A Fast Magnetic Flux Density Measurement Method With Skip-Echo Acquired Turbo Spin Echo (SATE)

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Medical Physics

Background:

• Magnetic Resonance Electrical Impedance Tomography (MREIT) and Magnetic Resonance Current Density Imaging (MRCDI) require magnetic flux density (B_z) measurements.
• Conventional spin echo (SE)-based sequences for B_z acquisition are too slow for clinical use.
• Accelerated imaging techniques are crucial for advancing MREIT and MRCDI applications.

Purpose of the Study:

• To develop and validate a novel imaging sequence for rapid B_z measurements.
• To improve the efficiency and speed of B_z data acquisition for MREIT and MRCDI.
• To enable volumetric B_z mapping within clinically relevant time.

Main Methods:

• A Skip-Echo Acquired Turbo Spin Echo (SATE) sequence was developed by incorporating a skip-echo module before conventional Turbo Spin Echo (TSE) acquisition.
• Amplitude-modulated crusher gradients and specially selected radiofrequency (RF) pulse shapes were used in SATE to eliminate unwanted signal pathways and preserve signal integrity.
• SATE sequence efficiency and accuracy were evaluated using phantom experiments and compared against the multi-echo injection current nonlinear encoding (ME-ICNE) method.

Main Results:

• The SATE sequence demonstrated improved measurement efficiency compared to standard TSE sequences.
• SATE achieved data acquisition speeds up to 10-fold faster than conventional methods.
• Accurate volumetric B_z maps were successfully obtained in phantoms, pork, and human calf within clinically acceptable times.

Conclusions:

• The proposed SATE sequence offers a significant acceleration in B_z measurements.
• SATE provides a fast and effective method for volumetric B_z mapping.
• This accelerated approach greatly facilitates the clinical translation of MREIT and MRCDI techniques.