Improved pseudo-continuous arterial spin labeling for mapping brain perfusion.
OBJECTIVE
To investigate arterial spin labeling (ASL) methods for improved brain perfusion mapping. Previously, pseudo-continuous ASL (pCASL) was developed to overcome limitations inherent with conventional continuous ASL (CASL), but the control scan (null pulse) in the original method for pCASL perturbs the equilibrium magnetization, diminishing the ASL signal. Here, a new modification of pCASL, termed mpCASL is reported, in which the perturbation caused by the null pulse is reduced and perfusion mapping improved.


METHODS
improvements with mpCASL are demonstrated using numerical simulations and experiments. ASL signal intensity as well as contrast and reproducibility of in vivo brain perfusion images were measured in four volunteers who had MRI scans at 4 Tesla and the data compared across the labeling methods.


RESULTS
Perfusion maps with mpCASL showed, on average, higher ASL signal intensity and higher image contrast than those from CASL or pCASL. Furthermore, mpCASL yielded better reproducibility in repeat scans than the other methods.


CONCLUSIONS
The experimental results are consistent with the hypothesis that the new null pulse of mpCASL leads to improved brain perfusion images.
Nezamzadeh
Marzieh
M
Center for Imaging of Neurodegenerative Diseases, Veterans Affairs Medical Center, San Francisco, California 94121, USA. marzieh.nezamzadeh@ucsf.edu
Matson
Gerald B
GB
Young
Karl
K
Weiner
Michael W
MW
Schuff
Norbert
N
D000328:Adult; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010477:Perfusion; D015203:Reproducibility of Results; D013113:Spin Labels
D013113:Spin Labels