Isotope lymphography: a new method of investigating the role of the lymphatics in chronic limb oedema.

A method of investigating the lymphatic system by radionuclide imaging in patients with chronic lower limb oedema is described. The clearance of 99mTc rhenium sulphur colloid from the interdigital space of 55 limbs and its appearance in the ilio-inguinal lymph nodes 30 min, 1, 2 and 3 h later has been measured using a gamma camera in 34 limbs (26 patients) with the clinical and radiological features of primary lymphoedema, 10 limbs (8 patients) with venous oedema and 12 control limbs (6 volunteers). On visual interpretation the sensitivity of this technique in diagnosing lymphoedema was 97 per cent and its specificity 100 per cent, while it clearly differentiated between lymphoedema and venous oedema. Estimation of the percentage uptake of the colloid in the ilio-inguinal lymph nodes at 1/2, 1, 2 and 3 h showed a markedly decreased lymph flow in the 34 lymphoedematous limbs and an increased flow in the 10 limbs with venous oedema. The results suggest that this technique can be used as a simple diagnostic outpatient technique in the investigation of chronic limb oedema.