Investigation of choice for Zenker’s diverticulum is:
**Core Concept**
Zenker's diverticulum is a type of esophageal diverticulum that occurs in the upper esophagus, specifically at the cricopharyngeal junction. It is a false diverticulum, meaning it only involves the mucosa and submucosa of the esophagus, and not the muscular layer. The cricopharyngeal muscle is often hypotonic or dysfunctional, leading to the formation of the diverticulum.
**Why the Correct Answer is Right**
The investigation of choice for Zenker's diverticulum is a **barium swallow study**, also known as an esophagram. This radiographic test involves swallowing a barium sulfate solution, which allows for visualization of the esophagus and any abnormalities, such as the diverticulum. The barium will accumulate in the diverticulum, making it visible on the X-rays. This test is particularly useful for diagnosing Zenker's diverticulum, as it can show the size and location of the diverticulum, as well as any associated symptoms such as dysphagia or regurgitation.
**Why Each Wrong Option is Incorrect**
**Option A:** CT scan is not the primary investigation for Zenker's diverticulum, as it may not provide detailed visualization of the esophagus and the diverticulum.
**Option B:** Upper GI endoscopy may be used to visualize the esophagus and the diverticulum, but it is not the investigation of choice due to the risk of perforation and the fact that it may not provide as much detail as a barium swallow study.
**Option C:** MRI is not typically used for diagnosing esophageal diverticula, as it is not as sensitive as barium swallow studies for visualizing the esophagus and any associated abnormalities.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that Zenker's diverticulum often presents with symptoms such as dysphagia, regurgitation, and aspiration pneumonia, and that a barium swallow study is the gold standard for diagnosing this condition.
**Correct Answer:** C.