A lymphangiogram is a special x-ray of the lymph nodes and lymph vessels. Lymph nodes produce white blood cells (lymphocytes) that help fight infections. The lymph nodes also filter and trap cancer cells.
The lymph nodes and vessels are not seen on a normal x-ray, so a dye or radioisotope (radioactive compound) is injected into the body to highlight the area being studied.
How the Test is Performed
You may be offered medicine to help you relax before the test.
You sit in a special chair or on an x-ray table. The health care provider cleans your feet, and then injects a small amount of blue dye into the area (called webbing) between your toes.
Thin, bluish lines appear on the top of the foot within 15 minutes. These lines identify the lymph channels. The provider numbs the area, makes a small surgical cut near one of the larger blue lines, and inserts a thin flexible tube into a lymph channel. This is done on each foot. Dye (contrast medium) flows through the tube very slowly, over a period of 60 to 90 minutes.
Another method may also be used. Instead of injecting blue dye between your toes, your provider may numb the skin over your groin and then insert a thin needle under ultrasound guidance into a lymph node in your groin. Contrast will be injected through the needle and into the lymph node using a type of pump called an insufflator.
A type of x-ray machine, called a fluoroscope, projects the images on a TV monitor. The provider uses the images to follow the dye as it spreads through the lymphatic system up your legs, groin, and along the back of the abdominal cavity.
Once the dye is completely injected, the catheter is removed and stitches are used to close the surgical cut. The area is bandaged. X-rays are taken of the legs, pelvis, abdomen, and chest areas. More x-rays may be taken the next day.
If the test is being done to see if breast cancer or melanoma has spread, the blue dye is mixed with a radioactive compound. Images are taken to watch how the substance spreads to other lymph nodes. This can help your provider better understand where the cancer has spread when a biopsy is being performed.
How to Prepare for the Test
You must sign a consent form. You may be asked to not eat or drink for several hours before the test. You may wish to empty your bladder just before the test.
Tell the provider if you are pregnant or you have bleeding problems. Also mention if you have had an allergic reaction to x-ray contrast material or any iodine-containing substance.
If you are having this test done with sentinel lymph node biopsy (for breast cancer and melanoma), then you will need to prepare for the operating room. A surgeon and anesthesiologist will tell you how to prepare for the procedure.
How the Test will Feel
Some people feel a brief sting when the blue dye and numbing medicines are injected. You may feel pressure as the dye starts to flow into your body, particularly behind the knees and in the groin area.
The surgical cuts will be sore for a few days. The blue dye causes skin, urine, and stool discoloration for about 2 days.
Why the Test is Performed
A lymphangiogram is used with lymph node biopsy to determine the possible spread of cancer and the effectiveness of cancer therapy.
Contrast dye and x-rays are used to help determine the cause of swelling in an arm or leg and check for diseases that may be caused by parasites.
Additional conditions under which the test may be performed:
What Abnormal Results Mean
Enlarged lymph nodes (swollen glands) that have a foamy appearance may be a sign of lymphatic cancer.
Nodes or parts of the nodes that do not fill with the dye suggest a blockage and may be a sign of cancer spreading through the lymph system. Blockage of the lymph vessels may be caused by tumor, infection, injury, or previous surgery.
Talk to your provider about the meaning of your specific test results.
Risks related to the injection of the dye (contrast medium) may include:
- Allergic reaction
- 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 dye (contrast medium) can stay in the lymph nodes for up to 2 years.
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Witte MH, Bernas MJ. Lymphatic pathophysiology. In: Sidawy AN, Perler BA, eds. Rutherford's Vascular Surgery and Endovascular Therapy. 9th ed. Philadelphia, PA: Elsevier; 2019:chap 10.