There is no general agreement on which terms to use to report abnormal
ities on imaging studies in patients with kidney infection. The Societ
y of Uroradiology recommends a simplified nomenclature that is based o
n the traditional and widely understood term acute pyelonephritis. To
provide a framework for the simplified terminology, the authors review
the relevant pathophysiology with its imaging correlates and offer a
historic perspective on the terminology issues.