In vivo thrombosis imaging in patients recovering from COVID-19 and pulmonary embolism

18F-GP1 is a novel radiotracer that binds to the platelet glycoprotein IIb/IIIa receptor and can image in vivo venous and arterial thrombi including deep vein thrombosis and pulmonary thromboemboli (1-3). We performed 18F-GP1 positron emission tomography-computed tomography (PET-CT) in 6 patients recovering from coronavirus disease (COVID)-19 with concomitant pulmonary embolism (median age 56 [interquartile range 53-60] years, 1 female, 5 requiring supplemental oxygen, no intensive care admissions) and undertook 18F-GP1 autoradiography of post-mortem lung tissue in 3 patients who had died from COVID-19 (4).
All patients demonstrated increased pulmonary 18F-GP1 uptake at a median of 69 (interquartile range 56-98) days after index presentation despite ongoing therapeutic oral anticoagulation. Focal intravascular uptake in persistent pulmonary embolism (A) was seen, as described previously (5). However, we also noted parenchymal uptake in regions of consolidation (B), as well as systemic uptake in an occluded saphenous vein coronary artery bypass graft and left ventricular thrombus which was subsequently confirmed on echocardiography (C). 18F-GP1 autoradiography also demonstrated focal and specific uptake co-localising to intravascular thrombus in patients with confirmed diffuse alveolar damage (D).
Protracted systemic and pulmonary thrombosis may be a feature of COVID-19 that can persist despite systemic therapeutic anticoagulation. 18F-GP1 is able to detect pulmonary and systemic arterial thrombosis and has potential applications across a broad range of pathologies.