Tailored SMASH image reconstructions for robust in vivo parallel MR imaging

Area of Science:

• Magnetic Resonance Imaging
• Medical Physics
• Biomedical Engineering

Background:

• Simultaneous acquisition of spatial harmonics (SMASH) is an MRI technique that accelerates image acquisition by utilizing RF coil array data.
• SMASH replaces omitted gradient steps with spatial information, reducing scan times.
• Original SMASH reconstructions were limited by the need for specific coil configurations and image planes suitable for generating spatial harmonics.

Purpose of the Study:

• To describe key improvements in the SMASH reconstruction procedure.
• To enable high-quality SMASH imaging in oblique and double-oblique planes.
• To overcome limitations of earlier SMASH techniques.

Main Methods:

• Developed improved SMASH reconstruction algorithms by leveraging degrees of freedom in the spatial harmonic fit.
• Implemented tailored fitting procedures for enhanced accuracy.
• Applied a numerical conditioning approach based on new observations of noise propagation.

Main Results:

• Achieved high-quality SMASH image reconstructions in oblique and double-oblique planes.
• Demonstrated successful application in both phantom studies and high-resolution cardiac MRI.
• Overcame previous limitations related to specific imaging orientations and coil setups.

Conclusions:

• The described improvements significantly enhance the versatility and applicability of SMASH imaging.
• High-quality accelerated MRI is now feasible in complex oblique planes using SMASH.
• This advancement has implications for faster and more efficient cardiac MRI acquisition.