3D GRASE PROPELLER: improved image acquisition technique for arterial spin labeling perfusion imaging

Area of Science:

• Neuroimaging
• Medical Physics
• Radiology

Background:

• Arterial spin labeling (ASL) is a noninvasive MRI technique for quantitative cerebral blood flow (CBF) measurement.
• Traditional ASL methods use 2D imaging, but 3D gradient echo and spin echo (GRASE) offers better signal-to-noise ratio and spatial coverage.
• A key limitation of 3D GRASE is through-plane blurring due to T2 decay.

Purpose of the Study:

• To introduce and evaluate a novel 3D GRASE technique combined with PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) for ASL.
• To minimize through-plane blurring in 3D GRASE ASL without compromising perfusion sensitivity or increasing scan time.
• To assess the clinical utility of 3D GRASE PROPELLER for routine neuroimaging.

Main Methods:

• Implementation of a 3D GRASE sequence with PROPELLER trajectory for ASL.
• Acquisition of full-brain perfusion images using a pulsed ASL preparation sequence at 3 × 3 × 5 mm³ voxel size.
• Data collection from five healthy subjects on a GE 1.5T scanner, with scan times under 4 minutes per subject.

Main Results:

• The 3D GRASE PROPELLER technique effectively reduced through-plane blurring compared to standard 3D GRASE.
• Cerebral blood flow quantification showed good agreement with conventional 3D gradient echo and spin echo methods.
• Improved anatomical details, high repeatability, and robustness against motion were observed.

Conclusions:

• 3D GRASE PROPELLER is a promising ASL technique that overcomes the blurring limitations of standard 3D GRASE.
• The method provides accurate CBF quantification with enhanced image quality and motion resilience.
• This technique is suitable for routine clinical use in neuroimaging due to its efficiency and reliability.