Sequential changes of myocardial microstructure in patients postmyocardial infarction by diffusion-tensor cardiac MR:...

Area of Science:

• Cardiovascular Imaging
• Biomedical Engineering
• Cardiac MRI

Background:

• Myocardial infarction (MI) causes significant changes in left ventricular (LV) microstructure.
• Diffusion-tensor cardiac MRI (DT-CMR) can assess tissue integrity (mean diffusivity [MD], fractional anisotropy) and fiber architecture (helix angles).
• Understanding sequential microstructural changes post-MI is crucial for predicting functional recovery.

Purpose of the Study:

• To investigate sequential changes in myocardial microstructure using DT-CMR after recent MI.
• To explore the relationship between microstructural remodeling and macrostructural/functional changes in the LV post-MI.

Main Methods:

• DT-CMR was used to measure MD, fractional anisotropy, and helix angles.
• Cine gradient echo assessed LV function, and late gadolinium enhancement evaluated myocardial viability.
• Measurements were taken from recent to chronic MI stages in 17 male patients.

Main Results:

• The infarct-adjacent zone showed increased MD, decreased fractional anisotropy, and decreased mean helix angles compared to the remote zone.
• From recent to chronic MI, MD sequentially decreased, and fractional anisotropy increased.
• Improved wall thickening correlated with decreased MD and increased helix angles in specific LV zones.

Conclusions:

• DT-CMR demonstrates sequential zonal improvements in tissue integrity and fiber architecture remodeling post-MI.
• These microstructural improvements are associated with the recovery of zonal wall thickening of the LV.
• DT-CMR provides valuable insights into the dynamic nature of myocardial recovery after MI.