[Isotope lymphography--possibilities and limits in evaluation of lymph transport]

Quantitative isotopic lymphscintigraphy is based on a combination of transmission- and emission scintigraphy correcting the different depths of lymph nodes. This method allows an exact estimation of lymph-transport in legs during standardised stress. The depth-corrected uptake in the lymph nodes expressed in percentage of the injected dose (D%) reflects the lymph-transport. After s.c. injection of 1 mCi of 99 m Tc-microcolloid (Nanocoll) the prefascial lymph-transport and after intramuscular (i.m.) injection the subfascial lymph-transport can be assessed. The stress consists of 15 minutes walking on a horizontal treadmill at a speed of 3.2 km/h. After s.c. injection all types of lymphedema can be diagnosed (average uptake in lymphedema 2.0 +/- 2.5 D%, in normal legs 14.3 +/- 4.2 D%; p < 0.001). The subfascial transport is much lower, only 7.7% of the prefascial transport. In healthy legs the uptake after i.m. injections is 1.1 +/- 0.8 D%, in postthrombotic syndrome the uptake decreases to 0.2 +/- 0.16 D% (p < 0.02). Lymphscintigraphy after i.c. injection of the colloid reveals contradictory results. The uptake is very low only in lymphedema with involvement of the whole leg. In distal and in secondary lymphedema the uptake is near the normal range. The clearance rate of the tracer from the depot is not reliable for diagnosing lymphedema. Information may be gained concerning the following points: quantitative measurement of lymph transport, routine diagnosis of lymphedema, follow-up in lymphedema, assessment of pre- and subfascial lymph-transport in patients with venous diseases, angiodysplasias etc., documentation of therapeutic effects.