Myocardial Contractility Pattern Characterization in Radiation-Induced Cardiotoxicity Using Magnetic Resonance...

Area of Science:

• Cardiology
• Oncology
• Medical Imaging

Background:

• Radiation therapy (RT) is crucial for thoracic cancers but risks radiation-induced cardiotoxicity.
• Early detection of cardiac dysfunction post-RT is essential for patient management.
• Current methods may not be sensitive enough for subclinical changes.

Purpose of the Study:

• To evaluate a novel MRI-based contractility index (ContractiX) for early detection of RT-induced cardiotoxicity.
• To compare ContractiX sensitivity against other cardiac MRI parameters in a preclinical model.

Main Methods:

• Adult rats underwent image-guided thoracic RT or sham procedure.
• Cardiac MRI was performed at 8 and 10 weeks post-RT, measuring LVEF, mass, strain, and ContractiX.
• Analysis included ventricular torsion, diastolic strain rate, and mechanical dyssynchrony.

Main Results:

• LVEF and myocardial mass increased post-RT.
• Peak systolic strain and ContractiX significantly decreased post-RT, with ContractiX showing a greater relative reduction.
• ContractiX demonstrated an inverse nonlinear relationship with LVEF and decreased over time.

Conclusions:

• ContractiX is a sensitive, non-contrast MRI marker for subclinical cardiac dysfunction following RT.
• ContractiX is superior to other MRI measures for detecting early radiation-induced cardiotoxicity.