Radionuclide Gastroesophageal Motor Studies

Disorders of the upper digestive tract have a high impact on modern society, in terms of both direct and indirect health care costs and of social burden. The most common presenting symptom is either dysphagia or dyspepsia. Discriminating specific diagnoses within this wide group of diseases requires sound clinical judgment and application of procedures to distinguish organic from nonorganic disease and to further characterize the functional or motility disturbance of nonorganic diseases. Non-radionuclide-based diagnostic techniques include both noninvasive tests (upper gastrointestinal barium series, ultrasonography, and breath test for gastric emptying) and invasive procedures (fiberoptic endoscopy, esophagogastroduodenoscopy, pharyngeal manometry, stationary esophageal manometry, 24-h pH monitoring, esophageal biliary reflux monitoring, multichannel intraluminal impedance, and electrogastrography). Some of these techniques are not well tolerated by patients or not widely available. Radionuclide transit/emptying scintigraphy provides a means of characterizing exquisite functional abnormalities with a set of low-cost procedures that are easy to perform and widely available, entail a low radiation burden, closely reflect the physiology of the tract under evaluation, are well tolerated and require minimum cooperation by patients, and provide quantitative data for better intersubject comparison and for monitoring response to therapy. Despite the relatively low degree of standardization both in the scintigraphic technique per se and in image processing, these methods have shown excellent diagnostic performance in several function or motility disorders of the upper digestive tract. Dynamic scintigraphy with a radioactive liquid or semisolid bolus provides important information on both the oropharyngeal and the esophageal phases of swallowing, thus representing a useful complement or even a valid alternative to conventional invasive tests (such as stationary esophageal manometry) for evaluating abnormalities of oropharyngoesophageal transit. Clinical applications of esophageal transit scintigraphy include disorders such as nutcracker esophagus, esophageal spasm, noncardiac chest pain of presumed esophageal origin, achalasia, esophageal involvement of scleroderma, and gastroesophageal reflux and monitoring of response to therapy (either medical or surgical treatment of disease-for example, organic disease such as esophageal cancer). Scintigraphy with a radiolabeled test meal represents the gold standard for evaluating gastric emptying, whereas more recent radionuclide methods include dynamic antral scintigraphy and gastric SPECT for assessing gastric accommodation. Clinical applications of gastric-emptying scintigraphy include, among others, evaluation of patients with dyspepsia and evaluation of gastric function in various systemic diseases affecting gastric emptying. The present review includes the proposal of clinical algorithms for evaluating patients with the main disorders of the upper digestive tract. These algorithms, originally derived from available literature, have been developed on the basis of a vast clinical experience in conjunction with the specialists more deeply involved in the care of patients with such disorders (medical and surgical gastroenterologists and nuclear medicine physicians). The role of radionuclide gastroesophageal motor studies is clearly identified in the various steps of patients' management, from the initial diagnostic approach to functional characterization to postoperative follow-up or monitoring of medical therapy.