Q: I have been hearing a lot lately about imaging of my lymphatic system, is it a necessary thing to do?
A: This is an excellent question and it goes right to the heart of the matter. Another way to think about this question is what will be the significance of the imaging? Every patient is different and that includes their lymphedema. By using imaging techniques (primarily lymphangioscintigraphy or LAS), we can obtain a structural and functional picture of the invisible lymphatic system. This can include: showing how the system is working by following the tracer as it moves up the limb into the central circulation; identifying the places where it may be slowed or stop; and determining the extent of the blockage and diffusion of the tracer from the vessels. These are all useful pieces of information for the clinician to see and share with the patient. Sometimes in patients who have complications with other pathologic conditions (for example venous disease or lipedema in the legs) or those who have more involved problems in their lymphatic system (for example leakage of lymphatic fluid into the genitalia, abdomen, chest, or backward flow), imaging of the lymphatic system is needed to help in the diagnosis, develop appropriate treatment plans, and offer a better prognosis. In our clinic, we believe strongly in imaging and we strive to image all patients to examine the function of their lymphatic system. The patients appreciate seeing what to them and their doctors, has been invisible.
Q: I see that there are different techniques for LAS and I wonder if there is any standardization to imaging and if not, what does this mean? Is there any danger in the procedure?
A: These questions come up even at medical meetings concerning the lymphatic system. It is hard to give a straight definitive answer, but most of the experts don't worry about this too much. In the US, we give the single, small injection (like a TB test) in the skin of the hand or foot (intradermal), while in Europe it is predominantly given under the skin (subcutaneously). There is a difference between the two methods in that intradermal injections allow the tracer to move up the limbs faster compared to the subcutaneous injection. Therefore in the US, we image at earlier times than in Europe. Even though there is a difference in technique, both techniques give good images of the lymphatic system and that is why the experts don't really worry about the differences. Some people worry about possible dangers in the procedure. The first thing to wonder about is the radiation. The total dose of radioactivity is 1/20th of that found in a routine chest X-ray. This is not zero, but the dose is very low. The second point concerns the use of a needle stick into a limb with lymphedema. This is a common precaution on many do's and don'ts lists for lymphedema. In our clinic with over 1,000 patient images, we have not had one infection from the procedure. One must realize that this procedure uses a sterile needle and the skin is cleaned with an alcohol pad prior to injection. These two things greatly reduce the chance for infection.
Q: Some people have told me that their image was "normal" when they know they have lymphedema. Why is this?
A: This is a question that we sometimes encounter and the answer is not always clear because there are many possibilities. The first is that there really are no abnormalities in the function of the lymphatic system. Sometimes this is hard for a patient to understand since they have been told for some time that they have lymphedema; but having a clear diagnosis is important and not having lymphedema also can be liberating. As with many procedures, there is a degree of skill involved from the nuclear medicine technician and sometimes technical difficulties by the technician or even in the tracer preparation can lead to a poor image. It is also up to the experience and skill of the nuclear medicine radiologist and clinician and who determine the timing and sequence of images and then interpret the images. Even among experts, interpretations may differ.
Q: How much does a lymphangioscintigram cost and is it covered by insurance?
A: This is probably the second most asked question that we receive. For patients with Medicare, a properly justified physician request should be sufficient. In our facility (and many in the US), most insurance companies will cover the cost of lymphatic imaging for lymphatic disease. Sometimes this does require a letter of medical necessity from the physician. Occasionally a patient from out-of-network has trouble obtaining insurance coverage for the procedure (many are covered) and the hospital can work out a payment plan if they are paying out-of-pocket. Depending on individual facilities, the original billed charges (undiscounted) are probably in the range of $750-1,200. There is sometimes an additional charge of $100-300 for the reading by the nuclear medicine physician.
Michael Bernas, MS
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