Aim: Acute focal pyelonephritis (AFP) is a variant of pyelonephritis in which single or multiple discrete areas show changes of inflammation. The reported sonographic appearances of AFP are varied but are typically described as being echopoor. The purpose of this study was to review the sonographic appearances of AFP and attempt to explain the range of findings by correlation with clinical details.
Materials and methods: We reviewed retrospectively the sonographic findings and medical records of 17 cases of AFP. The study group consisted of 13 women and four men (mean age 20 years). Lesions were designated as echogenic, echopoor or of mixed echogenicity as compared to the adjacent renal cortex, and to the liver or spleen.
Results: The abnormal areas were echogenic in 12 patients, echopoor in three and of mixed echogenicity in two. An attempt was made to explain the variation in appearances by correlation with clinical details including the patient's age, the duration of symptoms, the length of antibiotic treatment and the presence of haematuria.
Conclusion: Areas of acute focal pyelonephritis may be echogenic, echopoor or of mixed echogenicity. Our data would suggest that areas of increased echogenicity are more common. There is no discernible correlation with clinical findings.
Copyright 2002 The Royal College of Radiologists.