Periureteral inferior vena caval venous ring presenting as urinary obstruction.

The embryological development of the inferior vena cava (IVC) is complex, and thus the vena cava may undergo a large number of congenital anomalies. Periureteric venous ring is a rare developmental anomaly of IVC where the right ureter passes through a slit-like opening in a partially duplicated infrarenal IVC, resulting in dilatation of upper urinary tract. Split-bolus multidetector computed tomography technique is useful in detecting such vascular anomaly causing ureteric obstruction as it can clearly show the vascular and ureteric phase in a single acquisition.