Intradermal lymphoscintigraphy at rest and after exercise: a new technique for the functional assessment of the lymphatic system in patients with lymphoedema.

Aim: The aim of this study was to evaluate the effect of implementing a new technique, intradermal injection lymphoscintigraphy, at rest and after muscular exercise on the functional assessment of the lymphatic system in a group of patients with delayed or absent lymph drainage.

Methods: We selected 44 patients (32 women and 12 men; 15 of 44 with upper limb and 29 of 44 with lower limb lymphoedema). Thirty of 44 patients had bilateral limb lymphoedema and 14 of 44 had unilateral disease; 14 contralateral normal limbs were used as controls. Twenty-three patients had secondary lymphoedema after lymphadenectomy and the remaining 21 had idiopathic lymphoedema. Each of the 44 patients was injected with 50 MBq (0.3-0.4 ml) of (99m)Tc-albumin-nanocolloid, which was administered intradermally at the first interdigital space of the affected limb. Two planar static scans were performed using a low-energy general-purpose collimator (acquisition matrix 128 x 128, anterior and posterior views for 5 min), and in which drainage was slow or absent, patients were asked to walk or exercise for 2 min. A postexercise scan was then performed to monitor and record the tracer pathway and the tracer appearance time (TAT) in the inguinal or axillary lymph nodes.

Results: The postexercise scans showed that (i) 21 limbs (15 lower and six upper limbs) had accelerated tracer drainage and tracer uptake in the inguinal and/or axillary lymph nodes. Two-thirds of these showed lymph stagnation points; (ii) 27 limbs had collateral lymph drainage pathways; (iii) in 11 limbs, there was lymph drainage into the deeper lymphatic channels, with unusual uptake in the popliteal or antecubital lymph nodes; (iv) six limbs had dermal backflow; (v) three limbs did not show lymph drainage (TAT=not applicable). TAT=15 + or - 3 min, ranging from 12 to 32 min in limbs with lymphoedema versus 5 + or - 2 min, ranging from 1 to 12 min in the contralateral normal limbs (P<0.001).

Conclusion: Intradermal injection lymphoscintigraphy gives a better imaging of the lymph drainage pathways in a shorter time, including cases with advanced lymphoedema. In some patients with lymphoedema, a 2-min exercise can accelerate tracer drainage, showing several compensatory mechanisms of lymph drainage. The effect of the exercise technique on TAT and lymphoscintigraphy findings could result in a more accurate functional assessment of lymphoedema patients.