Crossing renal vessel causing ureteropelvic junction obstruction-report of two cases

Ureteropelvic junction [UPJ] obstruction is caused by the presence of an aperistaltic dysplastic segment at the UPJ. Besides this intrinsic aetiology, extrinsic factors, mainly crossing vessels, may be the causative factor. The controversy regarding the functional significance of vessels crossing at the UPJ is not a new one, though this debate has been resurrected in recent years because of improved detection due to advent of advanced imaging techniques like multidetector row computed tomography [MDCT] and fast magnetic resonance imaging. We present two similar cases where MDCT proved the crossing renal vessel [CRV] to be the cause for UPJ obstruction