Question

Which one of the following conditions is diagnosed by Tc99 pertechnetate scintigraphy?

• A. Pharyngeal diverticulum
• B. Duodenal diverticulum
• C. Meckel's diverticulum
• D. Colonic diverticulum

Hint:

Think about which diverticulum can contain ectopic gastric tissue that takes up the tracer.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks which of four types of diverticulum is diagnosed with a technetium-99m pertechnetate scan.

Step 2: Key Concept or Approach:
Tc99m pertechnetate is taken up selectively by mucin-secreting gastric mucosa. A scan will therefore light up wherever gastric-type mucosa is present, even if it lies outside the stomach.

Step 3: Working Through the Options:
A pharyngeal diverticulum, such as a Zenker's diverticulum, is a pulsion outpouching at the pharyngo-oesophageal junction and is diagnosed with a barium swallow or endoscopy, not a nuclear scan, since it contains no gastric mucosa. A duodenal diverticulum is usually an incidental finding on barium studies, endoscopy, or CT and again has no ectopic gastric tissue to take up the tracer. A colonic diverticulum is part of diverticular disease and is diagnosed by colonoscopy, barium enema, or CT, also without gastric mucosa involved. Meckel's diverticulum is a true congenital outpouching of the ileum, a remnant of the vitellointestinal duct, and it frequently contains ectopic gastric mucosa, sometimes along with pancreatic tissue. This ectopic gastric mucosa takes up pertechnetate the same way normal gastric mucosa does, so the diverticulum shows up as a focal area of increased uptake on the scan, which is why this study is often simply called a Meckel's scan.

Step 4: Conclusion:
Meckel's diverticulum is the condition diagnosed by Tc99 pertechnetate scintigraphy.