It is found in ~10% of the population 2.
An extrarenal pelvis usually appears dilated, erroneously suggesting obstructive pathology. Subsequent investigation with CT usually clarifies a false interpretation on ultrasound.
- a normal extrarenal pelvis will demonstrate normal renal cortical thickness, bilateral symmetrical contrast excretion and normal appearing calyces 3
After evaluation with ultrasound and/or CT/MRI, if there is still confusion whether a dilated renal pelvis is obstructed or not, renal scintigraphy can clarify
- 1. Dunnick R, Sandler C, Newhouse J. Textbook of Uroradiology. Lippincott Williams & Wilkins. (2012) ISBN:1451109164. Read it at Google Books - Find it at Amazon
- 2. Brant WE, Helms CA. Fundamentals of Diagnostic Radiology. Lippincott Williams & Wilkins. (2007) ISBN:0781761352. Read it at Google Books - Find it at Amazon
- 3. Siegel MJ. Pediatric body CT. Lippincott Williams & Wilkins. ISBN:078177540X. Read it at Google Books - Find it at Amazon