In phase II study, we will recruit subjects who had significant coronary stenosis on CTA. If the patients had significant stenosis, they will undergo coronary angiography to confirm the severity of stenosis. If they had coronary artery stenosis more than 75%, they will receive percutaneous coronary intervention with drug-eluting stent (DES). If they had intermediate lesion, their treatment option will be judged by the results of fractional flow reserve test. If they had coronary lesion less than 50%, they will be treated only by medication.