Hemorrhagic focal bacterial nephritis: findings on gray-scale sonography and CT.

Five patients with acute focal bacterial nephritis and hematuria had sonographic and CT findings atypical for renal infection. Sonographically, each presented with an echogenic focus in the renal parenchyma. Noncontrast CT images showed an area of increased density in the corresponding segment of the kidney in three patients, mixed high and low density in one patient, and low density alone in the remaining patient. It is proposed that these appearances result from the presence of hemorrhage at different stages, associated with focal infection. Venous compromise is suggested as the etiology.