Magnetic Resonance & Optical Spectroscopy Validation

Inclusion Criteria: * Male or female * Age 18 - 89 * Healthy (self assessed) * Weight under 350lbs * Able to walk 50 yards without stopping * Able to travel to hospital for study visits * Able to follow a 3-step command * Able to remain in magnetic resonance (MR) scanner for up to 2 hours Exclusion Criteria: * Have internal metal medical devices, including cardiac pacemakers, aortic or cerebral aneurysm clips, artificial heart valves, ferromagnetic implants, shrapnel, wire sutures, joint replacements, bone or joint pins/rods/screws, metal fragments in your eye, or non-removable jewelry such as rings. * Are unwilling or unable to complete the imaging procedures for the duration of the magnetic resonance imaging (MRI) scan due to claustrophobia or other reason. * Serious mental illness that might preclude subject's ability to comply with study treatment * Are pregnant or plan on becoming pregnant in the next 8 weeks. * History of deep vein thrombosis (DVT) or pulmonary embolism (PE) * Varicose Veins * Known genetic factor (Factor V Leiden, etc.) or hypercoagulable state, including cancer, leukemia - such as chronic myelocytic leukemia (CML), hemoglobinopathies - such as sickle-cell disease and multiple myeloma and other proteinopathies. * Diagnosed peripheral arterial or vascular disease * Family history of primary DVT or PE * Peripheral neuropathy * History of chronic venous stasis or lower extremity edema * Female taking hormonal birth control (oral or otherwise) AND smoke…