barium swallow

Barium swallow studies are used to visualize the anatomy and function of the esophagus, and sometimes the pharynx, using barium sulfate as a radiopaque contrast agent. As the patient swallows, real-time fluoroscopic images capture the passage of contrast, allowing assessment of both structure and motility.

Clinical uses include: - **Achalasia**: Classic 'bird-beak' sign due to failure of LES relaxation and dilated proximal esophagus. - **Esophageal cancer**: 'Apple-core' lesion indicating an annular, constricting mass. - **Esophageal strictures**: Peptic strictures from chronic GERD appear as smooth, tapered narrowing. - **Zenker diverticulum**: Outpouching at Killian's triangle, seen as a posterior pharyngoesophageal pouch. - **Diffuse esophageal spasm**: 'Corkscrew esophagus' appearance due to uncoordinated contractions. - **Tracheoesophageal fistula** (in modified studies with water-soluble contrast preferred if perforation is suspected). - **Hiatal hernia**: Visualized as displacement of the gastroesophageal junction above the diaphragm.

Barium is preferred over water-soluble contrast (e.g., Gastrografin) for routine studies because it provides better mucosal detail; however, water-soluble contrast is used if esophageal perforation is suspected, since barium extravasation into the mediastinum can cause severe mediastinitis.

A modified barium swallow (videofluoroscopic swallow study) is often performed by speech-language pathologists to assess for aspiration risk in patients with oropharyngeal dysphagia (e.g., post-stroke patients).

Limitations: Barium swallow is less sensitive than endoscopy for detecting mucosal lesions like Barrett esophagus or early malignancy, and does not allow for biopsy. It is often used as an initial screening test before endoscopy (EGD) in the workup of dysphagia.