This is a prospective clinical study aiming to investigate the efficacy of Magnetocardiography (MCG) in detecting myocardial ischemia in patients of a suspected non-ST-elevation-acute coronary syndrome (NSTE-ACS) by using Single photon emission computed tomography (SPECT) as the gold standard for determining the presence and severity of myocardial ischemia.

Inclusion Criteria:

• Age 18 years or older;
• Patients with symptoms of myocardial ischemia such as angina pectoris, who have CAG showing <70% stenosis at the most severe site or CTA showing non-severe stenosis
• Signed informed consent.

Exclusion Criteria:

• Patients with absolute or relative contraindications to SPECT-loaded myocardial perfusion, including acute myocardial infarction within 48 hours, significant left main coronary artery stenosis, bronchial asthma, and adenosine injection allergy;
• Patients with Non-ischemic dilated cardiomyopathy, or hypertrophic cardiomyopathy, or moderate or severe valvular disease;
• Patients with Hemodynamic instability (systolic blood pressure<90 mmHg, or who requires vasoactive drugs), or patients with tachyarrhythmia, Ⅱdegree atrioventricular block and above that have not returned to normal;
• Patients who have severe renal abnormality with eGFR <30 ml/min, or patients who are on dialysis;
• Patients with malignant tumors with predicted survival of less than 1 year;
• Pregnant or breastfeeding women;
• Patients who are unable to enter the MCG device, who are unable to perform MCG examination due to interference from metal implants or other reasons, or who are deemed by the investigators to be unsuitable for enrollment.

Chest pain patients who have CAG showing <70% stenosis at the most severe site or CTA showing non-severe stenosis