MR urography versus retrograde pyelography/ureteroscopy for the exclusion of upper urinary tract malignancy

Aim: To evaluate the diagnostic performance of magnetic resonance urography (MRU) versus retrograde pyelography and/or ureteroscopy (RPU) in the detection of upper urinary tract neoplasms. Materials and methods: This retrospective study included 35 patients with suspected upper urinary tract malignancy who underwent MRU and RPU within 6-months in our institution during the study period (February 2002 to January 2007). MRU and RPU reports were reviewed and results recorded. For each patient, the urinary tract was sub-divided into four regions for analysis: left kidney/renal pelvis, left ureter, right kidney/renal pelvis, and right ureter. MRU and RPU results for each patient were compared to a reference standard and the diagnostic performance of both techniques was compared. Results: A total of 113 regions were analysed on MRU and 90 regions on RPU. Nineteen neoplasms were identified. Sensitivity, specificity, positive predictive value, and negative predictive value for the detection of urinary tract neoplasms were 63, 91, 60, and 92% for MRU, respectively, and 53, 97, 83, and 88% for RPU, respectively. These differences were not statistically significant (p > 0.05). Conclusion: The high negative predictive value of MRU in the present series supports its use as a non-invasive screening examination for excluding the presence of upper urinary tract malignancy.