Venous thrombosis a controlled study on the performance of scintigraphy with 99TcmHMPAOlabelled platelets versus venography

Thirtythree patients with symptoms and signs of a deep venous thrombosis DVT were examined by contrast venography and radionuclide imaging with 99Tcmhexamethylpropyleneamineoxime 99TcmHMPAOlabelled autologous platelets. There were 13 patients on heparin therapy and 20 without anticoagulation during the scintigraphy. Scintigraphy consisted of blood pool imaging at 5 to 20 min and accumulation imaging at 2, 46 and 1824 h. In scintigraphy a positive finding was either a defect of radioactivity in the immediate blood pool phase or a hot spot indicative of accumulation of platelets in later phases. Fifteen out of 23 patients positive by venography were also positive by scintigraphy. Five of the eight false negative patients were on heparin treatment, two probably had DVT which were not quite fresh. The venography negative patients were also negative on scintigraphy. Nine out of 12 patients without anticoagulation had positive platelet accumulation compared with two out of 11 patients on heparin therapy. This difference was statistically significant P<0.025. The sensitivity and specificity of platelet scintigraphy were 65 and 100, respectively, in all patients and 83 and 100 in patients without anticoagulation. Our results suggest that scintigraphy with 99TcmHMPAOlabelled platelets is a useful alternative in diagnosing DVT in patients in whom a standard contrast Xray venograph is contraindicated or otherwise unsuccessful.