Radial simultaneous multi-slice CAIPI for ungated myocardial perfusion.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Technology
• Cardiovascular Imaging

Background:

• Simultaneous multi-slice (SMS) imaging accelerates MRI acquisition by capturing multiple slices concurrently.
• Radial CAIPI offers reduced aliasing artifacts compared to Cartesian SMS methods.
• Improving ungated cardiac perfusion imaging is crucial for efficient diagnostic workflows.

Purpose of the Study:

• To evaluate the utility of radial CAIPI with undersampling and constrained reconstruction for ungated cardiac perfusion MRI.
• To compare the performance of saturation recovery turboFLASH and steady-state SPGR sequences within this framework.
• To assess the feasibility of increased slice coverage without sacrificing temporal resolution.

Main Methods:

• Developed and tested a radial CAIPI framework incorporating data undersampling and constrained reconstruction.
• Acquired ungated cardiac perfusion data using both saturation recovery turboFLASH and steady-state SPGR sequences in animal and human subjects.
• Employed slice acceleration factors of two and three with a novel spatio-temporal reconstruction algorithm.

Main Results:

• Phantom and simulation studies indicated SPGR sequences may offer better contrast-to-noise ratio (CNR) than saturation recovery sequences under specific conditions.
• Both ungated radial CAIPI methods demonstrated good image quality, preserving contrast agent dynamics and anatomical detail.
• Simultaneous acquisition of three slices was feasible with promising results.

Conclusions:

• Ungated SMS acquisitions using radial CAIPI with turboFLASH or SPGR sequences are feasible, enhancing slice coverage without compromising temporal resolution.
• Constrained reconstruction techniques yield superior image quality for undersampled radial CAIPI data compared to SENSE-based SMS reconstruction.
• This approach holds potential for more efficient cardiac perfusion imaging.