Renal fibrosis: Prediction from acute pyelonephritis focus volume measuredat (TC)-T-99m dimercaptosuccinic acid SPECT

PURPOSE: To evaluate whether acute pyelonephritis lesion volume derived fro m acute technetium 99m (Tc-99m) dimercaptosuccinic acid (DMSA) renal single photon emission computed tomographic (SPECT) images is predictive of the d evelopment of subsequent renal fibrosis. MATERIALS AND METHODS: Children with acute pyelonephritis underwent Tc-99m DMSA renal SPECT during acute infection and 6-10 months later. At quantitat ive analysis, the volume of photopenic lesions and the ratio of radioactivi ty in the photopenic lesion to that in normal renal tissue were calculated. Sensitivity, specificity, and positive and negative predictive values were determined. RESULTS: Sixty-nine acute pyelonephritis foci in 44 children were analyzed. Thirty-seven (54%) of these lesions were normal on follow-up renal scans, while 32 (46%) developed scars. Significant differences in the photopenic l esion volume were found between the two groups (P <.001). When photopenic l esion volume indicated a positive diagnosis (<greater than or equal to>4.6- cm(3) lesion volume), sensitivity, specificity, positive predictive, and ne gative predictive values were 96.7%, 92.3%, 90.6%, and 97.3%, respectively. CONCLUSION: Quantitative analysis of acute DMSA renal SPECT findings is val uable in predicting renal fibrosis. The volume of an acute pyelonephritis l esion is useful in predicting the development of fibrosis.