Inclusion Criteria:

• Provide signed IC prior to undergoing any study procedures
• Be male or nonpregnant female, between the ages of 18 to 75 years, inclusive
• Have:A rest/stress SPECT imaging study (either exercise or pharmacologic stress) within 21 days of enrollment, using 99mTc-labeled tracers and showing reversible ischemia

• Female patients must:

  • be nonlactating,
  • no longer have child-bearing potential, either because they are post-menopausal (defined as amenorrhea ≥ 12 consecutive months, or because they have undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation or bilateral oophorectomy)

Exclusion Criteria:

• Presence of any condition that may disrupt and/or increase permeability of the BBB, including multiple sclerosis, Alzheimer's disease, Parkinson's disease, acute central nervous system (CNS) infection, CNS tumor, autoimmune disease affecting the CNS, or CNS inflammatory
• Current significant illness, pathology or physical examination or vital signs measurement-findings that could potentiate any adverse pharmacological event associated with a vasodilatory drug or any pathology that, in the opinion of the investigator, might confound the interpretation of the results of the study
• Known hypersensitivity to adenosine, dipyridamole or aminophylline
• Presence of any contraindications to exercise stress testing
• History of New York Heart Association Class III or IV Congestive Heart Failure (CHF)
• Any major surgery within 4 weeks prior to enrollment or planned within 2 weeks following completion of the 2-week telephone follow-up assessment
• Inability to tolerate IV medication.
• History of drug or alcohol abuse within the last year
• Participation in any investigational drug, device, or placebo study within 6 months prior to study enrollment