This most commonly used method of investigating the esophagus evaluates both structural lesions and motor disorders. It is the single most important test in evaluating patients with dysphagia. Proper communication between physician and radiologist is vital. Videotaping the barium swallow allows for playback and slow-motion review. This is very helpful in assessing the rapid events of the oropharyngeal phase of swallowing. Use of marshmallows, barium-coated cookies and different consistencies of barium further assesses swallowing disorders, as delays in transport may not be apparent with simple liquid barium. The disadvantage of barium x-rays is that they are relatively insensitive in detecting mucosal disease, even if air contrast technique is added.

Fiberoptic endoscopy directly visualizes the esophageal mucosa as well as other areas of the upper gastrointestinal tract. Its direct view is superior to barium x-rays for assessing mucosal disease of the esophagus, and the esophagoscope permits assessment of structural lesions that are identified. Furthermore, pinch biopsies and/or brush cytology of specific lesions are easily obtained through the endoscope. Microscopic evidence of esophagitis may be found even when the mucosa looks grossly normal. Endoscopy is the single most useful test in the evaluation of patients with reflux symptoms, as it permits one to establish the presence or absence of esophagitis or Barrett's esophagus (Section 7.3). Endoscopy gives little reliable information regarding esophageal function.

This tests the sensitivity of the patient's esophagus to acid perfusion. A tube is placed into the distal esophagus and saline, acid and then antacid are infused sequentially, with the patient kept unaware as to what is being administered. The patient is questioned periodically about the presence or absence of symptoms and their quality. This test is useful in determining whether a patient's atypical chest or epigastric pain is secondary to acid reflux. The test is positive if the patient's presenting pain is reproduced during acid perfusion and relieved by antacid perfusion.

This involves recording intraluminal pressures at multiple sites along the esophagus (Figure 1). The most commonly used method involves a perfused multilumen catheter bundle with side holes at 5 cm intervals. Each catheter is connected to a pressure transducer, which in turn is attached to a physiograph. LES pressure and swallow-induced LES relaxation are measured, as are pressure responses to swallowing at several esophageal sites. Pharyngeal peristalsis and UES function can also be measured. Esophageal manometry is the "gold standard" in the assessment of esophageal motor disorders. Motor dysfunction, however, may be intermittent and therefore not detected at the time of the study. Manometry is now commonly combined with provocative tests (acid perfusion, balloon distention and/or pharmacological stimulation of the esophagus with bethanechol or edrophonium) in an attempt to evoke abnormal contractions and reproduce the patient's chest pain (Section 11).

These are performed using a pH electrode passed via the nose or mouth into the distal esophagus. The traditional short-duration study measures acid reflux events (pH drop to < 4) after various postural maneuvers. This has now been largely replaced by a miniature system that with computer assistance allows 24-hour ambulatory studies. The results of this test are compared to a healthy control population to determine whether an abnormal degree of gastroesophageal reflux is present. The test is most useful, however, in determining whether atypical symptoms coincide with acid reflux events, and in objectively assessing the response to therapy in patients with refractory symptoms.

These assess either gastroesophageal reflux or esophageal transit. In the latter instance, food or fluid labeled with a radioisotope is swallowed and gamma camera scanning is performed over the chest. Computer programs measure transit time in the upper, middle and lower thirds of the esophagus. This has been reported to be a sensitive way of detecting motor dysfunction in patients with dysphagia. It may therefore be a useful screening test, but fails to give reliable information concerning the type of motor disorder present. Gastroesophageal reflux can be quantitated by having the patient ingest the radioisotope and then scanning over the chest and upper abdomen. Binders are placed over the abdomen to increase intra-abdominal pressure; reflux is present if the isotope is seen to travel back up into the esophagus. The role of this test in the assessment of patients with reflux disease remains to be defined, as its sensitivity and specificity are rather poor.