Paediatric Meckel’s Scan
Snapshot
In children with painless lower-GI bleeding, the ⁹⁹ᵐTc-pertechnetate Meckel’s scan detects ectopic gastric mucosa within a Meckel’s diverticulum — the most common cause of lower-GI haemorrhage in previously healthy infants. Overall sensitivity is ≈85% (specificity ≈95%), higher than in adults; H2-blocker/PPI pre-treatment can improve sensitivity but is not considered necessary.
Pertechnetate is concentrated by gastric mucosa, so ectopic mucosa in a Meckel’s diverticulum appears as a focus that rises in parallel with the stomach.
Ectopic mucosaPertechnetate
PaediatricHigher yield
RLQ focusParallels stomach
When to image
- Painless lower-GI bleeding in a child with negative endoscopy.
- Suspected Meckel’s diverticulum.
How to read it
- A focus appearing with, and rising alongside, gastric activity (usually right lower quadrant).
- Empty the bladder and use lateral views to exclude urinary activity.
- No ectopic gastric mucosa → false negative.
Protocol
- Fasting 3–4 h if possible (not mandatory); optional H2-blocker/PPI pre-treatment.
- Weight-based dose (1.85 MBq/kg, minimum 9.25 MBq); dynamic imaging (1 frame/30–60 s) for at least 30 min, up to 60 min.
- Post-void/lateral views.
Pitfalls
- Diverticula without gastric mucosa are missed.
- Urinary tract and inflammatory activity cause false positives.
- Recent in vivo red-cell labelling (stannous pyrophosphate) or perchlorate reduces uptake (false negative).
Evidence & guidelines
- SNMMI/EANM Meckel diverticulum scintigraphy guideline 2.0 (Spottswood et al., J Nucl Med Technol 2014;42:163–169).
- Higher yield in the paediatric population.
Practise with a case
- Painless rectal bleeding in a 3-year-old boy · Beginner