Segmental nephrogram

An obstructive nephrogram involving the entire kidney owing to an acute ureteral obstruction is a well known phenomenon. A nephrogram occurring in half of the kidney (segmental nephrogram) has not been described previously. A patient who presented with acute left renal colic is described. An excretory urogram revealed a segmental nephrogram, which was subsequently found to be caused by acute calculous obstruction of 1 of the 2 limbs of a bifid pelvis. The stone was removed through a left pelviotomy.