Pseudo-continuous transfer insensitive labeling technique.

Area of Science:

• Neuroimaging
• Medical Physics
• Physiology

Background:

• Pulsed arterial spin labeling (PASL) using transfer insensitive labeling technique (TILT) enables multislice cerebral blood flow (CBF) mapping.
• TILT's effectiveness is challenged by slice profile errors, arterial transit time sensitivity, and low signal-to-noise ratio (SNR).
• Magnetization transfer effects in TILT are managed using concatenated radiofrequency pulses.

Purpose of the Study:

• To introduce a novel pseudo-continuous arterial spin labeling (ASL) approach, pseudo-continuous transfer insensitive labeling technique (pTILT), to overcome TILT's limitations.
• To enhance perfusion imaging by improving tagging, flow sensitivity, and labeling flexibility.
• To evaluate pTILT's performance in healthy volunteers for both resting-state and functional tasks.

Main Methods:

• Developed pTILT by adapting the original TILT method into a pseudo-continuous ASL framework.
• Utilized nonadiabatic pulses for pseudo-continuous tagging.
• Acquired perfusion maps in healthy volunteers during resting and functional tasks.

Main Results:

• Successfully demonstrated perfusion maps using pTILT in healthy volunteers.
• pTILT exhibits sensitivity to both slow and fast blood flows, offering flexible labeling geometries.
• While pTILT's SNR is lower than inversion-based pseudo-continuous ASL, it is comparable to inversion-based PASL techniques.

Conclusions:

• pTILT represents a significant advancement in perfusion imaging, addressing key limitations of the original TILT method.
• The novel pTILT approach offers improved perfusion acquisition capabilities, including enhanced flow sensitivity and labeling flexibility.
• pTILT provides a viable alternative for CBF mapping, with SNR performance comparable to established PASL methods.