COMPARATIVE STUDY OF INDIUM-111 LEUKOCYTES AND NEPHROSONOGRAPHY FOR DETECTION OF EXPERIMENTAL PYELONEPHRITIS IN DOGS

Nephrosonography was compared to In-111 WBC for detection of experimentally induced pyelonephritis in 12 dogs. Nephrosonography was performed during the acute and chronic phase of pyelonephritis in all dogs. Sonographic abnormalities were found in all infected kidneys imaged early after infection. In the chronic phase of pyelonephritis, the sonographic abnormalities had decreased in severity in 9 kidneys, increased in severity in 2 kidneys, and had resolved in 2 kidneys. After histopathologic evaluation, eleven of fifteen kidneys (73%) with pyelonephritis had been identified by sonography. The In-111 WBC scan was performed during the acute phase of pyelonephritis in 9 dogs and during the chronic phase in all dogs. During the acute phase of pyelonephritis, the WBC scan was positive in 8 of the 9 dogs (89%) on images acquired 24 and 48 hr after injection of the labelled WBC. During the chronic phase of pyelonephritis, the WBC scan was negative in all 12 dogs. The sensitivity of the In-111 WBC scan was poor compared to nephrosonography for detection of chronic pyelonephritis. In this study, optimal detection of renal infection/pyelonephritis by In-111 WBC may be dependent on the presence of clinical signs and leukocytosis in dogs. Even when leukocytosis is present, the In-111 WBC may fail to accumulate in the kidney in dogs with pyelonephritis, particularly if no clinical signs (fever, depression, inappetence) are present.