MRIs use radio waves to show pictures of the soft tissue sarcoma, explains American Cancer Society. The radio waves release energy in the body in a pattern depending on the shape of the tissue and the disease present. Computers turn the pattern into a comprehensive image of the sarcoma.
MRIs show a variety of information about the tumor, including the location of the tumor in the body, the size of the tumor, and the type of tissue the tumor originates from, states American Cancer Society. This information helps the doctor plan the biopsy of the tumor. MRIs are most beneficial in diagnosing soft tissue sarcoma in the brain, spinal cord, arms and legs.
However, an MRI is not the only way that soft tissue sarcoma can be identified, notes American Cancer Society. An X-ray is often used first when a lump is found. A CT scan, unlike a regular X-ray, takes pictures of the area as it rotates around the body. This type of test is beneficial if the lump is in the chest or stomach, or to see if the sarcoma spread to the liver, lungs or other organs. An ultrasound uses sound waves instead of radiation to transmit pictures of the sarcoma. However, if a CT scan or MRI is used, an ultrasound is often not needed.