A 38-year-old woman presents with a 3-month history of progressive dysphagia to solids and liquids, along with regurgitation of undigested food. Upper endoscopy shows a dilated esophagus with a smooth, tapered narrowing at the gastroesophageal junction and absence of peristalsis. There is no evidence of malignancy. Which imaging modality is most appropriate to confirm the diagnosis and assess disease severity?

Explanation

## Diagnosis: Achalasia The clinical presentation—progressive dysphagia, regurgitation of undigested food, dilated esophagus with smooth tapered narrowing at the GE junction, and absence of peristalsis on endoscopy—is pathognomonic for achalasia. ### Role of Barium Swallow in Achalasia **Key Point:** Barium swallow is the gold standard imaging modality for diagnosing achalasia and assessing disease severity. **High-Yield:** Barium swallow demonstrates the classic "bird's beak" appearance at the gastroesophageal junction—a smooth, tapered narrowing caused by failure of the lower esophageal sphincter (LES) to relax. The proximal esophagus is dilated, and there is an air-fluid level. ### Why Barium Swallow is Preferred | Feature | Barium Swallow | CT | EUS | MRI | |---------|---|---|---|---| | **Visualizes esophageal motility** | Yes (dynamic) | No | Limited | No | | **Shows bird's beak appearance** | Yes (classic) | No | No | No | | **Assesses severity (dilation, air-fluid level)** | Yes | Partial | No | Partial | | **Cost-effective** | Yes | No | No | No | | **Radiation burden** | Low | High | Minimal | None | | **First-line for diagnosis** | Yes | No | No | No | **Clinical Pearl:** Esophageal manometry is the definitive test for achalasia (elevated LES pressure, incomplete relaxation, aperistalsis), but barium swallow is the imaging investigation of choice because it provides morphologic confirmation and severity assessment. **Tip:** In NEET PG, when a question asks for "imaging investigation" or "radiologic diagnosis" in achalasia, the answer is barium swallow. Manometry is reserved for equivocal cases or when diagnosis is uncertain. [cite:Harrison 21e Ch 287]