Ewing Sarcoma: Tests After Diagnosis

A CT scan is also called a CAT scan. It uses X-rays to make detailed 3-D pictures of the inside of your body. After diagnosing Ewing sarcoma, a CT scan may be done on your chest or belly (abdomen). A CT scan of your chest is commonly done to see if the cancer has spread to your lungs.

To have the test, you lie still on a narrow table as it slowly slides through the center of the ring-shaped CT scanner. Many X-rays are taken as the table slides through. A computer uses the X-rays to make detailed pictures. A CT scan doesn't hurt. You may be asked to briefly hold your breath a few times during the scans. A contrast medium might be put into your blood through a vein in your hand or arm before or during the scan. This helps tumor details show up better on the scans.

An MRI uses magnets, radio waves, and a computer to make detailed pictures of the inside of your body. An MRI may be used to find out the exact size and extent of the spread of the main tumor. It's also very useful for looking at nerves and blood vessels near the tumor. MRI can be used to look for areas of cancer spread in other parts of your body, too. In some cases, you’ll get a contrast dye injected into your blood before getting the scan. 

MRIs don’t hurt. But they can take a long time to do (up to an hour or so). During that time, you’ll need to lie still on a narrow table that moves into a long, narrow tube. If you have a fear of enclosed spaces or are a young child, your healthcare provider may give a sedative to help you stay calm during the test. Newer, more open MRI machines can sometimes be used instead. But the images are not as clear. You might be given earplugs because there are loud banging and whirring noises during the test.

A bone scan looks at your whole skeleton. It's used to look for the spread of bone tumors anywhere in your body. For this test, a small amount of a mildly radioactive substance put into your blood through a vein in your arm or hand. The substance travels through your bloodstream and collects where there's abnormal bone growth. A machine then scans your body and makes images of the places where the radioactivity has collected. These may be areas where the cancer has spread to your bones.

More detailed tests are then needed to get a close look at these areas. Many times, a PET scan is used instead of a bone scan.

A PET scan looks at your entire body.

For this test, a mildly radioactive sugar is injected into a vein. Cancer cells absorb more of this sugar than normal cells, and the radioactive material shows up as "hot" spots on the images taken during the scan. To have the scan, you’ll need to lie still on a table that’s pushed into the PET scanner. The whole process may take several hours. A PET scan is often combined with a CT scan (PET-CT scan). This allows areas that show up on the PET scan to be compared to the more detailed images of the CT scan. This test is very good for looking for cancer that has spread from where it first started.

These tests are done at the same time and may be needed after Ewing sarcoma has been diagnosed. They can help show if the cancer has spread to the bone marrow. This is the soft, spongy, inner part of many bones. For these tests, your healthcare provider uses hollow needles to take out tiny pieces (samples) of bone marrow and bone. The samples are often taken from the back of your hip bones.

Teens and adults may be awake when this is done (with the area numbed). But children are often given medicines to make them sleep during the test.

The bone and bone marrow samples are sent to a lab where tests are done to check for cancer cells.