The lymphatic system is made up of lymph nodes and lymph vessels (lymphatics) that link the lymph nodes. The nodes harbor a type of white blood cell (lymphocytes) that helps fight infections.
When an infection is present, the lymph nodes swell, help proliferate the white blood cells, and try to trap the organisms that are causing the infection. The lymph nodes also function to filter and trap cancer cells.
The lymph nodes and vessels are not normally seen on an X-ray, so a contrast material and/or radioisotope (radioactive compound) is injected into the system to visualize it.
How the test is performed
The test is performed in a hospital radiology department or in the health care provider’s office by an X-ray technician.
If leg or arm swelling is being evaluated, you may be offered a sedative to help relax. You will be put in a specially constructed chair or on the X-ray table. The skin of each foot is cleansed, and a small amount of blue dye is injected between the toes into the webbing.
Within 15 minutes, thin, bluish lines appear on the top of the foot. This identifies the lymphatics. Then, a local anesthetic is given and a small incision is made into one of the larger blue lines. A needle or catheter (a thin flexible tube) is inserted into a lymphatic channel in each foot, and a contrast medium is injected into each foot at a very slow rate (60 to 90 minutes for all the contrast medium to be injected).
A fluoroscope (a special X-ray machine that projects the images on a TV monitor) is used to follow the dye as it spreads through the lymphatic system up the legs, into the groin, and along the back of the abdominal cavity.
Once the contrast medium is injected, the catheter is removed, and the incisions are stitched and bandaged. X-rays are taken of the legs, pelvis, abdomen, and chest areas. The next day, another set of X-rays may be taken.
If a site of cancer (breast or melanoma) is being studied to evaluate spreading, a mixture of blue dye and a radioactive tracer is injected next to the mass. Special cameras detect the spread of tracer along lymph channels to outlying nodes.
A surgeon will then use the visible blue dye or radioactivity within nodes to guide biopsy within adjacent tissues (such as the arm pit for breast cancer) to determine possible routes of cancer spread.
How to prepare for the test
Inform the health care provider if you are pregnant or you have bleeding problems. Also mention if you’ve had allergic reactions to X-ray contrast material or any iodine-containing substance. You must sign a consent form. You may be asked to restrict your diet to clear liquids for a period of time before the test. You may wish to empty your bladder just before the test.
If you are undergoing lymphangiography for sentinel lymph node biopsy (in breast cancer and melanoma), you will need to prepare for the operating room. A surgeon and anesthesiologist will discuss how to prepare for the procedure.
For infants and children:
The preparation you can provide for this procedure depends on your child’s age and experience. For specific information regarding how you can prepare your child, see the following topics:
- infant test or procedure preparation (birth to 1 year)
- toddler test or procedure preparation (1 to 3 years)
- preschooler test or procedure preparation (3 to 6 years)
- schoolage test or procedure preparation (6 to 12 years)
- adolescent test or procedure preparation (12 to 18 years)
How the test will feel
There will be a brief sting from the needle and blue dye injected between the toes. There is another brief sting with the injection of the local anesthetic. There may be a feeling of pressure as the contrast medium is injected, and there may be some discomfort behind the knees and in the groin area.
The incisions will be sore for a few days. The blue dye will color the urine and stool for about 48 hours. The skin and possibly the vision will take on a bluish cast temporarily.
Why the test is performed
The test, in conjunction with senitel lymph node biopsy, is used to evaluate the possible spread of cancers and the effectiveness of cancer therapy. The use of contrast and X-rays is used to help determine the cause of swelling in an arm or leg and check for parasitic (organisms that live on another) diseases.
What abnormal results mean
Enlarged nodes (swollen glands) that have a foamy appearance may indicate a lymphatic cancer. Nodes or parts of the nodes that do not fill with the contrast material may indicate a cancer spreading throughout the system. Blockage of the lymph vessels may be caused by tumor, infection, trauma, or prior surgical disruption of the lymph pathways.
Lymphangiograms, in conjunction with senitel node biopsy, simply identify the draining pathways near a mass, and thus, the spread of cancer can only be determined after biopsy of visualized nodes.
Additional conditions under which the test may be performed:
- Hodgkin’s lymphoma
- non-Hodgkin’s lymphoma
What the risks are
There is a possibility of an reaction to the contrast medium. An infection is possible at the site of the injection. The dye or contrast material may cause a fever and inflammation of the lymph vessels.
There is low radiation exposure. However, most experts feel that the risk of most X-rays is smaller than other risks we take every day. Pregnant women and children are more sensitive to the risks of the X-ray.
The contrast medium can stay in the nodes for up to 2 years.
by Sharon M. Smith, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.