The CT scan uses x-rays to produce detailed cross-sectional images of your body. CT scans are not usually used to diagnose esophageal cancer, but they can help show where it is in the esophagus and if it has spread to nearby organs and lymph nodes (bean-sized collections of immune cells to which cancers often spread first) or to distant parts of the body. The CT scan can help to determine whether surgery is a good treatment option.
A CT scanner has been described as a large donut, with a narrow table that slides in and out of the middle opening. You will need to lie still on the table while the scan is being done. CT scans take longer than regular x-rays, and you might feel a bit confined by the ring while the pictures are being taken. Instead of taking one picture, like a standard x-ray, a CT scanner takes many pictures as it rotates around you. A computer then combines these pictures into an image of a slice of your body.
Before the test, you may be asked to drink 1 to 2 pints of a liquid called oral contrast. This helps outline the esophagus and intestines so that certain areas are not mistaken for tumors. If you are having any trouble swallowing, you need to tell your doctor before the scan. You might also receive an IV (intravenous) line through which a different kind of contrast dye (IV contrast) is injected. This helps better outline structures in your body.
The injection can cause some flushing (redness and warm feeling, especially in the face). Some people are allergic to the dye and get hives. Rarely, more serious reactions like trouble breathing and low blood pressure can occur. Be sure to tell your doctor if you have any allergies or have ever had a reaction to any contrast material used for x-rays. You can be given medicine to help prevent and treat allergic reactions.
CT-guided needle biopsy: CT scans can also be used to guide a biopsy needle precisely into a suspected area of cancer spread. For this procedure, you remain on the CT scanning table while the doctor advances a biopsy needle through the skin and toward the tumor. CT scans are repeated until the needle is within the mass. A needle biopsy sample is then removed to be looked at under a microscope.