Robert L. Lebowitz, M.D. Children' s Hospital, Harvard Medical School Boston, Massachusetts

UPJ Obstruction with Coexisting Reflux

Prenatal diagnosis of hydronephrosis confirmed on postnatal ultrasonography. Post-op VCUG showed the three hallmarks of the coexistence of UPJ obstruction and reflux:

1. Delay in passage of refluxed contrast material from ureter through narrowed UP junction into dilated pelvis. The refluxed material stops at the UPJ before entering the pelvis. (Figure 1)
2. Dilution of refluxed contrast agent by non-opaque, stagnant urine trapped in dilated renal pelvis. The density of contrast is less in the dilated pelvicaliceal system than in the ureter or in the opposite pelvis - the patient had left Grade II reflux. (Figure 2)
3. Trapping of contrast material shown on drainage films. The left side drains, as does the right ureter, but the contrast remains in the dilated right pelvicaliceal system above the point of narrowing at the UP junction. (Figure 3)