Antifibrin scintigraphy in the diagnostic evaluation of acute deep venous thrombosis

Abstract

Antifibrin scintigraphy is a new and innovative approach to the diagnosis of acute deep venous thrombosis (DVT). Many antifibrin monoclonal antibodies (Mo-Abs) have been described, but only two, 59D8 and T2G1s, have undergone broad preclinical or clinical investigation. Both of these MoAbs recognize an epitope on the amino terminal end of fibrin. The epitope for 59D8 and T2G1s is available for binding only on newly formed, acute thrombi. Preclinical studies have confirmed the specificity of these MoAbs for acute DVT, and have demonstrated their ability to image experimentally induced DVT. Preliminary clinical studies in patients with signs or symptoms of DVT have evaluated indium-111 59D8 Fab and technetium-99m T2G1s Fab'. Fragments of the intact MoAbs are employed to promote faster blood clearance and to reduce immunogenicity. The initial clinical studies indicate that antifibrin scintigraphy has a diagnostic accuracy approaching 90%. Antifibrin scintigraphy has the potential for overcoming many of the deficiencies of both invasive (contrast venography) and noninvasive (Doppler/ultrasound, impedance plethysmography) methods for detecting DVT. With a single procedure, it provides an accurate and rapid evaluation of both lower extremities, both above and below the knee. Because of its unique specificity for acute DVT, it should have excellent potential for use in patients with suspected acute, recurrent DVT, a condition difficult to diagnose by all currently employed tests for DVT.