What nuclear medicine esophageal studies are available? How are they used?
• Esophageal motility study: The evaluation of esophageal dysmotility should begin with assessment for anatomic abnormalities using endoscopy, barium swallowing study, or CT. This is typically followed by manometry if an anatomic cause is not identified. A nuclear medicine study is performed if a diagnosis is still uncertain. Rapid sequential imaging in either the supine or upright position after ingestion of 99m Tc sulfur colloid in water is performed with additional subsequent dry swallows during imaging. Esophageal motility studies are also useful in evaluation of response to therapy for dysmotility and achalasia.
• Esophageal reflux study: This study is performed by serial imaging of the esophagus after the patient drinks acidified orange juice containing 99m Tc-sulfur colloid with subsequent serial inflation of an abdominal binder. Although less sensitive than 24-hour pH monitoring, the test is more sensitive than barium studies and can be used as a screening study or evaluation of response to therapy.
• Pulmonary aspiration studies: These studies are performed by imaging the chest after oral administration of 99m Tc-colloid in water or formula in infants. Activity in the lungs is diagnostic of aspiration. Although sensitivity is low, it is likely higher than that of radiographic contrast studies. The test has the advantage of easy serial imaging to detect intermittent aspiration.