Inclusion Criteria:

• * Age range 35-85 years
• * Presence of the metabolic syndrome defined by the National Cholesterol Education Program, Adult Treatment Panel III (NCEP ATP III) definition, with at least three of the following five criteria:
• * waist circumference \> 40 inches (men) or \>35 inches (women)
• * blood pressure \>130/80 mmHg
• * fasting triglyceride (TG) level \>150 mg/dL
• * fasting high-density lipoprotein (HDL) cholesterol level \<40mg/dL in men or \<50mg/dL in women
• * Fasting blood glucose \>100 mg/dL, or hemoglobin A1c greater or equal to 5.7%
• * Either one of the following:
• * Men ≤ 40 or women ≤ 50 years of age with no history or symptoms of ischemic heart disease, or
• * Men \>40 or women \>50 years of age with either one of the following
• * a coronary angiography within the past 24 months showing no significant coronary artery disease in a t least one major vessel, defined as \>50% stenosis of the left main coronary artery and/or \>70% stenosis of another major coronary vessel, or
• * a coronary artery calcium score obtained within the prior 24 months or if no prior calcium scan, one performed as a research study following consent with a Agatston score \<10 in at least one major coronary vessel.
• * IHE-induced %-change in coronary flow ≤13%

Exclusion Criteria:

• * Systolic blood pressure \<110 mm Hg
• * Current or anticipated use of long-acting nitrates, soluble guanylate cyclase (sGC) stimulators, or phosphodiesterase type 5 (PDE5) inhibitors
• * Hematocrit \<30%
• * Unable to understand the risks, benefits, and alternatives of participation so as to provide informed consent
• * Women who are pregnant.
• * Women with reproductive capacity not using an acceptable form of contraception
• * History of claustrophobia
• * Inability to lie flat and still for 45 minutes
• * Presence of non-magnetic resonance (MR)-compatible objects or devices, such as intra-orbital debris, intra-auricular implants, intra-cranial clips, an implanted defibrillator or a pacemaker
• * History as a machinist, welder, metal worker or a similar activity that poses the risk of metal exposure to the eyes