Computed Tomographic scan (CT scan) is an x-ray procedure that gives cross-sectional images of the body. The CT scan may help detect lymph nodes in the pelvis that are enlarged because of cancer. Generally, a CT scan is done only if the cancer is high risk (high PSA, high Gleason score, or abnormal findings on DRE).
Magnetic Resonance Imaging
Magnetic Resonance Imaging (MRI) is similar to a CT scan except that it uses magnetic fields instead of x-rays to create internal pictures of your body. MRI is better than CT at imaging the prostate, but has limited usefulness for distinguishing benign from cancerous areas. Standard MRI, therefore, has limited usefulness for determining the extent of disease. Research is being carried out to determine whether MRI techniques can “see” cancer better. Currently, there is no established role for MRI in prostate cancer.
A test called a Bone Scan is performed to see if the cancer cells have spread to the skeleton. For this test, a radiology technician injects a small amount of radioactive material into the patient's bloodstream and the patient returns 3 hours later for the scan. The radioactive material collects in the area where there are bone-activating cells. A scanner then pinpoints the areas where the radioactive material collects, so these areas can be evaluated for possible sites of bone metastasis. This study is limited to those with high-risk disease (high PSA, high Gleason score, or abnormal findings on DRE).
Lymph Node Dissection
The lymph nodes are often the first location where prostate cancer spreads. The physician can usually estimate the likelihood that cancer has spread to the lymph nodes based on the rectal examination, PSA, and biopsy results; and by using a published nomogram. If there is a high likelihood that the cancer has spread to the lymph nodes, the physician may elect to surgically sample, remove and examine the lymph nodes under a microscope. This is often done at the time of radical prostatectomy in intermediate and high-risk cases. Special imaging techniques are being developed to study lymph nodes without having to surgically remove them.