Preliminary clinical studies have demonstrated detection of in vivo arterial and venous thrombi in patients with pulmonary thromboembolic disease, acute coronary syndrome, and bioprosthetic aortic valves.2–6 To our knowledge, there has only been 1 published case of detection of arterial thrombus in acute cerebral infarction with 18F-GP1 uptake.7 In this proof-of-concept pilot study, we aimed to determine whether 18F-GP1 PET and CT angiography has the potential to establish the presence, location, and origin of thrombus in patients with recent ischemic stroke. This evidence concerns the gene GTPBP1 and acute coronary syndrome.