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J Magn Reson Imaging. 2012 Aug;36(2):312-21. doi: 10.1002/jmri.23658. Epub 2012 Apr 27.

Comparison of pulsed and pseudocontinuous arterial spin-labeling for measuring CO2 -induced cerebrovascular reactivity.

Author information

1
Institut de génie biomédical, Département de physiologie, Université de Montréal, Montreal, Quebec, Canada. felipe.tancredi@umontreal.ca

Abstract

PURPOSE:

To compare the performance of pulsed and pseudocontinuous arterial spin-labeling (PASL and pCASL) methods in measuring CO(2) -induced cerebrovascular reactivity (CVR).

MATERIALS AND METHODS:

Subjects were scanned using both ASL sequences during a controlled hypercapnia procedure and visual stimulation. CVR was computed as the percent CO(2) -induced increase in cerebral blood flow (Δ%CBF) per mmHg increase in end-tidal PCO(2) . Visually evoked responses were expressed as Δ%CBF. Resting CBF and temporal signal-to-noise ratio were also computed. Regionally averaged values for the different quantities were compared in gray matter (GM) and visual cortex (VC) using t-tests.

RESULTS:

Both PASL and pCASL yielded comparable respective values for resting CBF (56 ± 3 and 56 ± 4 mL/min/100g) and visually evoked responses (75 ± 5% and 81 ± 4%). Values of CVR determined using pCASL (GM 4.4 ± 0.2, VC 8 ± 1 Δ%CBF/mmHg), however, were significantly higher than those measured using PASL (GM 3.0 ± 0.6, VC 5 ± 1 Δ%CBF/mmHg) in both GM and VC. The percentage of GM voxels in which statistically significant hypercapnia responses were detected was also higher for pCASL (27 ± 5% vs. 16 ± 3% for PASL).

CONCLUSION:

pCASL may be less prone to underestimation of CO(2) -induced flow changes due to improved label timing control.

PMID:
22544711
DOI:
10.1002/jmri.23658
[Indexed for MEDLINE]

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