If you or your doctor suspects you might have kidney cancer, a complete medical history will be taken by your physician and a physical examination will be conducted. If results from these tests indicate the potential presence of kidney cancer, additional tests will likely be done to determine the cancer's location, extent, stage and other important information. The following imaging procedures are frequently used in the diagnosis of kidney cancer:
Ultrasound/Ultrasonography: This technology uses sound waves to create images of internal organs. This test is painless and does not expose the patient to radiation. Ultrasound can be helpful in determining whether a mass found on the kidney mass is solid or fluid-filled. Ultrasound images of most kidney tumors look different from those of normal kidney tissue. These differing images can also help differentiate between some types of benign and malignant kidney tumors.
CT Scan: Computed tomography (also known as a CT or CAT Scan) is a very detailed x-ray that produces multiple, cross-sectional images of the body. While the process of a CT scan takes longer than a regular x-ray, it is among the more useful tests for discovering and viewing a tumor inside the kidney. CT scans provide precise information about the size, shape and position of a tumor and can also aid in locating surrounding lymph nodes that might also contain cancer.
MRI: Magnetic Resonance Imaging (also called an MRI), like CT scans, provides detailed images of internal organs and the body's soft tissues. In many cases, MRI can be helpful in determining the nature of a kidney tumor. When the tumor is not well characterized with a CT Scan, an MRI may provide further information. An MRI exam takes longer to perform than a CT Scan. It is usually done with a patient placed closed casket style compartment, whereas the CT is performed in an open space. However, MRI does not expose the patient to any radiation, whereas CT Scan images are obtained by radiating the patient. MRI scans are often done when there is suspicion that the kidney cancer has grown into major blood vessels. If symptoms suggest it, MRI's are also used to view the possible spread of cancer to the brain.
PET Scan: Positron Emission Tomography (also referred to as a PET scan) is a highly-specialized diagnostic imaging study that provides information about how extensively a cancer may have spread. Currently PET Scan is the most accurate way of determining if there has been spread of cancer in the body. PET Scan relies on the concept that cancer cells are growing and dividing rapidly. Since the cancer cells grow fast, their rate of metabolism of sugar molecule is faster than normal non-cancerous cells. PET Scan essentially detects the cells that are rapidly metabolizing sugar molecules. Areas in the body with faster sugar metabolism indicate areas where cancer cells are growing. Different than a CT scan and MRI, PET scans produce images of the body using information about a cell's metabolism. CT and MRI can detect tumor cells that are greater than about ½ inch in size. PET Scan can detect location of much smaller cancer cells. Furthermore, if a possible abnormality is seen on MRI or CT, but the doctor is not sure that the abnormality is a cancerous tumor, PET Scan may be able to diagnose the area of abnormality as a malignant tumor or not. With such detailed imaging, PET scans help physicians differentiate malignant tumors from benign and provides them a precise tool for determining a cancer's stage. For this reason, PET scans are often used in combination with MRI or CT examination.