Angina is a common clinical symptom of ischemic heart disease, affecting up to 11 million people in the United States alone, and 112 million people globally. Despite this, 4 in 10 patients undergoing elective coronary angiography for angina and ischemia do not have evidence of obstructive coronary artery disease (CAD). This condition of ischemia with no obstructive CAD (INOCA) is associated with high clinical and economic morbidity, as these patients have a higher rate of repeat procedures and hospitalizations, worse quality of life, future adverse cardiovascular events and frequent time missed from work. The overall objective of this study is to develop and validate a non-invasive algorithm for diagnosis and management of patients with INOCA and suspected microvascular dysfunction centered around cardiac PET MPI. A secondary goal of the study is to assess for improvement in patient symptoms, function and quality of life from PET-guided management of CMD in patients with INOCA. This study will take place at Mount Sinai Morningside in the PET and CTunit on the 3rd floor. The sub-study will occur at Mount Sinai Morningside Cath Lab on the 3rd floor. The study will enroll an estimated total of 70 subjects, 12 of which will also participate in the sub-study. The study is estimated to last 2 years.