Improved pseudo-continuous arterial spin labeling for mapping brain perfusion.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Neuroimaging

Background:

• Conventional continuous ASL (CASL) and pseudo-continuous ASL (pCASL) are used for brain perfusion mapping.
• The original pCASL method suffers from reduced ASL signal due to equilibrium magnetization perturbation by the null pulse.

Purpose of the Study:

• To introduce and evaluate a modified pCASL (mpCASL) technique for enhanced brain perfusion imaging.
• To address the signal loss issue in pCASL by modifying the null pulse.

Main Methods:

• mpCASL performance was assessed using numerical simulations and experimental validation.
• In vivo brain perfusion images were acquired using MRI at 4 Tesla in four volunteers.
• ASL signal intensity, image contrast, and scan-rescan reproducibility were compared across CASL, pCASL, and mpCASL methods.

Main Results:

• mpCASL demonstrated higher ASL signal intensity compared to CASL and pCASL.
• Perfusion maps generated with mpCASL exhibited superior image contrast.
• mpCASL showed improved reproducibility in repeat scans over the other ASL methods.

Conclusions:

• The modified null pulse in mpCASL effectively reduces equilibrium magnetization perturbation.
• mpCASL leads to improved brain perfusion images with higher signal, contrast, and reproducibility.