Myocarditis MRI
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American Roentgen Ray Society Images of Myocarditis MRI |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Varun Kumar, M.B.B.S.
Overview
Cardiac MRI findings associated with myocarditis include myocardial inflammation, myocardial edema, capillary leak, and reduced left ventricular function.
Myocardial Inflammation
Myocardial inflammation associated with myocarditis appears as a high intensity signal with delayed gadolinium hyperenhancement on cardiac MRI (cMRI). [1]. While the cMRI pattern of gadolinium hyperenhancement in ST segment elevation myocardial infarction is transmural and extends from the endocardium to the epicardium, the patchy, non-segmental hyperenhancement pattern in myocarditis in contrast involves the epicardium and spares the subendocardium[2].
Cardiac Magnetic Resonance Imaging
Cardiac magnetic resonance imaging (cMRI or CMR) is useful in diagnosing myocarditis. cMRI demonstrates patchy, non-segmental inflammation by gadolinium hyperenhancement that is confined to the epicardial layer of the myocardium.[3]. When used in conjunction with the findings on coronary angiography, cMRI is useful in establishing the diagnosis of myocarditis. Among 79 patients with elevated cardiac biomakrkers who were suspected of having ACS and had normal coronary arteries on coronary angiography, 81% of the patients (including those with preserved ejection fraction) were diagnosed with myocarditis based on cMRI findings[4].
Gadolinium-enhanced magnetic resonance imaging (MRI) aid in assessing the extent of myocardial edema and inflammation. Extent of myocardial scarring has also been assessed with delayed enhanced MRI[5].
CMR was reported to have a sensitivity of 76%, specificity of 95.5%, and overall diagnostic accuracy of 85% when any-two of the following three sequences were used[1].
- Focal and global T2 signal intensity
- Myocardial global relative enhancement
- Delayed gadolinium enhancement
On CMR, inflammatory regions of cardia in myocarditis appear as contrast-enhanced regions. These are often observed on lateral and inferior walls and can be used to guide biopsy. Among 21 patients who underwent biopsy of contrast enhanced regions in a series in Germany, histopathologic findings in 19 patients were consistent with myocarditis[6].
CMR in myocarditis is generally indicated in patients with new or persisting symptoms, evidence for significant myocardial injury, and suspected viral etiology[7].
CMR findings in Myocarditis[7]:
- High T2 signal intensity areas suggests edema.
- Myocardial early gadolinium enhancement ratio (ratio between myocardium and skeletal muscle) ≥4.0 is suggestive of hyperemia and capillary leakage.
- Areas of delayed gadolinium enhancement suggesting myocardial injury or inflammation.
- Systolic dysfunction and pericardial effusion may also be noted on CMR
References
- ↑ 1.0 1.1 Abdel-Aty H, Boyé P, Zagrosek A, Wassmuth R, Kumar A, Messroghli D; et al. (2005). "Diagnostic performance of cardiovascular magnetic resonance in patients with suspected acute myocarditis: comparison of different approaches". J Am Coll Cardiol. 45 (11): 1815–22. doi:10.1016/j.jacc.2004.11.069. PMID 15936612.
- ↑ Skouri HN, Dec GW, Friedrich MG, Cooper LT (2006). "Noninvasive imaging in myocarditis". J. Am. Coll. Cardiol. 48 (10): 2085–93. doi:10.1016/j.jacc.2006.08.017. PMID 17112998.
- ↑ Skouri HN, Dec GW, Friedrich MG, Cooper LT (2006). "Noninvasive imaging in myocarditis". J. Am. Coll. Cardiol. 48 (10): 2085–93. doi:10.1016/j.jacc.2006.08.017. PMID 17112998.
- ↑ Monney PA, Sekhri N, Burchell T, Knight C, Davies C, Deaner A; et al. (2011). "Acute myocarditis presenting as acute coronary syndrome: role of early cardiac magnetic resonance in its diagnosis". Heart. 97 (16): 1312–8. doi:10.1136/hrt.2010.204818. PMID 21106555.
- ↑ Al-Mallah M, Kwong RY (2009). "Clinical application of cardiac CMR". Rev Cardiovasc Med. 10 (3): 134–41. PMID 19898290.
- ↑ Mahrholdt H, Goedecke C, Wagner A, Meinhardt G, Athanasiadis A, Vogelsberg H; et al. (2004). "Cardiovascular magnetic resonance assessment of human myocarditis: a comparison to histology and molecular pathology". Circulation. 109 (10): 1250–8. doi:10.1161/01.CIR.0000118493.13323.81. PMID 14993139.
- ↑ 7.0 7.1 Friedrich MG, Sechtem U, Schulz-Menger J, Holmvang G, Alakija P, Cooper LT; et al. (2009). "Cardiovascular magnetic resonance in myocarditis: A JACC White Paper". J Am Coll Cardiol. 53 (17): 1475–87. doi:10.1016/j.jacc.2009.02.007. PMC 2743893. PMID 19389557.