Unstable bladder in children: functional evaluation by modified voiding cystourethrography.

A slightly modified technique for voiding cystourethrography was applied in 100 patients between 4 and 15 years of age and used to study uninhibited detrusor contractions in the so-called unstable bladder syndrome. Uninhibited detrusor contractions result in a slowing or cessation of the flow of contrast material into the bladder and a simultaneous minimal or marked opening of the bladder neck, with variable filling of the posterior urethra. Comparison of the radiologic findings with the results of urodynamic studies demonstrated an overall accuracy of 92%, sensitivity of 93%, and specificity of 90.7% for the radiologic technique.