Core curriculum illustration: acute pyelonephritis.

This is the 26th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.aseronline.org/curriculum/toc.htm .