Key Terms: Contrast medium, Lymph node, Lymphoma.
Definition
Lymphangiography is a type of diagnostic testing technique in which x rays (called lymph node angiograms) and the injection of a contrast medium (a substance that provides a contrast between the tissue or organ being filmed and the medium) are used to visualize lymphatic circulation and the lymph nodes.
Purpose
The lymphatic system consists of tissues, organs, and vessels that aid in circulating body fluids and defending the body from damage by foreign substances such as viruses, bacteria, or fungi. However, certain cancers may also spread through the lymphatic system. Thus, lymphangiography is sometimes used to:
- diagnose the presence or spread of tumors, lymphatic cancer (lymphoma), and other cancers
- distinguish primary lymphedema (when swelling in the lymphatic system arises from missing or impaired lymphatic vessels) from secondary lymphedema (swelling caused by damaged lymph vessels or lymph nodes that have been removed)
- localize tumors for surgical removal
- assess the effectiveness of chemotherapy and radiation therapy in treating problems associated with metastatic (spreading) cancer
Although the results of lymphangiography are considered reliable, additional tests, studies, and clinical observations are necessary to determine a precise diagnosis. By itself, lymphangiography misses cancer in about 20% of cases. One of the major drawbacks of lymphangiography is its failure to fill certain lymphatic channels and groups of lymph nodes—a failure that may be due to infection, injury, or tumor spread. When this filling failure occurs, certain segments of the lymphatic system in the abdomen and pelvis cannot be visualized; thus, metastatic disease can be neither confirmed nor ruled out.
Since the late 1990s, conventional lymphangiography (using an iodine oil-based contrast agent) has been used almost exclusively for the staging of urologic pelvic and testicular malignancies. The test may demonstrate metastases within lymph nodes of normal size that are missed on computed tomography (CT) imaging. Technical innovations in nuclear diagnostics and computer imaging largely replaced lymphangiography with simpler, safer, and more reliable techniques of visualizing the lymphatic system (such as lymphangioscintigraphy, or isotope lymphography).
Precautions
Because of the possibility of an adverse reaction to the contrast medium, lymphangiography is usually not administered to patients with lung problems, heart disease, or severe kidney or liver disease.
Individuals with allergies to shellfish, iodine, or dye used in other diagnostic tests may receive steroids or antihistamines before the test to decrease the risk of allergic reactions.
Description
Lymphangiography testing may be done on an inpatient or outpatient basis. A sedative may be given to help the patient relax. After the skin of each foot is cleaned with an antiseptic, a blue indicator dye (which does not show up on x rays) is injected between the first, second, and third toes of each foot. The dye spreads into the lymphatic system in about 15 to 30 minutes. The thin, bluish lines that appear on the top of each foot delineate the lymphatic vessels. Next, a local anesthetic is injected, and a small incision is made into one of the larger blue lines in each foot. A needle or catheter (a thin flexible tube) is inserted into a vessel in each foot, and an oilbased contrast medium (such as Ethiodol) is injected at a slow, steady rate. A feeling of pressure may occur as the contrast medium is injected, but the patient must lie still to avoid dislodging the needle.
A fluoroscope (a device consisting of a fluorescent screen on which the shadows of objects that come between the screen and an attached x-ray apparatus can be viewed) is used to monitor the progress of the contrast medium as it spreads slowly (taking about 60 to 90 minutes) through the lymphatic system, traveling up the legs, into the groin, and along the back of the abdominal cavity. After the contrast agent is injected, the catheter is removed and the incisions are stitched and bandaged. Then x rays are taken of the legs, pelvis, abdomen, and chest areas. The following day, an additional set of x rays is obtained.
After the test, the patient's skin, feces, and urine may have a bluish tint for two to three days (until the marker dye disappears), and there may be some discomfort behind the knees and in the groin area. Test results are reported to the doctor or patient from a few hours to a few days after the procedure.
Preparation
There is usually no special preparation needed before lymphangiography—such as restrictions in diet, activity, or medication intake. However, some facilities may require a clear liquid diet for a specified period of time before the test. In addition, for comfort reasons, patients may be asked to empty their bladders before testing. A patient undergoing lymphangiography (or a close family member) must sign a consent form before the test is administered.
Aftercare
After testing, the patient's blood pressure, pulse, breathing status, and temperature are monitored at regular intervals until they are stable. Any lung complications are noted, such as hoarseness or shortness of breath, chest pain, low blood pressure, low-grade fever, and blueness of lips and nailbeds due to clotting of the dye.
Bedrest for at least 24 hours following the test is recommended, with feet elevated to help reduce swelling at the incision sites. The incision sites may be sore for several days, and ice packs may be applied to these sites to further reduce swelling. The patient should also inspect the incision sites for infection. Sterile dressings should remain in place for two days, and the incision sites should be kept dry until after the sutures are removed (7 to 10 days after the test).
Risks
There is a risk of infection or bleeding caused by introducing the needle or tube through the skin or an allergic reaction—usually not serious—to the contrast medium. There is also a slight risk of oil embolism (obstruction of a blood vessel) due to the oil-based contrast medium. The contrast medium eventually seeps from the lymphatic channels into the general circulation, where it may travel to, and lodge in, the lungs.
There is some radiation exposure involved in the procedure. Although pregnant women and children are particularly sensitive to these risks, physicians may order the procedure when the benefits appear to outweigh the risks.
Normal Results
Normal test results indicate no anatomical or functional abnormalities.
Questions to Ask the Doctor
- What is the purpose of the test?
- How long will the test take?
- Will I be sedated or get anesthesia before the test?
- Is there anything special I need to do before the test?
- Can I drive myself home after testing?
- When will I get the results?
Abnormal Results
Abnormal results may indicate:
- filariasis (a tropical disease caused by worms living in the lymphatic system)
- Hodgkin's or non-Hodgkin's lymphoma (cancers of the lymphatic system)
- inflammation
- metastatic cancer
- primary lymphedema
- retroperitoneal tumors (tumors lying outside of the peritoneum—the membrane lining the abdominal cavity)
- trauma
Resources
Books
Fischbach, Frances Talaska. A Manual of Laboratory and Diagnostic Tests. 6th ed. Philadelphia: Lippincott Williams and Wilkins, 2000.
Periodicals
Bellin, Marie-France, Catherine Beigelman, and Sophie Precetti-Morel. "Iron Oxide-Enhanced MR Lymphography: Initial Experience." European Journal of Radiology June 2000: 257–264.
Winterer, Jan Thorsten, Ulrich Blum, Stephan Boos, Stavros Konstantinides, and Mathia Langer. "Cerebral and Renal Embolization After Lymphangiography in a Patient with Non-Hogkin's Lymphoma: Case Report." Radiology February 1999: 381–385.
Organizations
American College of Radiology. .
Lymphoma Research Foundation of America. .
—Genevieve Slomski, Ph.D.
