Brachial Artery Ultrasound Imaging: A Repeatability Study

Inclusion Criteria: 1. Men and women, ≥18 years old 2. Eastern Cooperative Oncology Group/Zubrod score performance status of 0, 1, or 2, determined within 7 days prior to FMD testing on Study Day 1 (Visit 1) 3. Written informed consent understood and signed; understanding of study procedures and ability to comply with them for the length of the study Exclusion Criteria: 1. Body mass index (BMI) \>50 kg/m2 2. Mid-upper arm circumference of arm selected for FMD testing \<17 cm or \>42 cm 3. Sinus arrhythmia (RR intervals vary by \>50%), atrial fibrillation, atrial flutter, multifocal atrial tachycardia, frequent (\>1 per 10-sec strip) premature atrial or ventricular contractions (isolated, non-isolated, or alternating), documented by 12-lead ECG with rhythm strip at the time of subject screening. 4. Clinical signs and/or symptoms of active viral or bacterial infections 5. Resting tremor or inability to remain still for the duration of the testing period 6. Systolic blood pressure (SBP) at rest of \>170 mmHg or diastolic blood pressure (DBP) at rest of ≥110 mmHg. 7. Diabetic subjects - Type I or II 8. Previous intolerable adverse reaction(s) to vascular testing using an upper extremity occlusive pneumatic cuff