Comparison of Immune Checkpoint Inhibitor (ICI) Myocarditis and Non-ICI Myocarditis Using Cardiovascular Magnetic...

Area of Science:

• Cardiology
• Immunology
• Radiology

Background:

• Differentiating immune checkpoint inhibitor (ICI) myocarditis from non-ICI myocarditis is crucial for patient management.
• Cardiovascular magnetic resonance (CMR) is a key diagnostic tool for acute myocarditis.
• The utility of CMR in distinguishing between ICI and non-ICI myocarditis requires further investigation.

Purpose of the Study:

• To determine if Cardiovascular magnetic resonance (CMR) can differentiate between immune checkpoint inhibitor (ICI) myocarditis and non-ICI myocarditis.
• To compare cardiac function, fibrosis, and edema using CMR in patients with ICI myocarditis versus non-ICI myocarditis.

Main Methods:

• A retrospective cohort study involving 54 patients (26 ICI myocarditis, 28 non-ICI myocarditis).
• Clinical CMR assessments included cines for cardiac function, native T1-mapping, extracellular volume (ECV) fraction, and late gadolinium enhancement (LGE) for fibrosis, and native T2-mapping for edema.
• Analysis compared quantitative parametric mapping values and LGE patterns between the two groups.

Main Results:

• ICI myocarditis patients were significantly older than non-ICI myocarditis patients (75 vs. 39 years).
• Left ventricular ejection fraction, native myocardial T1, T2 values, and ECV were similar between groups.
• Non-ICI myocarditis patients showed a higher frequency of LGE (89% vs. 52%), but the LGE pattern was similar in both groups.

Conclusions:

• Quantitative parametric mapping methods using CMR may not be sufficient to differentiate between ICI and non-ICI myocarditis.
• The study highlights the need for further research to establish the role of CMR in diagnosing ICI myocarditis.
• Current CMR findings suggest overlapping imaging characteristics between ICI and non-ICI myocarditis.