Case Author(s): Eric Hutchins, M.D. and Jerold Wallis, M.D. , 09/23/04 . Rating: #D., #Q.

Diagnosis: Vesicoureteral Reflux

Brief history:

4 month-old boy recently treated for a urinary tract infection.

Images:

Initial posterior images.

View main image(rs) in a separate image viewer

View avi cine image (1 meg) Posterior images after furosemide administration

View third image(rs). Time/activity curves and analysis

View fourth image(gu). Anterior image of voiding cystourethrogram

Full history/Diagnosis is available below

Diagnosis: Vesicoureteral Reflux

Full history:

4 month-old boy who was treated 2 months previously for a urinary tract infection presents for diuretic renal scintigraphy after an ultrasound demonstrated moderate left and mild right hydronephrosis.

Radiopharmaceutical:

1.1 mCi Tc-99m MAG3 i.v. and 7.7 mg furosemide i.v.

Findings:

Initial 20 minutes of imaging demonstrates the right kidney to be smaller than the left. There is normal uptake and excretion of tracer by the left kidney, with retention of tracer in the left collecting system. There is lesser (but prompt) uptake and excretion of tracer by the right kidney. There is also mild retention of radiotracer in the right collecting systems.

Renogram after furosemide administration shows prompt clearance of residual pelvicaliceal activity of the left. On the right, there are intermittent episodes of increasing radiotracer activity in the collecting system consistent with marked vesicoureteral reflux. The reflux is most evident on cine images, and was surprisingly difficult to see on static images (not shown). This was due to the fact that the static images were reframed to 2 minute frames for filming purposes (as opposed to the 20-second frames available for cine).

Time/activity curves and analysis demonstrate that the right kidney contributing 28% and the left kidney 72% of total renal function. Also the T1/2 of clearance of residual activity in the left renal collecting system after furosemide administration is 6 minutes, normal, and suggesting no obstruction on the left.

Radiograph taken during a VCUG shows grade V vesicoureteral reflux on the right.

Discussion:

Primary vesicoureteral reflux is most commonly due to an abnormal insertion of the distal ureter into the bladder wall. In 95% of affected children, it resolves spontaneously by 6 years of age.

When performing a renogram on an infant or young child, a Foley catheter should be in place to drain urine from the bladder. In this patient the Foley catheter was present but not functioning properly, thus the patient's marked vesicoureteral reflux is well demonstrated.

Major teaching point(s):

When performing a renogram in a young child or infant, if reflux is a possibility, place a Foley catheter before the examination.

Viewing post-diuretic images in cine format is helpful to detect reflux.

ACR Codes and Keywords:

References and General Discussion of Renal Scintigraphy (Anatomic field:Genitourinary System, Category:Normal, Technique, Congenital Anomaly)

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Case number: rs034

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