Delayed contrast enhancement in acute focal bacterial nephritis: CT features.

Computed tomography was performed in seven patients with acute pyelonephritis 6 h after the administration of contrast medium. Four patients revealed patchy wedge-shaped areas of contrast enhancement. The scans immediately after contrast medium administration showed decreased attenuation in these wedge-shaped areas. These results suggest that CT performed hours after contrast medium administration may reveal delayed enhancement in a significant number of patients with acute pyelonephritis.