Reduced resolution transit delay prescan for quantitative continuous arterial spin labeling perfusion imaging.

Area of Science:

• Medical Imaging
• Neuroimaging
• Physiology

Background:

• Arterial spin labeling (ASL) perfusion MRI is susceptible to artifacts and quantification errors due to uncertain arterial transit time (ATT).
• ATT uncertainty is pronounced in diverse clinical populations with altered cerebral blood flow, such as reduced or collateral flow.
• Conventional ATT measurement methods prolong scan times and reduce perfusion image sensitivity.

Purpose of the Study:

• To develop a rapid, reduced-resolution ASL prescan for accurate measurement of ATT.
• To describe methods for utilizing ATT information to optimize and quantify high-resolution continuous ASL (CASL) perfusion images.
• To assess the feasibility and impact of this approach on perfusion and ATT quantification.

Main Methods:

• A novel, low-spatial-resolution ASL prescan was implemented for rapid ATT mapping.
• Techniques were developed to integrate ATT data for optimizing high-resolution CASL perfusion imaging.
• The method was validated in normal volunteers.

Main Results:

• The proposed ASL prescan enables rapid measurement of ATT.
• Transit delay heterogeneity was observed across different brain regions in normal volunteers.
• Failure to account for ATT heterogeneity leads to significant perfusion quantification errors.
• The approach demonstrated feasibility for accurate perfusion and ATT quantification.

Conclusions:

• A rapid, reduced-resolution ASL prescan effectively measures ATT, crucial for accurate perfusion MRI.
• This method mitigates quantification errors caused by ATT variations, particularly in heterogeneous flow conditions.
• The technique offers a feasible solution for improved perfusion and ATT quantification in clinical neuroimaging.