Diagnosis of deep vein thrombosis using platelet scintigraphy

We reviewed the usefulness of platelet scintigraphy, in which autologous platelets labeled with indium-111-oxine reveal thrombotic activity, for evaluating deep vein thrombosis (DVT).

During the past 2 years, 39 cases with DVT were enrolled in this study. DVT was definitely diagnosed by color duplex scanning, platelet scintigraphy or both in all cases. For semiquantitative analysis, we estimated the ratio of accumulation in the abnormal region to that in the normal vein on the other side, and defined an abnormal accumulation ratio as over 1.2.

Abnormal accumulation ratio showing active DVT was recognized in 30 cases (77%), and showed a good correlation with clinical symptoms. In addition, in 19 cases with crural DVT, platelet scintigraphy showed abnormal accumulation ratio in 16 cases (84%), while duplex scanning detected thrombi in 13 cases (68%). In cases with abnormal accumulation ratio, thrombolytic and anticoagulant therapy were very effective for improving clinical symptoms as well inducing regression of the accumulation ratio.

Platelet scintigraphy was very useful for the diagnosis and treatment of DVT and for evaluation of the effect of anticoagulant therapy. Limitations in the definite diagnosis of deep vein thrombosis (DVT) have been apparent for more than three decades. During the last decade, duplex scanning has reached a high level of accuracy and has been considered the gold standard in the diagnosis of DVT, instead of venography. However, duplex scanning and venography demonstrates only the anatomic alterations associated with venous lesions. In contrast, in platelet scintigraphy, the labeled platelets are incorporated directly into the thrombus and can reveal thrombus activity. We noticed that autologous platelets labeled with indium-111-oxine accumulated on fresh lesions of DVT. This observation suggested two applications of this technique: 1) evaluation of the role of platelets in the pathophysiologic characteristics of DVT; and 2) monitoring the effects of anticoagulant therapy.