Nucpaedia
Nucpaedia
Renal · DMSA

DMSA Cortical Scintigraphy

Snapshot

⁹⁹ᵐTc-DMSA binds functioning proximal tubular cells and is the reference standard for imaging the renal cortex — detecting acute pyelonephritis and permanent scarring, and quantifying differential function. It is used selectively in paediatric urinary-tract-infection pathways.

DMSA is retained in the cortex rather than excreted, so static images map functioning parenchyma. Photopenic areas represent acute inflammation or established scars.

CortexReference standard
ScarringPhotopenic defects
Split functionAccurate

When to image

  • Detecting renal scarring after urinary tract infection (especially in children).
  • Diagnosing acute pyelonephritis (cortical defects).
  • Quantifying differential cortical function.

How to read it

  • Focal photopenic defects with volume loss → scar; without volume loss/acute setting → acute pyelonephritis.
  • Report differential function from relative cortical uptake.
  • Correlate with the timing since infection.

Protocol

  • Static imaging ~2–3 h after injection (later if function is poor): posterior and posterior-oblique views; SPECT suggested in children where feasible, pinhole views in infants.
  • Assess scarring at least 6 months after the most recent UTI; an acute-phase scan for pyelonephritis is done within ~2 weeks of infection.
  • Ensure adequate counts for quantification.

Pitfalls

  • Acute defects can be reversible — repeat at 6 months to confirm true scars.
  • Duplex or rotated kidneys, hydronephrosis, cysts and pseudo-tumours (fetal lobulation, column of Bertin) mimic defects — correlate with ultrasound.
  • Poor positioning affects split-function accuracy.
Evidence & guidelines
  • SNMMI/EANM paediatric DMSA guideline update (Vali et al., Clin Transl Imaging 2022;10:173–184); SNMMI/EANM adult renal scintigraphy guideline (Blaufox et al., 2018).
  • DMSA is the reference standard for cortical scarring.
In depth
  • ⁹⁹ᵐTc-DMSA cortical imaging uses static images 2–4 h after injection (later if renal function is poor) in posterior and 30–35° posterior-oblique views, adding an anterior view when kidney number, shape or position is abnormal.
  • Relative (split) function is calculated from background-corrected counts in each kidney, using the geometric mean of anterior and posterior views when kidney depths differ; a markedly scarred, contracted kidney may contribute only a small fraction of total function.
  • Scars are focal reduced-uptake areas with volume loss and an irregular/disrupted cortical outline.
  • A small, contracted kidney with markedly reduced uptake indicates severe global cortical impairment.
  • Pinhole collimation or SPECT can show small cortical defects better than parallel-hole planar imaging, but there is no consensus that SPECT adds clinical value, and it may increase false-positive findings.
  • Correlate defects with anatomical imaging (usually ultrasound, or CT/MRI) to distinguish scarring from pseudo-tumours such as fetal lobulation, a dromedary hump or a prominent column of Bertin, and from cysts or masses.

Sources: SNMMI/EANM renal scintigraphy guideline 2018 (PMID 30167801) · EANM paediatric DMSA guideline, Piepsz et al. 2001 (PMID 11315615) · Piepsz et al. 2001 (PMID 11315615)

Practise with a case
← BackRenal