Lymphoscintigraphy: defining a clinical role.

Radionuclide lymphoscintigraphy is a useful technique for differentiating lymphedema from other causes of swelling, and may sometimes be useful for delineating collateral lymphatics, the level of obstruction, and the presence of lymphoceles or abnormal collections of lymphatic vessels, if they communicate sufficiently with normal lymphatic vessels. Standardization of technique is important to provide better intrapatient and even interpatient comparison. Symmetry, numbers, and locations of lymphatic vessels, lymph nodes, abnormal collections, and dermal collaterals are helpful in the qualitative assessment of lymphoscintigraphy. In addition, region-of-interest analysis may be used to quantitate the clearance of the radiopharmaceutical from the injection site and its accumulation in draining lymph nodes. The constellation of findings may be used to assess the severity of the lymphatic obstruction, the involvement of clinically normal limbs, and to plan therapy.