[Extravasation of contrast media in the excretory urogram]

Aetiology and diagnostic procedure of calyceal fornix rupture during intravenous urography are discussed. In the literature the fornix rupture is described as a spontaneous event--not so in the four cases presented. In two cases a sudden increase in intrapelvic pressure was due to an ureteric calculus, in the other cases an obstruction of the ureter was secondary to neoplasm. It is recommended to perform a CT as soon as a contrast medium extravasation in intravenous urography is diagnosed.