Esophageal function scintigraphy (synonyms: esophageal function scintigraphy (OFS); esophageal function scintigraphy (OFS); esophageal function scintigraphy; esophageal scintigraphy) is a diagnostic nuclear medicine procedure used as a noninvasive examination method to visualize a pathologic disorder of food transport through the esophagus. The procedure is of critical importance because of the possible assessment of individual passage sites.
Indications (areas of application)
- Dysphagia (dysphagia) – the use of esophageal function scintigraphy in the presence of dysphagia is useful because dysphagia can lead to a massive impairment of swallowing function due to even a minor change in the structures involved in the swallowing act. With the help of the scintigraphic imaging method, the localization of the disorder can be precisely revealed. In addition, esophageal function scintigraphy can achieve a quantitative assessment of swallowing function.
- Collagenoses – collagenosis is a disease of connective tissue that occurs as a result of an autoimmune reaction (immune reaction directed against the body). Collagenoses include systemic lupus erythematosus (SLE), polymyositis (PM) or dermatomyositis (DM), Sjögren’s syndrome (Sj), scleroderma (SSc) and Sharp’s syndrome (“mixed connective tissue disease”, MCTD). Collagenoses can also manifest in the swallowing and digestive tracts, so esophageal function scintigraphy can be used to detect co-disease of the esophagus.
- Neuromuscular system disease – neuromuscular function is critical to the control and therefore the progression of the swallowing act. Thus, if a nerve structure is impaired, the swallowing act may be impaired. Quantification of symptoms and localization of the altered structure can be achieved by esophageal function scintigraphy.
- Progress monitoring of therapeutic measures – to verify a therapeutic success, esophageal function scintigraphy can be used.
Contraindications
Relative contraindications
- Lactation phase (breastfeeding phase) – breastfeeding must be interrupted for 48 hours to prevent risk to the child.
- Repeat examination – no repeat scintigraphy should be performed within three months due to radiation exposure.
Absolute contraindications
- Gravidity (pregnancy)
Before the examination
- Abstention from food – the patient should not have eaten for three hours before the examination. However, ingestion of fluids is usually possible before the examination. If achalasia (dysfunction of smooth muscle in hollow organs, so that there may be a movement disorder of the esophagus) is suspected, the patient must fast for twelve hours before the examination.
- Radioactive marker placement – a radioactive marker substance is placed at the level of the cricoid cartilage to mark the upper edge of the esophagus. Subsequently, the radioactive radiation is detected with a gamma camera (detect with the help of detectors), so that the marker substance can be removed again.
- Ingestion of radioactive food – to assess esophageal function, the patient ingests food laced with radiopharmaceuticals. For example, 99mTc-sulfur colloid or 99mTc-tin colloid are used as radioactive substances. For the sensitivity (percentage of diseased patients in whom the disease is detected by the use of the procedure, i.e., a positive finding occurs) of esophageal function scintigraphy, it is crucial that the consistency and the amount of food ingested are reproducible.
The procedure
The basic principle of scintigraphic esophageal examination is based on the determination of radioactive-labeled food in the esophagus. Thus, a plot of the time course of radioactive distribution in the esophagus is used to evaluate the examination. By combining the measured values from the individual swallowing cycle passages, an overall evaluation can be created. The measured values are compared with physiological data to assess the presence of a disorder.Within twelve seconds after swallowing the food, 85% of the food and 91% of the absorbed liquid should have reached the stomach. If physiological measured values are determined during scintigraphy, an esophageal motility disorder (mobility disorder) can be excluded with a high degree of probability. As a consequence of the marked differences between the respective patients in the individual swallowing actions, up to ten individual swallowing actions must be evaluated per patient for reproducible results of esophageal function scintigraphy.
After the examination
- No special measures are necessary after scintigraphy. The procedure is usually performed on an outpatient basis.
Possible complications
- Intravenous application of radiopharmaceutical may result in local vascular and nerve lesions (injuries).
- Radiation exposure from the radionuclide used is rather low. Nevertheless, the theoretical risk of radiation-induced late malignancy (leukemia or carcinoma) is increased, so that a risk-benefit assessment should be performed.
- Allergy – allergic reactions to ingested food are possible. Based on this, a food allergy should be excluded in the medical history.