Nuclear molecular imaging of venous thromboembolism: targeting clot-specific molecular components for improved diagnosis and management.

Venous thromboembolism (VTE), manifesting as deep vein thrombosis and pulmonary embolism, is a common, recurrent and potentially fatal condition. Anticoagulation remains the cornerstone of therapy, yet determining optimal treatment duration (eg, decision to shorten or extend anticoagulant treatment) is difficult due to the uncertain balance between long-term bleeding risk and recurrence. Future advances in vascular nuclear molecular imaging could critically help support this decision-making process. Current VTE diagnostic imaging relies on structural or perfusion-based techniques to infer thrombosis from abnormal vasculature structure or filling defects. While highly effective in localizing thrombi and assessing hemodynamic impact, they provide little insight into the biological activity or age of the clot. Consequently, anticoagulation strategies (duration and management) often proceed without direct clot-specific molecular information, potentially leading to suboptimal outcomes and increased risk of fatal bleeding. By contrast, nuclear VTE molecular imaging-using radiolabeled probes that selectively target key thrombus components such as fibrin or activated platelets-enables direct visualization of the clot. Single-photon emission computed tomography and positron emission tomography targeted imaging of VTE, beyond enhancing diagnostic accuracy, are expected to provide valuable insights into the structure, age, and activity of the clot. In particular, integration of these modalities with molecular findings from high throughput technologies could further elucidate the cellular and molecular mechanisms driving thrombus formation and resolution. When coupled with positron emission tomography's ability to assess molecular processes in vivo, such approaches may establish precision imaging biomarkers, bridging the gap between clot biology and clinical imaging, and ultimately transform VTE management from a structural or perfusion based to molecularly informed paradigm.