Nuclear myocardial perfusion imaging is generally appropriate in patients with acute chest pain in which the diagnosis of acute coronary syndrome is unclear, to determine whether or not cardiac catheterization is indicated, or to determine prognosis. Appropriate Use Criteria (AUC) has been developed by the American College of Cardiology and is updated regularly. . Absolute contraindications to<unk><unk>  include acute myocardial infarction (within 2 days), unstable angina, and symptomatic heart failure. . The decision to perform nuclear myocardial perfusion imaging or<unk>  echo imaging generally depends upon local expertise. The benefit of nuclear imaging is that it can be performed in nearly 100% of patients, whereas echo<unk><unk>  is more limited by body habitus and the ability to obtain good imaging windows quickly after<unk> ing the patient. The benefit of echo<unk><unk>  is lower costs and no radiation exposure. The amount of radiation exposure from a<unk> -rest nuclear myocardial perfusion scan is typically 10 mSv or less for gamma camera based imaging (similar to a chest CT), and under 5 mSv for PET imaging.

PATIENTS WITH ACUTE CHEST PAIN: APPROPRIATE INDICATIONS
Patients with acute chest pain with possible acute coronary syndrome: a) ECG shows no ischemic changes, LBBB, or electronically ventricular paced rhythm; and b) negative to borderline elevated troponin levels.
In this setting, nuclear imaging is considered appropriate in both low-risk TIMI score and high-risk TIMI score patients
Patients with acute chest pain with possible acute coronary syndrome: a) ECG shows no ischemic changes, LBBB, or electronically ventricular paced rhythm; and b) negative to borderline elevated troponin levels.
In this setting, nuclear imaging is considered appropriate in both low-risk TIMI score and high-risk TIMI score patients
PATIENTS WITH ACUTE CHEST PAIN: INAPPROPRIATE INDICATIONS
Patients with definite acute coronary syndrome
Early<unk><unk>  contraindicated within 2 days after myocardial infarction
Patients with definite acute coronary syndrome
Early<unk><unk>  contraindicated within 2 days after myocardial infarction
THE BOTTOM LINE
Asymptomatic patients in need of risk stratification typically will undergo exercise ECG<unk>  only. Imaging is indicated only when the ECG is uninterpretable, the patient is unable to adequately exercise, or the pretest probability is intermediate or high.
Symptomatic patients with an uncertain diagnosis of acute coronary syndrome frequently undergo a<unk>  imaging procedure first, then depending upon the result, may or may not undergo cardiac catheterization.
The decision regarding<unk>  nuclear versus<unk>  echo is usually made based upon availability of local expertise.
Asymptomatic patients in need of risk stratification typically will undergo exercise ECG<unk>  only. Imaging is indicated only when the ECG is uninterpretable, the patient is unable to adequately exercise, or the pretest probability is intermediate or high.
Symptomatic patients with an uncertain diagnosis of acute coronary syndrome frequently undergo a<unk>  imaging procedure first, then depending upon the result, may or may not undergo cardiac catheterization.
The decision regarding<unk>  nuclear versus<unk>  echo is usually made based upon availability of local expertise.
ACS - Stress Testing
Harbor Macros: EKG
ACS - Risk Stratification
Unstable Angina - NSTEMI Guidelines
Age adjusted D-dimer
ECGs by Diagnosis
Bubble study
ADDIE system