Imaging of experimental arterial thrombi with iodine-131-labeled fibrin-specific monoclonal antibody.

The applicability of anti-fibrin monoclonal antibody in detecting intra-circulatory blood clots was studied in 17 dogs in two groups: 13 dogs in the study group and 4 dogs in the control group. In the study group, dogs were punctured at the femoral artery and a thrombogenic coil was injected percutaneously to the iliac artery to induce blood clot. After 30 minutes, a dose of I-131 labeled anti-fibrin monoclonal antibody-3E6 (84-280 microCi) was injected intravenously. The dogs were imaged with a scinticamera at 6, 24 and 48 hours after antibody injection. In the control group, 3 dogs were studied with the same procedure but the I-131 labeled anti-fibrin monoclonal antibody was replaced with an I-131 labeled irrelevant monoclonal antibody. The remaining 1 dog for control was punctured and was injected with I-131 labeled anti-fibrin monoclonal antibody but no coil injection was performed. In the study group, 11 out of 13 dogs (85%) showed clot visualization at either 6 hours (4 dogs) or 24 hours (7 dogs) after anti-fibrin monoclonal antibody injection. There was no false positive results for the 4 dogs in the control group. Our studies showed that radiolabeled anti-fibrin monoclonal antibody may be a potential tool for noninvasive detection of intravascular blood clots.