In Vivo Detection of Circulating Clots in Patients With Thromboembolism

Inclusion Criteria * Men and women, 18 years old and older. * Evidence of current venous or arterial thromboembolic disease diagnosed by standard of care clinical, radiographic, or laboratory testing or acute ischemic stroke. * Informed consent provided by the subject. Exclusion Criteria * Pulmonary embolus with a need for mechanical ventilation or other ventilator support (may be on oxygen delivered by nasal cannula or mask at an FiO2 of ≤ 0.40) * Acute coronary syndrome (including unstable angina) * Significant cardiac arrhythmia (may have atrial fibrillation controlled with medication) * Intracardiac thrombus * Any embolus or thrombus requiring vascular surgery or interventional radiology to attempt acute embolectomy or thrombectomy * Sickle cell disease with vaso-occlusive crisis * Sepsis or life-threatening infection * Traumatic injury requiring hospitalization (within 30 days prior to enrollment) * Pregnancy or breastfeeding * Severe mental illness * Other conditions deemed by the investigators to put the subject at greater risk