Noninvasive Cardiac Imaging in Vasospastic Angina Korean Registry (NAVIGATOR)

Inclusion Criteria: * Subject is onset of angina-like attack at rest, during effort, or during rest and effort. * Subject has chest pain between night and early morning. * Subject is scheduled to undergo MDCTA. * Subject is an acceptable candidate for CAG with an EG provocation test. * Cardiac condition: BP\>90/60mmHg, ECG: sinus rhythm with regular, left ventricular ejection fraction\>55%, and resting heart rate\<100 beats/min. * Subject will be provided written informed consent. * Subject is willing to comply with study follow-up requirement. Exclusion Criteria: * Subject has clinical evidence of acute coronary syndrome. * Subject has evidence of significant narrowing (\>50% stenosis by CAG). * Subject has clinical evidence of cardiomyopathy or valvular heart disease. * Subject is hemodynamically unstable. * Subject has a history of PCI and CABG. * Subject is pregnant and/or breastfeeding or intends to become pregnant during the duration of the study. * Subject has known allergy to contrast medium. * Subject has renal insufficiency (serum creatine \>2.5 mg/dl).