Misleading appearances of the bladder on pediatric genitourinary imaging

The authors reviewed images of the bladder on 100 consecutive Tc-99m DTPA pediatric renograms for any abnormal distribution of radionuclide or asymmetry suggestive of anatomic bladder abnormality. The results were correlated with radiographic contrast voiding cystourethrograms and ultrasound examination. Of 81 patients with adequate bladder imaging, 50 (62%) had symmetric and uniform distribution of radioactivity within the bladder. Thirty-one patients (38%) had a sufficiently abnormal bladder appearance to suggest anatomic abnormality. Of these 31 patients, 27 had contrast cystograms and ultrasound evaluation; only one (4%) had a proven bladder abnormality which correlated with the abnormal scintigraphic appearance. The appearance of the bladder on pediatric genitourinary imaging is a nonspecific and unreliable indicator of anatomic bladder abnormality.