Crossed fused ectopic kidneys diagnosed by renal DTPA study

Technetium-99m DTPA renal imaging in a 15-year-old boy with a history of frequent urinary tract infections was performed and revealed two structures in the left abdomen: the first located superiorly maintained its reniform structure and had normal flow, extraction, and excretion. A second inferiorly located structure had poor extraction and excretion that did not improve appreciably with the administration of Lasix intravenously. A faint left ureter coursing ipsilaterally to the left bladder was seen; a prominent ureter originating from the lower moiety, crossing midline and coursing toward the right side of the bladder was also noted. These findings were consistent with crossed fused ectopic kidneys with an obstructed lower pole moiety. Subsequent retrograde and antegrade pyelograms and MRI provided further correlation.