Published in:
01-01-2020 | Urography | Classics in Abdominal Radiology
The “balloon on a string” appearance of the renal collecting system and ureter
Published in: Abdominal Radiology | Issue 1/2020
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The “balloon on a string” (Fig. 1) appearance of the renal collecting system and ureter is a classic imaging sign applied to ureteropelvic junction obstruction (UPJO) [1]. This sign may be seen with traditional radiographic evaluation of the kidney, such as with IV urography (excretory urography) or retrograde pyelography (Fig. 2), but it can also be seen with CT urography (Fig. 3) or MR urography.
Fig. 1
A balloon on a string (thanks to Henry Morgan-Panditaratne for his help with this photograph)
Fig. 2
Retrograde pyelogram of the left kidney, performed for gross hematuria in an adult male, showing the “balloon on a string” appearance of UPJO
Fig. 3
Volume-rendered reconstruction from a CT urogram in an adult female patient, performed to evaluate hydronephrosis and microhematuria, revealing the “balloon on a string” appearance of an unsuspected right-sided UPJO
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