Optimal diffusion weighting for in vivo cardiac diffusion tensor imaging

Area of Science:

• Cardiovascular Imaging
• Diffusion Tensor Imaging
• Medical Physics

Background:

• In vivo cardiac diffusion tensor imaging (cDTI) is crucial for assessing myocardial microstructure.
• Understanding the impact of diffusion weighting parameters is essential for accurate cDTI analysis.

Purpose of the Study:

• To investigate the influence of diffusion weighting on in vivo cDTI.
• To determine optimal parameters for improved cardiac diffusion tensor imaging.

Main Methods:

• Ten subjects underwent stimulated echo acquisition mode echo planar imaging with varying b-values (50-950 s·mm⁻², plus a 15 s·mm⁻² reference).
• Signal decay, signal-to-noise ratio, mean diffusivity, fractional anisotropy, and helical angle maps were analyzed.
• The effects of diffusion weighting on main and reference data were evaluated using all b-value pairs.

Main Results:

• Low b-values showed signal decay influenced by microvascular perfusion, which was mitigated by weighting reference images.
• Parameter maps improved with higher b-values until the signal neared the noise floor.
• Optimal parameters were identified as b=750 s·mm⁻² for main data and b=150 s·mm⁻² for reference data.

Conclusions:

• cDTI parameters (mean diffusivity, fractional anisotropy, helical angle) are significantly influenced by b-value choices.
• Optimized diffusion weighting improves parameter maps and reduces artifacts from microvascular perfusion.
• This optimized protocol enhances the sensitivity of cDTI for detecting cardiac pathologies.