IMPORTANT: We currently have a number of bugs related to image cropping and are actively trying to resolve them. In the meantime, we have disabled cropping. Apologies for any inconvenience. Stay informed: radiopaedia.org/chat

Parapelvic cysts and PUJ obstruction

Case contributed by Frank Gaillard
Diagnosis certain

A three-phase CT study of the kidneys has been performed (corticomedullary, nephrographic and excretory) phases.  The excretory phase equates to a CT-IVU, typically undertaken at 8-10 minutes following IV contrast administration.

The pelvis of both kidneys are expanded by water density spaces. The right kidney is atrophic with a reduced bipolar diameter (BPD). The left is larger. The cortex of both kidneys enhances normally. 

On the delayed excretory phase images, the kidneys behavior differently. On the right contrast pools dependently within a distended renal pelvis, consistent with a PUJ obstruction. On the left the calyces are outlined, compressed by numerous para-pelvic cysts (which do not contain contrast). 

Case Discussion

This case elegantly demonstrates how difficult it can be to distinguish a dilated renal pelvis from parapelvic cysts without a delayed phase. 

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.