Arterial spin labeling of cerebral perfusion territories using a separate labeling coil

Abstract

Purpose: To obtain cerebral perfusion territories of the left, the right, and the posterior circulation in humans with high signal-to-noise ratio (SNR) and robust delineation. Materials and Methods: Continuous arterial spin labeling (CASL) was implemented using a dedicated radio frequency (RF) coil, positioned over the neck, to label the major cerebral feeding arteries in humans. Selective labeling was achieved by flow-driven adiabatic fast passage and by tilting the longitudinal labeling gradient about the Y-axis by θ = ± 60°. Results: Mean cerebral blood flow (CBF) values in gray matter (GM) and white matter (WM) were 74 ± 13 mL·100 g-1·minute -1 and 14 ± 13 mL·100 g-1·minute -1 respectively (N = 14). There were no signal differences between left and right hemispheres when θ = 0° (P > 0.19), indicating efficient labeling of both hemispheres. When θ = +60°, the signal in GM on the left hemisphere, 0,07 ± 0.06%, was 92% lower than on the right hemisphere, 0.85 ± 0.30% (P < 1 × 10-9), while for θ = -60°, the signal in the right hemisphere, 0.16 ± 0.13%, was 82% lower than on the contralateral side, 0.89 ± 0.22% (P < 1 × 10-10). Similar attenuations were obtained in WM. Conclusion: Clear delineation of the left and right cerebral perfusion territories was obtained, allowing discrimination of the anterior and posterior circulation in each hemisphere. © 2008 Wiley-Liss, Inc.