Acute focal bacterial nephritis: emphasis on gray scale sonography and computed tomography.

The radiologic findings of acute focal bacterial nephritis in 13 patients are described. These include (1) focal swelling or mass on excretory urogram; (2) solid mass, often with echo amplitude lower than adjacent normal renal cortex on sonography; and (3) a poorly marginated, low density mass that exhibits patchy and inhomogeneous enhancement after intravenous contrast medium on computed tomographic scans. Serial sonograms are used to monitor the response of these patients to antibiotic therapy. The respective roles of sonography and computed tomography in the diagnosis and management of these patients are discussed.