Imaging of 111In-labelled platelets--a new method for the diagnosis of deep vein thrombosis

A radionuclide method for detecting established thrombi at all sites in the lower limb would have several advantages. Autologous platelets were labelled with 150 microCi (5.5 MBq) indium-111-oxine and re-injected into patients who were imaged with a gamma camera and data processed by a medical computer. Areas of increased uptake on imaging were correlated with the sites of thrombi identified by bilateral ascending venography. Venography in 27 patients identified 12 unilateral and 5 bilateral thrombi. On the day following the re-injection of labelled platelets, imaging identified thrombi at 13 sites in 24 limbs giving an overall correlation with venography of 84.4 per cent, correlation for the calf and thigh being 79.5 per cent and 89.1 per cent respectively. In the thigh 57.1 per cent of thrombi were identified by imaging and 52.9 per cent in the calf. Activity over thrombi was at least 20 per cent higher than in adjacent areas or at similar sites in the contralateral leg. Herapin therapy is considered to affect the detection of deep vein thrombus adversely by this technique. The technique offers a useful method for the diagnosis of both early and established thrombi at any site in the lower limb.