Calibrationless multi-slice Cartesian MRI via orthogonally alternating phase encoding direction and joint low-rank...

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging (MRI)
• Image Reconstruction

Background:

• Accelerated MRI acquisition is crucial for reducing scan times.
• Current multi-slice MRI methods face challenges with aliasing artifacts and reconstruction quality.
• Calibrationless reconstruction methods are desirable for practical MRI applications.

Purpose of the Study:

• To develop and evaluate a novel multi-slice MRI acquisition and reconstruction strategy for accelerated 2D Cartesian imaging.
• To improve image quality and reduce aliasing artifacts in accelerated multi-slice MRI.
• To enable calibrationless parallel imaging for multiple 2D slices.

Main Methods:

• Acquisition of multi-slice, multi-channel MRI data with orthogonally alternating phase encoding (PE) directions between adjacent slices.
• Application of random or uniform PE undersampling.
• Joint reconstruction using a low-rank multi-slice Hankel tensor completion (MS-HTC) approach.
• Evaluation using human brain MR data.

Main Results:

• The proposed method effectively suppressed aliasing artifacts at high acceleration factors.
• It outperformed existing MS-HTC approaches with consistent PE directions.
• Robust performance was observed with both uniform and random undersampling, without requiring central k-space lines.
• Improved image reconstruction quality was achieved.

Conclusions:

• The novel strategy leverages coil sensitivities and inter-slice image similarities for enhanced reconstruction.
• Orthogonally alternating PE directions significantly aid the low-rank completion process and improve image quality.
• This method is applicable to various undersampling schemes and facilitates practical, calibrationless Cartesian parallel imaging for multi-slice MRI.