Tests That Help Evaluate Non-Hodgkin Lymphoma
Your doctor may request other tests to learn more about your specific type of lymphoma and to see how widespread the lymphoma is. Along with previous exams, biopsy, and blood tests, these can help your doctor know the stage and prognosis of your disease and decide about the most effective types of treatment for you. You may need one or more of these tests.
An X-ray of the chest uses radiation to produce a picture of the organs and glands inside your chest. It is often done to look for enlarged lymph nodes in your chest area. This test requires no preparation in advance, takes only a few minutes, and causes no pain.
Computed tomography (CT) scan
A CT scan is a more sensitive X-ray that produces cross-sectional pictures of your body. These pictures help your doctor see where the lymphoma is located and whether it has spread to other parts of your body. It is helpful for finding lymphoma in the chest, abdomen, pelvis, head, and neck.
To have the test, you lie still on a table as it gradually slides through the center of the CT scanner. The scanner directs a continuous beam of X-rays at your body.
A CT scan is painless. You may be asked to hold your breath one or more times during the scan. You may need to take a dyelike substance called contrast material before the scan. This substance helps soft tissues show up in the scan. You may be asked to drink it. Or you may get it by an intravenous (IV) injection. If you need a contrast medium, you will not be allowed to eat for one to three hours beforehand. Some people have a flushing reaction to the injection. Be sure to tell your doctor if you have a strong reaction, such as hives or trouble breathing, to the contrast material or if you have in the past. The contrast material will gradually pass through your system and exit through your bowel movements.
This test finds inflammation, which may show up in areas of infection or where tumors are growing in bones and other organs. It also helps your doctor know whether you have a slow- or fast-growing type of lymphoma. The first step is for a radiologist to inject a radioactive form of gallium into one of your veins. This substance is attracted to some types of lymphoma. Two to three days later, you’ll go in for scanning. A special camera detects the radioactivity, which shows the location of the gallium. Although the gallium scan will not detect most slow-growing lymphomas, it will recognize most fast-growing lymphomas. This test is not used much since PET scans became available, but it can still be useful in finding some lymphoma deposits that the PET scan may miss. It is useful for ruling out a diagnosis of infection. Your doctor may also use this scan to evaluate enlarged lymph nodes after treatment.
Lumbar puncture (spinal tap)
This procedure may help find out whether the disease has spread to the spinal cord or brain. A doctor inserts a thin, hollow needle between the bones in your lower spine or back to withdraw some cerebrospinal fluid (CSF). A doctor looks at the removed fluid under a microscope for lymphoma cells. This test is not usually needed in people with lymphoma unless they have certain types of lymphoma, or if they have symptoms that might be caused by the spread of lymphoma to the brain.
Magnetic resonance imaging (MRI)
MRIs use radio waves and magnets. The energy from the radio waves creates patterns formed by different types of tissue and diseases. This produces detailed cross-sectional pictures that look like slices of the body. This test is helpful in examining your brain and spinal cord. Or it may be used if the results of an X-ray or CT scan aren’t entirely clear.
For this test, you lie still on a table as it passes through a tubelike scanner. The scanner directs a continuous beam of radio waves at the area being examined. A computer uses data from the radio waves to create pictures of the inside of your body. You may need more than one set of images. Each one may take two to 15 minutes. This test may last an hour or more. You may want to ask for earplugs if they aren’t offered since there is a loud thumping noise during the scan. If you are claustrophobic, you may be given a sedative before having this test. Having the scan done in a newer, more open MRI machine may be another option.
Positron emission tomography (PET) scan
A PET scan can survey your entire body, so it is often more helpful than a series of several different X-rays. It can help your doctor know if lymph nodes contain lymphoma. Your doctor may also use it after treatment to help confirm whether enlarged lymph nodes still contain lymphoma or if the enlargement is due to scar tissue. For this test, you get injected with a small amount of radioactive glucose. Then, you lie still on a table that is pushed into the PET scanner, which rotates around you, taking pictures. Some people are sensitive to the radioactive glucose and may have nausea, headache, or vomiting. The PET scan shows which parts of your body are using the most glucose. Glucose use is a sign of active, quickly dividing cells, such as lymphoma.
The images from a PET scan are not finely detailed like a CT or MRI scan, but they can show areas of increased cellular activity anywhere in the body, even if they don't show up on other tests. Many medical centers now have machines that combine PET and CT scans (PET and CT scanners), which are able to compare the information from the PET scan with the detailed image of the CT scan.
Ultrasound produces a picture of internal organs or masses using sound waves and their echoes. A small microphone-like instrument, called a transducer, emits sound waves, which travel into the area of the body being studied. The echoes that bounce back are picked up and converted into an image on a computer screen. This procedure uses no radiation. To have an ultrasound exam, you simply lie on a table and a technician moves the transducer along your skin over part of your body. Your doctor may use an ultrasound to find masses in your abdomen. The ultrasound can also show kidneys that are swollen when urine outflow has become blocked by enlarged lymph nodes.