LYMPHSCINTIGRAPHY IN PERIPHERAL LYMPHEDEMA USING TECHNETIUM-LABELLED HUMAN SERUM ALBUMIN: NORMAL AND ABNORMAL PATTERNS

K Nawaz, M Hamad, S Sadek, M Awdeh, E Higazi, B Eklof, HM Abdel-Dayem

Abstract


Lymphscintigraphy using Tc-99m human serum albumin (HSA) was examined in 23 patients with peripheral leg lymphedema. Each was injected intradermally with one mCi in the medial web space bilaterally. Images of the lower pelvis and both thighs were obtained within five minutes after injection using an extralarge
field view camera GE 500A with low energy all purpose collimator interfaced with G.E. Star computer. These images were acquired in dynamic byte mode, 128 x 128 matrix size, every minute for 40 minutes. Delayed images for this region and of both legs were also taken at 90 minutes and time activity curves from comparable regions of interest over the inguinal area bilaterally were generated. Three patterns emerged: 1-normal lymph flow (12 patients) characterized by symmetrical or nearly symmetrical early appearance of lymphatics (medial bands) with visualization of inguinal and pelvic lymph nodes in both early and delayed images. Time activity curves showed step ladder rise, in "pulses" every three to four minutes. 2-enhanced lymph flow pattern (6 patients) was characterized by rapid movement of radiolabelled albumin through
dilated lymphatics, occasionally with subcutaneous pooling, and both larger and more numerous inguinal and pelvic nodes on the lymphedematous side. 3-obstructed lymph flow (5 patients) was characterized by subcutaneous
pooling, absent lymphatics, (medial bands) and flat, time activity curve on the lymphedematous side (only background activity) and absent inguinal and pelvic nodes. On delayed images, where lymphatic obstruction was incomplete there was delayed appearance of inguinal pelvic nodes which were fewer and smaller compared to the nonedematous side. Intradermal injection of Tc-99m HSA is a useful technique to examine peripheral lymph dynamics in patients with chronic lymphedema of the legs. The procedure is safe, reliable, readily interpretable and may be repeated.


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