Updated Lake Louise Criteria Calculator – CMR Diagnosis of Myocarditis

Clinical calculation support · Verify results before clinical use

CMR tissue-characterization assessment

Select the radiological interpretation for each available sequence. A positive finding in a category is sufficient to fulfil that category.

0/2Categories

T2-based criterion — myocardial edema

At least one positive T2-based finding fulfils this category.

T2 mapping Use sequence- and scanner-specific reference values and the interpreting laboratory's validated range.

T2-weighted imaging Assess myocardial edema using the acquired T2-weighted technique and local interpretation criteria.

T1-based criterion — myocardial injury

At least one positive T1-based finding fulfils this category.

Native T1 mapping Interpret against locally validated, field-strength- and sequence-specific reference values.

Extracellular volume (ECV) Interpret using local reference limits and appropriate hematocrit/contrast-enhanced mapping methodology.

Late gadolinium enhancement (LGE) Count a non-ischemic pattern of myocardial injury; an ischemic-pattern LGE alone does not fulfil this myocarditis criterion.

Supportive CMR findings

These findings support the overall assessment but do not replace either main Lake Louise category.

LV systolic dysfunction / wall-motion abnormality

Pericardial abnormality May indicate concomitant pericardial involvement (e.g., effusion or pericardial edema/LGE).

0/2Main criteria

CMR classification

Not yet assessable

Select the available T1- and T2-based findings to generate the assessment.

Interpretation and clinical contextThis calculator organizes CMR findings; it does not independently diagnose myocarditis.

Category statusT2-based: not assessed. T1-based: not assessed.

About the Updated Lake Louise Criteria

The 2018 updated Lake Louise Criteria (LLC) use a multiparametric CMR approach to identify non-ischaemic myocardial inflammation. The principal framework combines evidence of myocardial edema (T2-based) with evidence of myocardial injury (T1-based).

Main criteria

Category	Qualifying CMR markers	Target
T2-based	Increased regional/global myocardial T2 relaxation time on T2 mapping, and/or increased signal on T2-weighted imaging	Myocardial edema
T1-based	Non-ischaemic LGE, increased native T1, and/or increased ECV	Myocardial injury (including edema, hyperemia/capillary leak, necrosis or fibrosis)

How to interpret the combination

Both categories positive (2/2): provides strong CMR evidence of myocardial inflammation and has greater diagnostic specificity in an appropriate clinical setting.
Only one category positive (1/2): may support possible myocardial inflammation in an appropriate clinical scenario, but with lower specificity.
Neither category positive (0/2): updated LLC are not fulfilled on the assessed sequences. A negative CMR does not exclude myocarditis in every clinical context.

Pericardial abnormalities and LV systolic dysfunction are supportive findings, not substitutes for the two main categories.

Important technical considerations

There are no universal numeric cutoffs for native T1, T2 mapping, or ECV that can be applied across all scanners and sequences.
Use locally validated normal ranges matched to field strength, vendor, sequence, acquisition, and analysis method.
For LGE, assess the pattern and distribution; non-ischaemic myocardial LGE is the relevant T1-based marker.
Interpret CMR in the context of clinical presentation, biomarkers, ECG, echocardiography, timing, and differential diagnoses.
CMR diagnostic performance is generally better when performed early in the disease course; timing and disease phase may affect findings.

References

Ferreira VM, Schulz-Menger J, Holmvang G, et al.Cardiovascular Magnetic Resonance in Nonischemic Myocardial Inflammation: Expert Recommendations. J Am Coll Cardiol. 2018;72(24):3158–3176. DOI: 10.1016/j.jacc.2018.09.072.

2025 ESC Guidelines for the management of myocarditis and pericarditis.European Heart Journal. 2025. DOI: 10.1093/eurheartj/ehaf192.

Luetkens JA, Faron A, Isaak A, et al.Comparison of Original and 2018 Lake Louise Criteria for Diagnosis of Acute Myocarditis: Results of a Validation Cohort. Radiol Cardiothorac Imaging. 2019;1(3):e190010. DOI: 10.1148/ryct.2019190010.

Pan JA, Lee YJ, Salerno M.Diagnostic Performance of Extracellular Volume, Native T1, and T2 Mapping Versus Lake Louise Criteria by CMR for Detection of Acute Myocarditis: A Meta-Analysis. Circ Cardiovasc Imaging. 2018;11(7):e007598. DOI: 10.1161/CIRCIMAGING.118.007598.

Clinical disclaimer: This tool is an educational aid for organizing CMR findings according to the updated Lake Louise framework. It is not a stand-alone diagnostic test and does not replace expert CMR interpretation or clinical assessment. The 2025 ESC guideline classifies CMR as proven when both updated LLC categories are fulfilled, uncertain when only one is fulfilled, and rejected when CMR is negative; possible myocarditis may still be considered with one positive category in an appropriate clinical presentation. Consider alternative causes of myocardial edema or injury and the limitations of the acquired protocol.