Posterior urethral valves - imaging findings

Key imaging findings in posterior urethral valves.
From Merrow AC Jr. Diagnostic Imaging: Pediatrics. 3rd ed. Elsevier; 2017.

1. Posterior urethral valves – imaging findings

2. fold / membrane just distal to prostatic urethra exclusively in males requires urgent endoscopic valve ablation

3. Best imaging tools prenatally fetal US fetal MRI postnatally voiding cystourethrogram – VCUG cystosonography – CSG

4. VCUG dilated posterior urethra with abrupt transition to anterior urethra at level of valve valve sometimes not seen  does not preclude diagnosis

5. VCUG signs of chronic bladder obstruction dilation wall trabeculation diverticula patent urachus

6. VCUG vesicoureteral reflux  hydroureteronephrosis  urinoma

7. CSG filling of bladder with US contrast imaging during voiding remove urethral catheter while voiding +/- transperineal approach or across pubic symphysis

8. CSG keyhole sign dilated bladder and posterior urethra chronic bladder obstruction thick trabeculated wall with diverticula kidneys hydroureteronephrosis cystic dysplasia urinoma

9. Remember VCUG – dilated posterior urethra with abrupt transition to anterior urethra CSG – key hole sign