<prompt> Investigation of choice for Posterior urethral valves:Micturating Cystourethrography MCUUltrasoundIntravenous PyelographyRetrograde urethrography  <response>: Ans. a MCU. Ref. Sutton Radiology 7th ed. 1017, 1061- MCU is IOC for PU valve and VUR.Posterior urethral valves PUV Varying degree of chronic urethral obstruction due to fusion and prominence of plicae colliculi, normal concentric folds of urethra. Usually located in posterior urethra just distal to the level verumontanum.c; It is the most common cause of severe obstructive uropathy in infants and children. MCU is gold standard in diagnosis of PUV. Rx: Cystoscopic fulguration of the valves.Three types of PUV are described : 