Authors: Felipe Kazmirczak, Chetan Shenoy
Publish Date: 1/18/2018
INDICATIONS AND PURPOSE OF THE SCAN
- The detection of presence and extent of myocardial ischemia is important to guide clinical care. Cardiovascular magnetic resonance is an established non-invasive imaging technique to evaluate myocardial ischemia.
WHY CMR (SPECIFIC ADVANTAGES)
- High special and temporal resolution enabling visualization of sub-endocardial ischemia.
- Good image quality independent of body habitus.
- CMR can identify ischemia by assessing perfusion and wall motion with stress.
- CMR has high accuracy and excellent prognostic data in the evaluation of ischemia.
- No ionizing radiation exposure.
EVIDENCE examples from the literature
- MR-IMPACT II Trial, a multicenter study of 533 patients comparing the accuracy of perfusion CMR, SPECT against the gold standard coronary angiography. Perfusion CMR was non-inferior compared to SPECT. 
- CE-MARC Trial, a single center study of 752 patients showed the perfusion CMR has higher sensitivity, positive predictive value and diagnostic accuracy when compared with SPECT.
- Jaarsma et al. in a meta-analysis of 37 studies showed that perfusion CMR has a sensitivity of 89% and specificity of 76%, similar to PET and superior to SPECT. 
- De Jong et al. in a meta-analysis of 28 studies comparing perfusion CMR to SPECT and stress echocardiography, perfusion CMR had superior accuracy. 
- Most recently, Danad et al. in a meta-analysis of 23 studies comparing perfusion CMR, SPECT, stress echocardiography, invasive coronary angiography, coronary computed tomography angiography, fractional flow reserve (FFR) derived from CCTA (FFRCT) to an invasive FFR reference standard found that perfusion CMR had the highest performance for the diagnosis of ischemia-causing CAD.
- Any implanted device that is not MRI conditional
- Inability to lie flat
- Inability to tolerate the scan
- Altered mental status/ inability to follow verbal commands in scanner
- Severe arrhythmias
- Patients renal disease and GFR<30 mL/min or patients with selected metallic implants or prostheses non-compatible to MRI. 
- Ischemic evaluation by CMR is appropriate in symptomatic patients with intermediate pre-test probability of CAD if ECG is uninterpretable or unable to exercise. 
- Current guidelines have a Class I or Class IIa recommendation for evaluation of ischemia in intermediate risk patients prior to invasive coronary angiography. [8, 9]
- Schwitter, J., et al., MR-IMPACT II: Magnetic Resonance Imaging for Myocardial Perfusion Assessment in Coronary artery disease Trial: perfusion-cardiac magnetic resonance vs. single-photon emission computed tomography for the detection of coronary artery disease: a comparative multicentre, multivendor trial. Eur Heart J, 2013. 34(10): p. 775-81.
- Greenwood, J.P., et al., Cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary heart disease (CE-MARC): a prospective trial. Lancet, 2012. 379(9814): p. 453-60.
- Jaarsma, C., et al., Diagnostic performance of noninvasive myocardial perfusion imaging using single-photon emission computed tomography, cardiac magnetic resonance, and positron emission tomography imaging for the detection of obstructive coronary artery disease: a meta-analysis. J Am Coll Cardiol, 2012. 59(19): p. 1719-28.
- de Jong, M.C., et al., Diagnostic performance of stress myocardial perfusion imaging for coronary artery disease: a systematic review and meta-analysis. Eur Radiol, 2012. 22(9): p. 1881-95.
- Danad, I., et al., Diagnostic performance of cardiac imaging methods to diagnose ischaemia-causing coronary artery disease when directly compared with fractional flow reserve as a reference standard: a meta-analysis. Eur Heart J, 2017. 38(13): p. 991-998.
- Levine, G.N., et al., Safety of magnetic resonance imaging in patients with cardiovascular devices: an American Heart Association scientific statement from the Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology, and the Council on Cardiovascular Radiology and Intervention: endorsed by the American College of Cardiology Foundation, the North American Society for Cardiac Imaging, and the Society for Cardiovascular Magnetic Resonance. Circulation, 2007. 116(24): p. 2878-91.
- Hendel, R.C., et al., ACCF/ACR/SCCT/SCMR/ASNC/NASCI/SCAI/SIR 2006 appropriateness criteria for cardiac computed tomography and cardiac magnetic resonance imaging: a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for Cardiac Imaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiology. J Am Coll Cardiol, 2006. 48(7): p. 1475-97.
- Task Force, M., et al., 2013 ESC guidelines on the management of stable coronary artery disease: the Task Force on the management of stable coronary artery disease of the European Society of Cardiology. Eur Heart J, 2013. 34(38): p. 2949-3003.
- Fihn, S.D., et al., 2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: executive summary: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation, 2012. 126(25): p. 3097-137.