CT and sonography of severe renal and perirenal infections.

Twelve patients with urosepsis and severe renal or perirenal infections were evaluated with both computed tomography (CT) and sonography. Six patients had nine proven renal or perirenal abscesses larger than 2 cm in diameter. One patient had multiple microabscesses smaller than 1 cm. Five patients had CT or sonographic evidence of focal or multifocal bacterial nephritis. Computed tomography correctly diagnosed all renal (six) and perirenal (three) abscesses. Sonography was falsely negative in a patient with multiple microabscesses and in another patient with a gas-forming perinephric abscess. In one patient with four bilateral renal abscesses, sonography correctly diagnosed only one of the abscesses. In the five patients with focal or multifocal bacterial nephritis, CT demonstrated poorly defined, poorly enhancing lesions in all cases. Sonography was normal in three of these patients. Although this report is based on a limited experience, computed tomography seems to be the more sensitive method of evaluating severe renal and perirenal infections.