Comparative clinical studies have shown renal cortical scintigraphy, using technetium-99m (99mTc)-labeled
glucoheptonate or
dimercaptosuccinic acid (
DMSA), to be significantly more sensitive than either intravenous pyelography or renal sonography in the diagnosis of acute
pyelonephritis. However, due to uncertainties about the diagnostic accuracy of the clinical and laboratory parameters used in these studies, true sensitivity of renal cortical scintigraphy was unknown. Therefore, we evaluated the accuracy of [
99mTc]DMSA scintigraphy in the diagnosis of experimentally induced acute
pyelonephritis in piglets using strict histopathologic criteria as the standard of reference. The sensitivity and specificity of the
DMSA scan for the diagnosis of acute
pyelonephritis were 91% and 99%, respectively, with an overall 97% agreement between the scintigraphic and histopathologic findings. Based on the results of this experimental study, we used the [
99mTc]DMSA scan as the standard of reference for the diagnosis of acute
pyelonephritis, and conducted a prospective clinical study of 94 children hospitalized with the diagnosis of acute febrile
urinary tract infection (UTI). The aims of this study were (1) to determine the relationship among
vesicoureteral reflux, P-fimbriated Escherichia coli, acute
pyelonephritis, and renal
scarring, and (2) to evaluate the diagnostic reliability of the clinical and laboratory parameters commonly used in the diagnosis of acute
pyelonephritis. We documented acute
pyelonephritis in 62 (66%) of 94 patients.
Vesicoureteral reflux was demonstrated in 29 (31%) of the total group and in only 23 (37%) of 62 patients with acute
pyelonephritis. The prevalence of P-fimbriae in the E coli isolates was 64% in the patients with acute
pyelonephritis and 78% in those with a normal
DMSA scan. Even in patients without reflux, P-fimbriae were found in 71% of isolates from the patients with acute
pyelonephritis and in 75% of those with a normal renal scan. Follow-up
DMSA scans were obtained in 33 patients with acute
pyelonephritis in 38 kidneys. We found complete resolution of the acute inflammatory changes in 58% of the involved kidneys and renal
scarring in the remaining 42%, including 40% of the kidneys associated with reflux and 43% of those without reflux.(ABSTRACT TRUNCATED AT 400 WORDS)