Thrombosis detection using radionuclide techniques.

Radionuclides have been used in the evaluation of intravascular thrombosis for several years. The most widely accepted nonimaging technique is I-125 labeled fibrinogen. It is commonly used for patients who have a high probability of developing a thrombus (e.g., those undergoing surgery). Other techniques are emerging as having value in thrombosis detection. These techniques include radionuclide venography and clot localization scanning techniques utilizing the affinity of clot for small radiolabeled particles, as well as imaging techniques using I-131 labeled fibrinogen. More recently, a number of the above-mentioned techniques have been applied to patient problems. The FDA ban on commercial radiolabeled fibrinogen in the United States has promoted the development of alternative techniques and the use of autologous fibrinogen. A number of other techniques for thrombosis detection have also been explored on a more experimental basis. They include the use of thrombolytic agents such as streptokinase, urokinase, and white blood cells, as well as platelets. The common lung or pulmonary perfusion scan using macroaggregates of albumin or microspheres radiolabeled also gives information as to the presence of thrombosis of embolus within the pulmonary arteries, by showing the effect upon the perfusion pattern. This review will explore in detail the principles, as well as the present and prospective usefulness of the techniques currently available.