3D left ventricular strain from unwrapped harmonic phase measurements.

Area of Science:

• Cardiovascular Imaging
• Biomedical Engineering
• Medical Physics

Background:

• Accurate measurement of 3D left ventricular (LV) strain is crucial for assessing cardiac function.
• Tagged cardiac magnetic resonance imaging (MRI) provides data for strain analysis.
• Existing methods for 3D strain quantification can be time-consuming and complex.

Purpose of the Study:

• To validate a novel method for calculating 3D LV strain.
• The method utilizes phase-unwrapped harmonic phase (HARP) images from tagged cardiac MRI.
• To compare the new method against established techniques.

Main Methods:

• Tagged cardiac MRI was performed on 40 human subjects.
• Phase-unwrapped harmonic phase (HARP) images were computed and processed.
• Three-dimensional (3D) strain maps were generated and compared to feature-based (FB) and standard HARP methods.

Main Results:

• Full 3D strain maps were computed across the cardiac cycle within approximately 30 minutes per study.
• The strain from unwrapped phase (SUP) method showed high agreement with the FB technique (standard deviation <5%).
• Peak circumferential strain measured by SUP correlated strongly with the HARP technique (>83%).

Conclusions:

• The SUP technique enables efficient reconstruction of 3D LV strain maps from tagged MRI.
• This method offers a reasonable balance of time and user interaction compared to other 3D analysis approaches.
• The validated SUP technique can enhance the analysis of cardiac mechanics.