Can a cardiac MRI (Cardiac Magnetic Resonance Imaging) rule out pericarditis or microvascular disease in a patient with ongoing chest pain, negative troponins, and no electrocardiogram (EKG) changes?

Cardiac MRI for Ruling Out Pericarditis and Microvascular Disease

Yes, cardiac MRI can effectively rule out pericarditis with high sensitivity (94-100%), but it cannot reliably rule out microvascular disease in your clinical scenario. 1

Cardiac MRI Performance for Pericarditis

For pericarditis detection, cardiac MRI is highly effective and should be pursued if clinical suspicion remains:

• CMR demonstrates 94-100% sensitivity for detecting pericardial inflammation, making it an excellent tool to rule out this diagnosis when negative 1
• The ACC/AHA guidelines specifically recommend CMR when there is diagnostic uncertainty or to determine the presence and extent of pericardial inflammation and fibrosis 1
• CMR with late gadolinium enhancement (LGE) can show characteristic changes of acute myopericarditis, especially when performed within 2 weeks of presentation 1
• CMR can detect pericardial enhancement, thickening, and effusions that may not be apparent on echocardiography 1, 2
• In patients with troponin-positive chest pain and unobstructed coronaries, CMR provides a diagnosis in approximately 87-90% of cases, with pericarditis/myocarditis being the most common finding (60%) 3, 4

Key CMR findings for pericarditis include:

• Pericardial enhancement or thickening on LGE sequences 1
• Increased T2-weighted signal indicating pericardial edema 1
• Pericardial effusion (though absence doesn't exclude pericarditis) 1

Cardiac MRI Limitations for Microvascular Disease

Cardiac MRI cannot reliably rule out microvascular disease (coronary microvascular dysfunction) in your scenario:

• Standard rest CMR without stress perfusion will not detect microvascular dysfunction 1
• Vasodilator stress perfusion CMR would be required to assess for microvascular ischemia, but this is relatively contraindicated in patients with recent or active chest pain 1
• The ACR guidelines note that inotropic stress agents like dobutamine are "relatively contraindicated in patients with recent or active chest pain," limiting stress CMR utility in acute presentations 1
• First-pass contrast-enhanced perfusion CMR can demonstrate myocardial perfusion abnormalities, but requires stress challenge to unmask microvascular disease 1

Clinical Algorithm for Your Patient

Given ongoing chest pain with negative troponins and normal EKG:

1. Obtain transthoracic echocardiography first - This is the Class I recommendation to assess for pericardial effusion, wall motion abnormalities, and valvular issues 1

2. If echocardiography is inconclusive and pericarditis remains suspected, proceed with CMR - This provides definitive assessment of pericardial inflammation 1, 2

3. For microvascular disease assessment, defer stress testing until chest pain resolves - Once acute symptoms stabilize (typically 3+ days), vasodilator stress CMR can be performed safely to evaluate for ischemia 1

Important Caveats

Common pitfalls to avoid:

• A normal echocardiogram does not exclude pericarditis - Pericardial effusion is only present in ~60% of acute pericarditis cases 5
• Minimally elevated troponin can occur in pericarditis (up to 50% of cases) and doesn't necessarily indicate worse prognosis 1, 6
• CMR timing matters - Perform within 2 weeks of symptom onset for optimal detection of acute inflammation 1
• Pericardial friction rub is highly specific but only audible in one-third of cases, so its absence doesn't exclude pericarditis 5
• The clinical diagnosis in troponin-positive patients with unobstructed coronaries shows poor concordance between experienced cardiologists (κ=0.47), highlighting the value of CMR for definitive diagnosis 3

In summary: Order CMR now to rule out pericarditis, but recognize it will not assess for microvascular disease without stress perfusion, which should be deferred until the acute chest pain resolves.