Blunt abdominal injury resulting in left superior pole collecting system injury and urine leak. 

A few observations/teaching points:

• Outside facility CT inappropriately did NOT have delayed images. Trauma scans positive for any significant injury should get delayed images, particularly in the setting of hemoperitoneum. As a result, the urine leak was not immediately appreciated. 
• Clot filling and obstructing the collecting system can be fairly subtle, and is best appreciated with delayed, excretory phase images. 
• A small urine leak (such as this one) was successfully managed non operatively. Ureteroscopy performed on day 2 showed resolution of the clot and mild hydronephrosis, with temporary double J stent placed to facilitate healing.