade, and cause of obstruction on each modality were interpreted by 2 radiologists. These were compared with the final diagnosis based on other appropriate modalities including imaging, intraoperative and histopathologic diagnosis.
  
  
  RESULTS
  The sensitivity and specificity MRU in detecting hydronephrosis were 95% and 100%, respectively. In determining the level of obstruction, the strength of agreement between IVU and MRU using kappa statistics was κ = 0.66, which corresponds to a good level of agreement. The Spearman correlation coefficient for the grade of hydronephrosis on MRU and IVU was 0.92 (95% confidence interval 0.86-0.95), with a P value of < .0001. The correct diagnosis was made in 89.2% of the cases by IVU and in 93.8% of the cases by MRU.
  
  
  CONCLUSIONS
  Along with a high sensitivity and specificity in detecting the presence, level, and grade of hydronephrosis, MRU without contrast also shows a good agreement with IVU. Static MRU can reliably replace IVU when the latter is contraindicated or technically difficult.
authors.affiliation: Department of Radiodiagnosis, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India. prakashmuthusami@gmail.com
authors.forename: Prakash
authors.initials: P
authors.lastname: Muthusami
authors.forename: Venkatesan
authors.initials: V
authors.lastname: Bhuvaneswari
authors.forename: Sundararajan
authors.initials: S
authors.lastname: Elangovan
authors.forename: Lalgudi N
authors.initials: LN
authors.lastname: Dorairajan
authors.forename: Ananthakrishnan
authors.initials: A
authors.lastname: Ramesh
mesh_terms: D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D014517:Ureteral Obstruction / Q000175:diagnosis*; D014567:Urography / Q000379:methods