Quantitative analysis of hypertrophic myocardium using diffusion tensor magnetic resonance imaging

Area of Science:

• Cardiovascular Imaging
• Biophysics
• Cardiac Pathology

Background:

• Systemic hypertension is a primary cause of left ventricular hypertrophy (LVH).
• LVH involves structural remodeling of the myocardium, potentially leading to dysfunction.
• Understanding microstructural changes is crucial for managing hypertensive heart disease.

Purpose of the Study:

• To analyze myocardial fiber and laminar sheet orientation in hypertrophic versus normal rat hearts.
• To quantify microstructural alterations in the myocardium due to hypertensive LVH.
• To investigate the potential for reversing or managing LVH-associated cardiac dysfunction.

Main Methods:

• Diffusion tensor magnetic resonance imaging (DT-MRI) was employed on ex vivo rat hearts.
• A cardiac microstructure atlas was created from normal (WKY) rat hearts.
• Hypertrophic (SHR) and normal hearts underwent registration to the atlas, followed by tensor field reorientation using PPD.

Main Results:

• Significantly increased myocardial fiber derangement was observed in hypertrophic hearts (mean dispersion 38.7° vs. 34.8°).
• Increased dispersion of laminar sheet normal was found in hypertrophic hearts (54.8° vs. 51.8°).
• These findings demonstrate significant alterations in myocardial fiber and laminar sheet structure in hypertensive LVH.

Conclusions:

• Hypertensive LVH is associated with substantial derangement of myocardial fiber and laminar sheet architecture.
• DT-MRI provides a quantitative method to assess microstructural changes in cardiac hypertrophy.
• Targeting these structural abnormalities may offer therapeutic strategies for hypertensive heart disease.