Positron emission tomography
Diagnosis of soft-tissue sarcomas also begins with a thorough history and physical examination. Imaging studies can include either CT or MRI, although CT tends to be preferred for soft tissue sarcomas located in the thorax, abdomen, or retroperitoneum. Positron emission tomography (PET) also may be useful in diagnosis, although its most common use is for staging (see below). As with bone sarcomas, definitive diagnosis requires biopsy of the tumor with evaluation of histology by a trained pathologist.