Duplex kidney

MCU of a boy with a left-sided duplex system demonstrates contrast outlined a large filling defect within the base of the urinary bladder in keeping with a large ureterocele which appeared slightly to the left of the midline.

On initial voiding, there was reflux of contrast into a dilated, tortuous lower pole moiety ureter with contrast outlining dilated renal pelvis and multiple lower pole calyces showing preserved papillary impressions. No definite reflux was identified within the upper pole moiety ureter.

No right-sided vesicoureteric reflux was seen (not shown).

 Tc-99m MAG3 (59 MBq)

There was decreased perfusion to the entire left kidney and absent perfusion to the upper pole area of left kidney. Perfusion in the right kidney was homogeneous. Parenchymal activity in the right kidney was normal. There was only a functional area in what appeared to be lower pole moiety of left kidney. A delayed image did show visualization of minor pooling in what looks like lower pole moiety of the left kidney and ureter down to the bladder.

There was 76% activity in the right kidney and 23% in the lower pole moiety of the left kidney. The upper pole moiety was assigned 1% activity. Renogram curve for the right kidney showed tracer uptake and excretion. The lower pole moiety showed a lower peak and did not have a significant excretory slope although on visual images there was some drainage noted with no significant retention until the final image which could even suggest reflux as this was known from previous VCUG.

IMPRESSION: Non-functioning upper pole multicystic dysplastic moiety of left kidney. The remaining lower pole of the left kidney has decreased perfusion and function but no marked delay in drainage. Visualization of the left ureter on delayed image could be due to reflux. Normal functioning right kidney.