Complete duplication of the right collecting system. The ureter draining the upper moiety is having an ectopic insertion at the prostatic urethra with resulting obstruction and marked back pressure changes of the right upper moiety and its ureter along its whole course. The obstruction is chronic manifested by the markedly dilated and tortuous right ureter draining the upper moiety. There is also thinning-out of the upper moiety renal parenchyma, also a sign of long term obstruction. at the first excretory phase scan there was delayed contrast excretion by the right upper moiety (an expected finding with obstruction and parenchymal atrophy), however the further delayed scan we see here showed average contrast excretion by the upper moiety. The ectopic ureter is seen inserted at the posterior aspect of the prostatic urethra.