## **Core Concept**
The question assesses knowledge of diagnostic methods for oesophageal varices, which are dilated submucosal veins in the oesophagus often associated with liver cirrhosis and portal hypertension. The best test should ideally be sensitive, specific, and minimally invasive.

## **Why the Correct Answer is Right**
Upper GI endoscopy is considered the gold standard for diagnosing oesophageal varices. It allows direct visualization of the varices, assessment of their size, and the presence of any stigmata of bleeding. This procedure is highly sensitive and specific for detecting varices and can also provide an opportunity for intervention if active bleeding is present.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Ultrasound, while useful for assessing liver morphology and portal vein flow, does not directly visualize oesophageal varices and is not as sensitive or specific as endoscopy for this purpose.
- **Option B:** CT abdomen with contrast can show signs suggestive of portal hypertension and may visualize large varices but is not as sensitive as endoscopy for detecting smaller varices or mucosal changes.
- **Option C:** This option seems to be missing but based on the context, if it were another imaging technique like MRI or a non-invasive test, it would likely not offer the same level of detail or direct visualization as endoscopy.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the presence of oesophageal varices is a significant risk factor for variceal bleeding, a complication with high mortality. Screening for varices with upper GI endoscopy is recommended in patients with cirrhosis. The Baveno VI consensus recommends that in patients with compensated advanced chronic liver disease (ACLD), endoscopy can be avoided if the patient has a liver stiffness measurement 150,000/μL.

## **Correct Answer:** . Upper GI Endoscopy.