What is the role of scintigraphy in the evaluation of acute pyelonephritis (kidney infection)?

Updated: Jul 01, 2021
  • Author: Tibor Fulop, MD, PhD, FACP, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc-DMSA) is almost as sensitive clinically as contrast-enhanced helical/spiral computed tomography (CECT) in detecting focal kidney abnormalities during acute pyelonephritis in adults. DMSA is a radiotracer that localizes to the kidney cortex. This modality is not used much in adults, however, because the findings are not specific; focal abnormalities may indicate abscess, cyst, infarct, pyelonephritis, or tumor. Additionally,99mTc-DMSA scintigraphy is much less available in the acute setting than CECT.

In children, however,99mTc-DMSA scintigraphy is the preferred study, because it involves less radiation exposure than CT scans. It is excellent for helping detect inflammation, scarring, and the distribution of function between kidneys.

In pediatric studies, diffusion-weighted magnetic resonance imaging (DW-MRI) compares favorably with 99mTc-DMSA scintigraphy. A study in seven children with acute pyelonephritis diagnosed on scintigraphy within 7 days of fever onset found that whole-body non-enhanced DW-MRI had 80% sensitivity and 100% specificity for detecting acute pyelonepritis lesions. [21]

Bosakova et al reported that non-contrast DW-MRI has higher sensitivity than 99mTc-DMSA scintigraphy for detecting acute inflammatory kidney lesions and multifocal lesions in pediatric patients with acute pyelonephritis. Their prospective study included 31 children aged 3-18 years with a first episode of febrile urinary tract infection and without a previously detected congenital urinary tract malformation, who were evaluated within 5 days of diagnosis. DW-MRI confirmed acute inflammatory changes of the kidney parenchyma, mostly unilateral, in all 31 patients, whereas scintigraphy detected inflammatory lesions in 22 (100% versus 71%; P = 0.002).  [22]

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