ABSTRACT
We evaluated the role of magnetic resonance urography [MRU] in the diagnosis of the cause and level of. upper urinary tract obstruction as non-invasive technique when the conventional IVU is non conclusive or contraindicated. Our study included 62 patients of them 33 patients with unilateral obstruction, 20 patients with bilateral obstruction and 9 patients with obstructed solitary kidney. Non enhanced T2-weighted MRU was done to diagnose the etiology of uretral obstruction compared to the gold standard of diagnosis of obstruction which was retrograde or antegrade urography, uretroscopy or open surgery. We found that in calcular obstruction the sensitivity specificity and overall accuracy were respectively [70.6%, 97.1% and 83,5%] while for non-caleular obstruction were [95.8%, 97.1% and 96.3%] there was a statistically significant difference between the sensitivity of MRU in diagnosing the cause of obstruction in calcular and non-calcular etiology in favor of non-caleular obstruction [p value = 0.01]. The overall sensitivity of MRU in diagnosis of the cause of obstruction was 85.4%, specificity of 97.1% overall accuracy of 89.2%. In conclusion MRU is a sensitive test for diagnosis of the level and cause of upper tract obstruction when IVU is contraindicated or non-conclusive in non-caleular obstruction, but the sensitivity is lower in detection of calcular obstruction. The addition of KUB and abdominal ultrasonography increase the sensitivity of MRU in diagnosis of calcular upper urinary tract obstruction