Lymphovenous Canada: Lymphatic Diagnostic Tools

Lymphedema can usually be diagnosed on the basis of history and physical examination alone. Laboratory tests can exclude the causes of extremity edema. If the diagnosis is still in doubt, or further evaluation is needed with respect to therapy, other investigations are available.

Computerized Tomography (CT scan) and Magnetic Resonance Imaging (MRI) are two diagnostic tools that can be used.

Lymphangiography (using injected blue dye) detected by x-rays used to be highly regarded, however because of the invasiveness of the test and potential complications, it is seldom used today. Complications of lymphangiography include damage of the remaining lymphatics, worsening of the existing lymphedema, infection, skin staining, allergic reaction and possible lung damage.

Lymphoscintography(LAS) has emerged as the current diagnostic study of choice for lymphedema. A very small amount of a radioactive material is injected into the patient into either the hand or the foot and images are obtained at regular intervals. This test can be undertaken in radiology departments or clinics.

One problem which has emerged with this test is that there are no agreed upon standards for administering LAS regarding the time period between injection to first image, second image and last image, account of activity , type and duration of activity, etc. Secondly, LAS provides a hazy picture which may give the impression that no lymphatic vessels exist. In some cases LAS tests indicate a false negative even though an individual may in fact have lymphedema. This may take place when there is a rapid absorption of injected contrast materials by highly active vessels, or when a Stemmer Sign is administered to test skin thickening in the toes and lymphedema does not exist in the foot. (For more information see the National Lymphedema Network's January-March 2006 issue of their publication Lymphlink with focuses on the benefits and challenges of imaging in the diagnosis of lymphedema.)

Lymphedema status can also be measured through such techniques as water displacement, sum of circuumferences, self-reporting, perometry, single frequency bioimpedance analysis (SFBIA) and bioimpedance spectroscopy (BIS) also known as bioelectrical impedance. Sum of circumference, water displacement, perometers, which measure limb size change, can however be effected by changes in diet and/or physical activity.

Recent technological enhancements to single frequency bioimpedance analysis (SFBIA) and bioimpedance spectroscopy (BIS) (which uses resistance to electrical current in comparing fluid compartments and body fat, have suggested that this technique may be a more effective way of measuring lymphedema in the future.

REFERENCES:

• A simple and innovative device to measure arm volume at home for patients with lymphedema after breast cancer. Journal of Clinical Oncology, 2006. Jean Lette, Department of Nuclear Medicine, Maisonneuve Hospital, Montréal, Québec www.jco.org/cgi/content/abstract/24/34/5434
• Lymphedema secondary to breast cancer: how choice of eamsure influences diagnosis, prevalence, and identifiable risk factors. Lymphology, 2008. S. Hayes, M. Janda, B. Cornish, D. Battistutta, B. Newman, Insitute of Health and Biomedical Innovation, School of Public Health andd School of Physical and Chemical Sciences, Queensland University of Technology, Australia.
• Reliability of bioimpedance spectroscopy and tonometry after breast conserving cancer treatment. Lymphatic Research and Biology, 2008. Moseley A, Piller N. Department of Surgery and Lymphedema Assessment Clinic, Flinders University and Medical Centre, South Australia, Australia.
• Single frequency versus bioimpedance spectroscopy for the assessment of lymphedema. Breast Cancer Research and Treatment, 2008. York SL, Ward LC, Czerniec S, Lee MJ, Refshauge KM, Kilbreath SL. Faculty of Health Sciences, University of Sydney, P.O. Box 170, East Street, 2141, Lidcombe, NSW, Australia.
• 13th International Conference on Electrical Bioimpedance and 8th Conference on Elecgtrical Impedance Tomography (Graz, Austria, August 29 to Sept. 2, 2007). Physiological Measurement, 2008. Richard H Bayford, Middlesex University UK, and Hermann Scharfetter, Graz Univsity of Technology, Austria.

Watch for it!
A new intravenous approach to imaging has just come onto the market using a contrast agent that is commonly used for magnetic resonance images (MRI's). This agent is put in the blood through a simple injection. By the next day the movement of this agent into the lymphatic system shows up on the imaging screen. (see Jack Hay's article which includes an explanation of the science of imaging).