Barium Swallow X-ray
A barium swallow x-ray is used to study your upper gastrointestinal (GI) tract, specifically your esophagus and the back of your mouth and throat. For the test, you will swallow liquid containing barium that will coat your upper GI tract and make it easier to see the lining, size, and shape of these body parts on an x-ray. After you drink the liquid, you will lie on an exam table while an x-ray machine takes pictures. The exam usually takes about 20 minutes.

Chest X-ray
Chest x-rays are one of the most commonly performed diagnostic medical tests. This test provides a black-and-white image of your lungs, heart, and chest wall. The test is noninvasive, painless, and takes just a few minutes. You will stand in front of the x-ray machine and hold very still while an image is taken. X-rays, which are a form of radiation like light or radio waves, pass through your body and are absorbed in varying degrees. Your bones absorb more of the x-rays and appear white on the image. Muscle, fat, and organs (such as heart or lung tissue) absorb less radiation and will be dark on the image.

Computed Tomography (CT) Scan
Similar to x-rays, CT uses radiation to produce images of the inside of your body. Your internal organs, bones, soft tissue, and other body parts will show up light or dark on a computer screen depending on how much radiation is absorbed. While an x-ray is a two-dimensional picture, a CT scan can be a three-dimensional image that is much more detailed than an x-ray. For the test, you will lie on a table that will slide into the CT scanner, and the x-ray beam will rotate around your body. Depending on the reason for this test, you may be given a dye (contrast agent) to help areas of your body show up better on the image. The actual CT scanning takes less than 30 seconds, and the entire process is usually completed within 30 minutes.

Esophageal pH Monitoring
Esophageal pH monitoring measures how often, and for how long, stomach acid enters your esophagus. A tube is used to insert a small probe through your nostril and into the lower part of your esophagus. The probe is attached to a small monitor that you will wear on your belt or over your shoulder (some new devices operate wirelessly). The monitor records acid reflux activity for 24 hours.

Magnetic Resonance Imaging (MRI)
MRI uses a magnetic field, radio waves, and a computer to produce detailed images of the inside of your body. For the test, you will lie on a table that slides into a cylinder-shaped tube. Similar to computed tomography, you may be given a dye (contrast agent) for the test. MRIs are typically better than x-rays, computed tomography scans, and ultrasounds at displaying diseased tissue. The entire exam usually takes about 1 hour, but occasionally may take longer.

Positron Emission Tomography (PET) Scan
For a PET scan, you will be given a radioactive drug (radiotracer) that will collect in areas of your body that have high levels of chemical activity, such as disease areas. Unlike computed tomography (CT) scans and magnetic resonance imaging, which show important anatomic information, a PET scan measures important body functions, such as blood flow, oxygen use, and sugar metabolism. For a PET scan, you’ll lie on a table that will slide into a cylinder-shaped tube. The tracer will show up as bright spots on the computer screen as special cameras record energy emission from the radiotracer in your body. Typically, it takes about 50 minutes for the radiotracer to travel through your body and another 30 minutes for the PET scan. Sometimes, a PET scan is combined with a CT scan using one process.

Pulse Oximetry
During pulse oximetry, a small device is painlessly clipped onto part of your body (often your fingertip or ear lobe) and measures the oxygen level in your blood. The pulse oximeter may be left on briefly for a single reading, or you may need to wear it for a longer period of time.

Upper Endoscopy
An upper endoscopy allows your doctor to directly examine your upper gastrointestinal (GI) tract. An endoscope—a long, flexible tube with a camera—will be inserted into your mouth, through your esophagus, and into your stomach. The camera transmits images of the inside of your GI tract to a television screen, giving your doctor a more detailed and accurate image than an x-ray. The process can take up to 20 minutes. In addition to diagnosing disease, an upper endoscopy can be used to treat certain conditions (for example, stretching narrowed sections of your esophagus or removing abnormal tissue growth in your stomach).