F-GP1 is a derivative of elarofiban with a high affinity to activated platelet glycoprotein IIb/IIIa (GPIIb/IIIa) and favorable in vivo characteristics for thrombus imaging in preclinical models. We aimed to explore the detection rate of thromboembolic foci with F-GP1 positron emission tomography/computed tomography (PET/CT) in patients with acute venous thromboembolism (VTE), and to evaluate the safety, biodistribution, pharmacokinetics, and metabolism ofF-GP1. We studied patients who had signs or symptoms of acute deep vein thrombosis (DVT) of the leg or acute pulmonary embolism (PE) within 14 days prior toF-GP1 PET/CT, and had thromboembolic foci confirmed by conventional imaging ( = 10 for DVT and = 10 for PE). Dynamic whole-body PET/CT images were acquired for up to 140 minutes after injection of 250 MBq ofF-GP1. F-GP1 PET/CT was well tolerated without any drug-related adverse events, and showed high initial uptake in spleen, kidney, and blood pool, followed by rapid clearance. The overall image quality was excellent and allowed interpretation in all patients.F-GP1 PET/CT identified thromboembolic foci in all 20 patients with either DVT or PE. Vessel-level analysis revealed that F-GP1 PET/CT detected 89% (68/76) of vessels with DVT, and 60% (146/245) for PE. Importantly,F-GP1 PET/CT showed increased uptake in 32 vessels that were not detected by conventional imaging, of which 25 were located in distal veins of the lower extremity in 12 patients. A positive correlation was found between F-GP1 uptake and P-selectin-positive circulating platelets ( = 0.656, = 0.002).F-GP1 is a promising PET tracer for imaging acute VTE in patients. F-GP1 PET/CT may identify thrombi in distal veins of the leg, where conventional imaging has limitations.

Background18F-GP1 is a novel positron emission tomography (PET) tracer that targets glycoprotein IIb/IIIa receptors on activated platelets. The study objective was to explore the feasibility of directly imaging acute arterial thrombosis (AAT) with 18F-GP1 PET/computed tomography (PET/CT) and to quantitatively assess 18F-GP1 uptake. Safety, biodistribution, pharmacokinetics and metabolism were also evaluated.MethodsAdult patients who had signs or symptoms of AAT or had recently undergone arterial intervention or surgery within 14 days prior to 18F-GP1 PET/CT were eligible for inclusion. The AAT focus was demonstrated by conventional imaging within the 5 days prior to 18F-GP1 administration. Whole-body dynamic 18F-GP1 PET/CT images were acquired for up to 140 min after injection of 250 MBq of 18F-GP1. Venous plasma samples were analysed to determine 18F-GP1 clearance and metabolite formation.ResultsAmong the ten eligible patients assessed, underlying diseases were abdominal aortic aneurysm with endovascular repair (n = 6), bypass surgery and stent placement (n = 1), endarterectomy (n = 1), arterial dissection (n = 1) and acute cerebral infarction (n = 1). 18F-GP1 administration and PET/CT procedures were well tolerated, with no drug-related adverse events. All patients showed high initial 18F-GP1 uptake in the spleen, kidney and blood pool, followed by rapid clearance. Unmetabolised plasma 18F-GP1 levels peaked at 4 min post-injection and decreased over time until 120 min. The overall image quality was sufficient for diagnosis in all patients and AAT foci were detected in all participants. The 18F-GP1 uptake in AAT foci remained constant from 7 min after injection and began to separate from the blood pool after 20 min. The median standardised uptake value of AAT was 5.0 (range 2.4–7.9) at 120 min post-injection. The median ratio of standardised uptake value of AAT foci to the mean blood pool activity was 3.4 (range 2.0–6.3) at 120 min.Conclusions18F-GP1 is a safe and promising novel PET tracer for imaging AAT with a favourable biodistribution and pharmacokinetic profile.Trial registrationClinicalTrials.gov identifier: NCT02864810, Registered August 3, 2016.Electronic supplementary materialThe online version of this article (10.1186/s13550-018-0471-8) contains supplementary material, which is available to authorized users.