3D whole heart k-space-based super-resolution cardiac T1 mapping using rotated stacks

Area of Science:

• Cardiovascular Magnetic Resonance Imaging
• Medical Image Reconstruction
• Quantitative Imaging

Background:

• Standard cardiac T1 mapping often yields 2D images with limited through-plane resolution due to signal-to-noise ratio (SNR) and cardiac motion.
• Previous super-resolution reconstruction (SRR) methods for 3D T1 maps were restricted to the ventricles.
• Acquiring high-resolution isotropic T1 maps of the whole heart remains a challenge.

Purpose of the Study:

• To develop and validate a k-space-based SRR technique for generating high-resolution 3D whole-heart cardiac T1 maps.
• To overcome the limitations of previous methods by enabling whole-heart coverage with improved resolution.
• To assess the accuracy, precision, and image quality of the proposed T1 mapping approach.

Main Methods:

• Acquisition of rotated, multi-slice stacks with high in-plane resolution and low through-plane resolution in a long-axis orientation.
• Utilizing a k-space-based SRR framework that incorporates the complete acquisition model for reconstruction.
• Incorporating motion estimation and correction for cardiac and respiratory motion between breath-holds.
• Validation through simulations, phantom experiments, and application to ten healthy subjects.

Main Results:

• Achieved whole-heart 3D T1 maps with 1.3 mm isotropic resolution within a comparable acquisition time to previous lower-resolution methods.
• Enabled T1 measurements in small structures like the atrial wall.
• Demonstrated accurate (P>0.4, R²>0.99) and precise T1 values (SD 64.32 ± 22.77 ms).
• Improved edge sharpness by 6.20% (simulation) and 4.73% (phantom).
• Increased contrast-to-noise ratio between septum and blood pool by 14.50% compared to image-space SRR.

Conclusions:

• The proposed k-space-based SRR method successfully generates high-resolution 3D whole-heart T1 maps.
• This technique significantly enhances visualization of cardiac structures, including smaller atrial and ventricular walls.
• The approach offers a valuable tool for quantitative cardiac MRI, improving diagnostic capabilities.