Lake louise criteria

The cardio- MRT is currently the best non-invasive form of examination for myocarditis in particular. The diagnosis of myocarditis is still a challenge even today. For this reason, the findings of cardiac MRI are evaluated according to the so-called Lake-Louise criteria to compare myocardial changes and to standardize examination methods. These criteria were first established by a panel of experts in 2009 and have been adapted several times since then (Schuler 2017).

Typically, in the case of myocarditis, the following findings can be obtained by MRI:

• Edema: The T2-weighting shows inflamed areas in the fat-saturated T2-weighting hyperintensity (edema); a ratio > 1.9 is considered pathological and is an indication of myocardial edema (Niebauer 2015)
• Early Gadolinium Enhancement: In the presence of a capillary leak, hyperemia occurs (Pinger 2019). In the T1- weighting after administration of contrast medium, the uptake of contrast medium in the inflammatory areas is measured and compared to the contrast medium uptake of the skeletal muscles. The normal ratio is < 2.5, an Early- Gadolinium - Enhancement with a ratio of more than 4.0 or an absolute increase of > 45% indicate myocarditis (Herold 2018).
• Late Gadolinium Enhancement: A late gadolinium enhancement indicates irreversible cell damage (Pinger 2019). In the delayed enhancement sequences (also called late gadolinium enhancement) the inflammatory changed areas of the myocardium absorb contrast medium, which occurs in the acute phase of a myocarditis subepicardially, especially in the inferior lateral wall sections of the left ventricle.

In contrast to myocarditis, contrast agent enhancement in myocardial infarction is typically located subendocardially and can be assigned to a coronary artery supply area (Puls 2010).

In the case of inconspicuous findings on cardiac MRI and simultaneous clinical suspicion of myocarditis or if only one MRI criterion is positive, an MRI check after 1-2 weeks is recommended (Pinger 2019). Both the T1- weighting and the T2- weighting have their limits in case of a concomitant skeletal muscle inflammation (Niebauer 2015). The sensitivity of the Lake-Louise criteria is approx. 67 % and the specificity approx. 91 % (Schuler 2017). Cardiac MRI is thus the most sensitive and specified examination method for the diagnosis of myocarditis (Zajonz 2016).

In December 2018, the last revision of these criteria took place. In the process, the Late Gadolinium Enhancement was left as a single factor (Maintz 2019).

1. Herold G et al (2018) Internal Medicine Herold Verlag 233
2. Maintz D (2019) MRI for myocarditis diagnostics. MR 2019 Garmisch 18th MRT Symposium
3. Niebauer J (2015) Sports Cardiology. Springer Publishing House 179- 180
4. Pinger S (2019) Repetitorium Kardiologie: For clinic, practice, specialist examination. German medical publisher. 433- 435
5. Puls R et al (2010) Granular body MRI screening: findings and random findings. ABW Wissenschaftsverlag. 148- 149
6. Schuler G (2017) Physical activity and illness. de Gruyter Publishers 274 - 275
7. Zajonz T S (2016) Lake Louise Criteria of cardiac magnetic resonance imaging in acute and chronic myocarditis: correlation with histopathological parameters. Inaugural dissertation to obtain the degree of Doctor of Medicine of the Department of Medicine of the Justus Liebig University of Giessen