(A) Direct radionuclide cystography was performed with 0.5 mCi of Tc99m-pertechnetate. Dynamic posterior images reveal abnormal radiotracer appearing above the bladder on the right (arrow), increasing during the voiding phase. (B) A static posterior postvoid image demonstrates retention of radiotracer above the bladder on the right (arrow).

Differential Diagnosis

•  Vesicoureteral reflux (VUR): Activity should not be seen above the level of the bladder and if present indicates reflux.

•  Urinary contamination artifact: This is commonly seen but appears below the bladder, from leakage around the bladder catheter.

•  Urinary leak: This is much less likely and would appear outside the expected location of the bladder and collecting system.

Essential Facts

•  VUR is seen in 35 to 40% of children with urinary tract infection.