Robust dual-module velocity-selective arterial spin labeling (dm-VSASL) with velocity-selective saturation and...

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Neuroimaging

Background:

• Conventional velocity-selective arterial spin labeling (VSASL) suffers from artifacts and suboptimal background suppression, limiting its accuracy.
• These limitations, including sensitivity to eddy currents, diffusion, and motion, compromise temporal SNR and quantification in VSASL.
• Despite being delay-insensitive, VSASL's practical application is hindered by these challenges.

Purpose of the Study:

• To develop and evaluate a novel dual-module VSASL (dm-VSASL) strategy for improved SNR efficiency and temporal SNR.
• To enhance background suppression, particularly for cerebrospinal fluid (CSF), in VSASL.
• To assess the robustness and artifact sensitivity of dm-VSASL compared to existing methods.

Main Methods:

• A novel dual-module VSASL (dm-VSASL) strategy was developed with a balanced gradient configuration for label/control image acquisition.
• The strategy was applied to both VS saturation (VSS) and VS inversion (VSI) labeling schemes.
• dm-VSASL performance was compared against single-module and previous multi-module VSASL schemes using simulations and in vivo experiments, with pulsed ASL as a reference.

Main Results:

• dm-VSASL demonstrated more robust labeling and efficient background suppression across brain tissues, notably improving CSF signal.
• Significant reductions in artifacts and improvements in temporal SNR were observed with dm-VSASL.
• Compared to single-module VSASL, dm-VSASL improved temporal SNR by 90.8-94.9% in gray matter and 41.5-55.1% in white matter (P < .001 and P < .002, respectively).

Conclusions:

• The dual-module VSASL (dm-VSASL) strategy significantly enhances labeling robustness and reduces artifacts.
• dm-VSASL allows for efficient background suppression, leading to improved image quality.
• When implemented with VS inversion (VSI), dm-VSASL achieves the highest SNR efficiency among VSASL techniques, offering a powerful tool for accurate, delay-insensitive perfusion mapping.