Case Author(s): Brigid Gordon, MD and Henry Royal, MD , 08/04/96 . Rating: #D2, #Q4

Diagnosis: Pyelonephritis

Brief history:

2 year old female with fevers, pyuria, and leukocytosis.


Posterior views of both kidneys using LEAP collimator

View main image(rs) in a separate image viewer

View second image(rs). Pinhole images of the kidneys

(Upper row LPO and RPO, lower row posterior views)

Full history/Diagnosis is available below

Diagnosis: Pyelonephritis

Full history:

2 year old female with fever, leukocystosis, and pyuria with negative blood and urine cultures. No prior documented urinary tract infections. Because of persistent fevers despite antibiotics, a renal ultrasound was obtained prior to the renal nuclear scan. The ultrasound suggested a focus of increased echogenicity in the upper pole of the right kidney, but without cortical thinning to suggest prior scarring (sonogram not shown).




Immediate blood flow and static images (not included) demonstrated decreased flow and tracer uptake to the upper pole of the right kidney. The posterior images (provided above) were obtained 3 hours after the injection of the tracer. Both kidneys are normal in size and location. However, there is a cortical defect in the upper pole of the right kidney that corresponded to the abnormality on the immediate and static views.


Pyelonephritis, scar, and solid renal masses can produce decreased uptake of this radiopharmaceutical. In the case of infection or pyelonephritis, it is postulated that there is an inactivation of the transport mechanism for the radiopharmaceutical across the cell membrane into the tubular cells. This results in decreased localization of the tracer (i.e. cortical defect) at the site of infection. TC99m-DMSA imaging provides visualization of the renal parenchyma without interference from retention of tracer in the collecting system.

Major teaching point(s):

Cortical defects caused by infection.

Differential Diagnosis List

Differential includes both infection, scar and renal masses.

ACR Codes and Keywords:

References and General Discussion of Renal Scintigraphy (Anatomic field:Genitourinary System, Category:Inflammation,Infection)

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Case number: rs010

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