Imaging characteristics of a novel technetium Tc 99m-labeled platelet glycoprotein IIb/IIIa receptor antagonist in patients with acute deep vein thrombosis or a history of deep vein thrombosis

Background: The diagnosis of recurrent deep vein thrombosis (DVT) is challenging. Imaging with radiolabeled peptides offers a new approach for detecting acute DVT. Technetium Tc 99m (Tc-99m)-apcitide binds with high affinity and specificity to the glycoprotein IIb/IIIa receptors expressed on activated platelets and, therefore, Tc-99m-apcitide scintigraphy should be negative with residual abnormalities caused by old, inactive thrombi and positive with new, active thrombi. Methods: In a prospective multicenter study, Tc-99m-apcitide imaging was performed on 38 patients with a newly diagnosed first DVT (group 1) and 40 patients with previous DVT, symptoms of postthrombotic syndrome, and chronic intraluminal abnormalities on ultrasonography (group 2). Images were interpreted in a blinded fashion by 2 experts and by newly trained nuclear medicine physicians. The sensitivity and specificity of Tc-99m-apcitide were determined by calculating the proportion of scans in group I patients that were read as "positive for acute DVT" and the proportion of scans in group 2 patients that were read as "negative for acute DVT," respectively. Results: When read by 2 experts, Tc-99m-apcitide had a sensitivity of 92% for both readers and specificities of 82% and 90%. Agreement between the experts was excellent. However, the accuracy and interreader agreement for newly trained nuclear medicine physicians were lower. Conclusions: Technetium Tc 99m-apcitide scintigraphy has potential utility in suspected recurrent DVT because it detects most acute thrombi and has few false-positive results in patients with previous DVT. However, the accuracy appears to depend on the training and experience of the interpreters.