CT can reveal abnormal masses that may be cancerous tumors. CT scans show the size and shape of the tumor, its precise location in the body, and whether the tumor is solid or hollow. Sometimes, a CT scan can tell the difference between a noncancerous and cancerous tumor, although a biopsy or other test is needed to make the final diagnosis. In a biopsy, a small piece of tissue is removed to be examined in a laboratory. During a CT-guided biopsy, the physician will use the CT scan as a guide as he or she inserts the needle into the right location to remove a sample of the tumor.
In addition to detecting cancer, CT scans have many other uses. They can show abscesses and other infections, strokes, head injuries and bleeding inside the skull, as well as a variety of other medical conditions.
For obese patients, CT scanning may be a more useful diagnostic tool than ultrasound, because large amounts of body fat can interfere with ultrasound waves, producing poor images.