What is a Biphasic Esophagram?
A biphasic esophagram is a fluoroscopic barium study that combines upright double-contrast views (using high-density barium) with prone single-contrast views (using low-density barium) to simultaneously evaluate both structural abnormalities and functional motility disorders of the esophagus. 1
Technical Components
The examination consists of two distinct phases that complement each other:
Double-contrast phase (upright): Uses high-density barium suspension to coat the esophageal mucosa, optimizing detection of mucosal abnormalities including inflammatory diseases (esophagitis, erosions, ulcers), fine nodularity, and neoplastic lesions (carcinoma) 1, 2
Single-contrast phase (prone): Uses low-density barium suspension that the patient continuously drinks while lying prone, optimizing detection of structural abnormalities including hiatal hernias, lower esophageal rings (Schatzki rings), and strictures 1, 2
Mucosal-relief views: May be obtained with either barium density to provide additional anatomic detail 1, 2
Clinical Utility and Diagnostic Performance
The biphasic technique is the preferred imaging procedure for retrosternal dysphagia because it permits detection of both structural and functional abnormalities:
Structural Lesions Detected
- Esophageal carcinoma: 96% sensitivity for diagnosing cancer of the esophagus or gastroesophageal junction 1
- Lower esophageal rings: Detects approximately 95% of rings (compared to only 76% detection rate with endoscopy), because prone single-contrast views provide better distal esophageal distention than upright views 1
- Peptic strictures: Approximately 95% sensitivity, sometimes revealing strictures missed by endoscopy 1
- Reflux esophagitis: Combined biphasic technique achieves 88% sensitivity (compared to 77% for single-contrast alone and 80% for double-contrast alone) 1, 3
Functional Abnormalities Detected
- Esophageal motility disorders: 80-89% sensitivity for diagnosing achalasia and diffuse esophageal spasm compared to esophageal manometry 1, 4
- Gastroesophageal reflux: Can demonstrate reflux events with provocation 1
Advantages Over Alternative Studies
The biphasic esophagram is superior to single-contrast esophagram alone because the double-contrast phase provides superior mucosal detail that single-contrast technique cannot achieve 1
The biphasic esophagram outperforms endoscopy for certain structural lesions, particularly lower esophageal rings (95% vs 76% detection) and can reveal peptic strictures missed at endoscopy 1
The biphasic esophagram is more comprehensive than modified barium swallow alone because modified barium swallow (videofluoroscopic swallowing study) does not evaluate the thoracic esophagus or gastric cardia, whereas the biphasic esophagram provides complete esophageal assessment 1
Clinical Indications
The American College of Radiology recommends biphasic esophagram as the preferable initial imaging procedure for:
- Retrosternal dysphagia (sensation of blockage between thoracic inlet and xiphoid process) 1
- Unexplained oropharyngeal dysphagia when combined with pharyngeal imaging, since distal esophageal or gastric cardia lesions can cause referred dysphagia to the pharynx 1, 5, 4
- Suspected acid reflux, esophagitis, or peptic ulcer disease presenting with epigastric pain 1
- Immunocompromised patients with dysphagia or odynophagia, where it can guide management and identify infectious esophagitis patterns 1
Important Clinical Caveats
Patient cooperation is required for optimal biphasic examination—elderly, debilitated, or obese patients who cannot fully cooperate may require single-contrast technique only 1
Endoscopy remains superior for detecting mild reflux esophagitis and other subtle forms of esophagitis, and is necessary for tissue diagnosis when biopsy specimens are required 1
Complete esophageal evaluation is essential even when pharyngeal symptoms predominate, as one-third of patients with dysphagia complaints have abnormalities only in the esophagus 1