MR urography in pediatric uropathies with dilated urinary tracts.

PURPOSE To determine the diagnostic value of magnetic resonance (MR) urography in children with urinary tract dilatation. MATERIALS AND METHODS Twenty-five children between the ages of 4 months and 13 years (19 males and 6 females, mean age 6.5 years) were evaluated with T2 weighted and contrast-enhanced T1 weighted MR sequences. Results were compared with findings obtained with ultrasonography (n=25), intravenous urography (n=18), Tc99m- DTPA scintigraphy (n=16), and/or micturating cystouretrography (n=13). RESULTS MR urography provided a superior imaging of urinary system dilatation, the site and the etiology of obstruction, and both regular and complicated kidney duplication than did conventional imaging methods. MR urography that used T2 weighted sequences was able to demonstrate 29 of 32 (90.6%) abnormal renal collecting systems. Fourteen of 21 (66.7%) normal systems were revealed by heavily T2 weighted images. Forty-six of 51 (90.2%) renal collecting systems could be shown by T1 weighted sequences. With this sequence, however, five collecting systems (9.8%) could not be shown secondary to poor renal function and/or dilution of contrast agent within the dilated urinary tract. CONCLUSION In children, MR urography may replace conventional uroradiological methods.