What's the most likely diagnosis?
- 36 year-old undergoing retrograde pyelogram

Left Kidney-Retrograde Pyelogram
- Renal laceration
- Hepato-renal fistula
- Pyelovenous backflow
- Retroperitoneal fibrosis
- Staghorn calculus
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Answer:
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3. Pyelovenous backflow
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Pyelovenous Backflow
General Considerations
- Refers to the retrograde flow of contrast material out of the intrarenal collecting system due to a small rupture of a calyceal fornix
- Almost always seen with increased pressure in the collecting system such as from
- Retrograde pyelography
- Antegrade pyelography (urogram), due to obstruction of the collecting system almost always by a ureteral calculus
- Obstruction is usually in the ureter
- Rupture decompresses collecting system
- Rarely, from vesico-ureteral reflux
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