The Lake Louise Criteria for Magnetic Resonance Imaging Diagnosis of Myocarditis is a diagnostic tool used specifically in the field of cardiology. This calculator is applied to patients suspected of having myocarditis, an inflammation of the heart muscle. The Lake Louise Criteria utilizes cardiac magnetic resonance imaging (MRI) findings to aid in the diagnosis of myocarditis. 

The clinical utility of this calculator lies in its ability to provide a standardized approach to the interpretation of cardiac MRI findings in suspected myocarditis, thereby aiding in the accurate diagnosis and subsequent management of this condition. 

Exclusion criteria for the use of the Lake Louise Criteria include patients who are contraindicated for MRI such as those with certain types of implanted medical devices (e.g., certain pacemakers or neurostimulators), severe kidney disease, or claustrophobia. Additionally, it may not be applicable in cases where myocarditis is not the primary differential diagnosis.

Lake Louise criteria for magnetic resonance imaging diagnosis of myocarditis

# Criteria
 A. Regional or global myocardial signal intensity increase in T2-weighted images (+1)
B. Increased global myocardial early gadolinium enhancement ratio between myocardium and skeletal muscle in gadolinium-enhanced T1-weighted images (+1)
C. At least one focal lesion with non-ischemic regional distribution in inversion recovery-prepared gadolinium-enhanced T1-weighted images (late gadolinium enhancement) (+1)

# Conditions
- score <= 0
- score <= 1
- score <= 2
- score <= 3
- score == 0