Purpose: Lymphoscintigraphy is the criterion-standard method for diagnosing lymphedema, and there is no universally standardized imaging modality. In our center, we use a new approach: rest/stress intradermal lymphoscintigraphy.
Methods: We tested 231 consecutive patients with suspected lymphedema. All patients were studied after a complex physical therapy program to reduce edema. Two doses of 99m Tc-nanocolloid were injected intradermally. Two static planar scans were taken at rest following tracer injection. Next, patients performed an isotonic muscular exercise for 2 minutes followed by postexercise scans. Subsequently, a prolonged exercise was performed for 30 to 40 minutes, after which delayed scans were taken. Abnormal patterns were distinguished into minor or major findings, according to severity.
Results: We identified superficial lymphatic vessels and regional lymph nodes in approximately 80% of limbs. Deep vessels were visualized in 26% of limbs. Minor findings were reported in 22.7% of limbs examined, whereas major findings were reported in 53.2% of limbs.
Conclusion: We observed major findings including lymph stagnation, extravasation, or dermal backflow in a significantly higher percentage of limbs with secondary lymphedema than in primary. We also observed the deep lymphatic pathways in a significantly higher percentage of limbs with primary lymphedema. Intradermal radiotracer injection, combined with isotonic muscular exercise, may offer a better and faster imaging of lymphatic pathways, evaluating the effects of muscular exercise on lymphatic drainage. Based on the in-depth information of the lymphatic pathways provided by rest/stress intradermal lymphoscintigraphy, microsurgeons can obtain important functional information to perform supermicrosurgical lymphatic-venous anastomosis or vascularized lymph node transfer.
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