Lymph nodes play an important role in the immune system. They help store white blood cells that fight infection. They also trap cancer cells.
Lymph nodes are located throughout your body. A network of lymph vessels connects them. These vessels carry fluid containing white blood cells in and out of the lymph nodes. This fluid is called lymph.
Lymph nodes and lymph vessels do not normally show up on an X-ray. A special procedure called a lymphangiogram is needed to see them.
Doctors often use a lymphangiogram to see whether cancer has spread. In this case, you will probably also need a lymph node biopsy. Your doctor will remove either an entire lymph node or a small sample to check for cancer cells.
However, not all lymphangiograms are related to cancer. Your doctor may perform one to diagnose swelling in your arm or leg. The procedure may also be used to diagnose parasitic diseases, such as filariasis.
Tell your doctor if you are pregnant. The radiation from X-rays may be more problematic for pregnant woman. Also, tell your doctor if you have ever had:
- allergic reactions to substances containing iodine
- allergic reactions to X-ray dye (contrast material)
- bleeding problems
Your doctor may instruct you to fast for several hours before the test. Ask him or her for specific instructions.
You will sit down and the person performing the procedure will clean your feet. A blue dye called contrast will then be injected into the webbing between the first and second toes on each foot. This is not the actual test. It is just used to locate your lymph channels. After a few minutes, the dye will turn your lymph channels blue.
Your doctor will select one of the larger lymph channels and numb the area. A small cut will be made, and then a tube will be inserted into the channel. This will be repeated on the other foot. Once both tubes are in, more contrast dye will be slowly injected.
Unlike the lymphatic system itself, the dye is visible on X-ray images. Your doctor can use X-rays to follow the path of the dye throughout your lymphatic system. This can help detect blockages or swollen lymph nodes.
You may need to return the day after your procedure for more X-rays.
You will typically receive stitches to close the cuts on each foot. You can expect to feel some pain and soreness in the area.
Don’t be alarmed if your skin appears blue for a day or two after the procedure. This is normal. It’s also normal for your vision to turn blue for about two days. Your urine and stool will be discolored as well.
Abnormal results mean that a lymph vessel is blocked or a node is swollen. This could be caused by cancer, infection, injury, or previous lymphatic surgery.
Do not try to interpret your results on your own. Talk to your doctor. Abnormal results may have many causes and not all of them are frightening.
Any time you have an X-ray, you receive some low-level radiation exposure. However, these levels of radiation are not generally thought to be dangerous. Radiation may be more of an issue for children and pregnant women. However, the risk of damage to the fetus during an X-ray is low.
There are also risks associated with the dye used in the procedure. It can sometimes cause:
- allergic reaction
- lymph vessel inflammation