Magnetic resonance urography in patients with neurogenic bladder dysfunction and spinal dysraphism

To investigate the reliability of magnetic resonance urography (MRU) using heavily T2-weighted very fast spin-echo sequences in imaging the upper urinary tract in patients with spinal dysraphism and neuropathic bladder dysfunction.

Patients with neuropathic bladder dysfunction secondary to spinal dysraphism may have gross spinal deformity, which makes assessing the urinary tract extremely difficult by ultrasonography or intravenous urography. The study included 50 patients (median age 33 years, range 19-52) with a median (range) Cobb's angle of 60 (0-240) degrees. No contrast medium was given but all patients received 20 mg of intramuscular frusemide 20-30 min before MRU.

Thirty-five patients had previous ultrasonography, during which only 42 kidneys and no ureters were visible. Of the 94 renal tracts, MRU visualized all kidneys and 86 (89%) ureters. There was good agreement amongst observers on assessing the kidneys and pelvicalyceal systems (kappa > or = 0.61) but only moderate agreement on evaluating the ureters (kappa < or = 0.61). There was disagreement on normality vs renal parenchymal scarring in 14 (15%) kidneys, about no dilatation vs dilatation of the pelvicalyceal system in 14 (15%) systems and about no dilatation vs dilatation of the ureter in 20 (22%) ureters. The overall quality of the MRU images was rated highly, with a mean (range) score of 4.6 (3-5).

MRU provides a reliable noninvasive technique for imaging the upper tract in patients who were previously difficult to investigate.