Inclusion Criteria:  Patients referred to diagnostic ICA after heart-CT Able to provide an informed consent. Age ≥ 18 years  Exclusion Criteria:  PCI, CABG, POBA or already acknowledge ischemic heart disease Acute coronary disease or AMI COPD or Asthma Pregnancy and breast breeding Contraindications to adenosine (severe asthma, complicated AV block, critical aortic stenosis, severe cardiac arrhythmias, severe valve diseases). Renal impairment with estimated glomerular filtration rate (eGFR) <40 ml / min. Allergy to X-ray contrast agents or severe metabolic disease. Donor heart, mechanical heart, or mechanical heart pump