• Other vascular imaging • Blood tests for other conditions that can look like lymphedema History and Physical Examination A history and physical examination by a health-care provider who has experience with diagnosis and treatment of lymphedema is important for all patients with chronic swelling.193,194,198 Primary and Secondary lymphedemas have characteristic features that can be seen over time. The history should include age of onset, location(s) of swelling, pain and other symptoms, medications that can cause swelling, the course of progression of the swelling, and factors associated with swelling onset such as cancer, injury, or infection. A family history is important to the diagnosis of inherited forms of lymphedema. The physical examination includes an assessment of the vascular system (lymphatics, veins and arteries), skin and soft tissues in the swollen body part(s), palpation of lymph nodes, and looking for changes in body systems associated with various forms of inherited lymphedemas.181,182,202 Diagnostic tests and imaging must be paired with the information from the history and physical examination to make a correct diagnosis. For trunk, breast, genital, head and neck lymphedema, the history and physical examination is the currently accepted method of diagnosis.76,78 Soft Tissue Imaging Magnetic resonance imaging (MRI), computed tomography (CT) and some types of ultrasound (US) are able to detect the presence of extra fluid in the tissues.159,160,170 Fluid that is outside of cells (extracellular) and also outside of vessels (extravascular) is called tissue fluid or interstitial fluid. Lymphedema is one type of interstitial fluid build up that occurs when fluid is not being removed effectively by the lymph vessels. MRI, CT and US can show the presence of increased interstitial fluid but cannot tell the cause. These imaging techniques have to be put together with history, physical examination and sometimes other imaging tests.194 Other conditions such as heart failure or low proteins in the blood from liver disease or malnutrition can cause fluid to build up in the tissues. MRI, US and CT scans may be required to determine the cause of lymphedema, especially if there is a concern that the lymphedema might be the result of an untreated cancer. Lymph Vessel Imaging Lymphoscintigraphy is a nuclear medicine study used for imaging lymph vessels and lymph nodes.195 Radio-labeled particles of protein are injected just under the skin of the area of the body to be imaged. Usually technetium labeled sulphur colloid is used. Lymphoscintigraphy is accurate for detecting abnormalities of the lymphatic system in the extremities regardless of the cause.163,165,189 It demonstrates slow or absent lymph flow and areas of reflux (backflow). Lymphoscintigraphy can reveal abnormalities of lymph uptake in lymph nodes with some forms of lymphedema.168 Lymphoscintigraphy can predict response to treatment.167 Lymphoscintigraphy shows the main, larger lymph vessels and nodes. It shows the basic architecture of the peripheral lymphatic system. It does not show the deep transport lymph vessels carrying lymph from the nodes back to the blood circulation. Lymphoscintigraphy identifies lymphatic abnormalities at a late stage, after lymphedema has occurred. The type of lymphoscintigraphy done for the diagnosis of lymphedema is not available at all radiology departments. Most radiology departments, however, can do a form of lymphoscintigraphy used to identify the sentinel lymph node for cancers such as breast and melanoma. These studies for the sentinel lymph node are different from the lymphoscintigraphy studies done for diagnosis of lymphedema. Before undergoing a lymphoscintigraphy study the patient should inquire if the radiologist performing and reading the study has a large amount of experience with lymphoscintigraphy studies for the diagnosis of lymphedema. Lymphoscintigraphy, in combination with other vascular studies, can differentiate venous edema from lymphedema.190,196 Lymphoscintigraphy may not be necessary in some forms of secondary lymphedema where the diagnosis is clear from the history and physical examination or other imaging. In order to diagnose primary lymphedema, however, a lymphoscintigraphy must be done. Especially in children, a detailed study must be done that includes all potential areas of involvement and the contralateral normal limb or body part for comparison.166,169 These studies must be done by a radiologist familiar with primary lymphedema
Posted on: Tue, 23 Jul 2013 14:13:05 +0000
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