Gas in the kidney: CT findings.

Gas in the renal parenchyma is a rare finding seen best with computed tomography (CT). It can be encountered in a wide range of clinical conditions, some of them life-threatening like emphysematous pyelonephritis, whereas in others, it may represent a postoperative or procedure outcome. The latter are not usually a clinical emergency (for example, after nephrostomy insertion or in a urinary intestinal connection). Due to the increasing use of abdominal CT examinations, radiologists, especially in emergency setting, should be aware of this rare finding and be familiar with its differential diagnosis.