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Age-Related Changes of Cerebral Autoregulation: New Insights with Quantitative T2′-Mapping and Pulsed Arterial Spin-Labeling MR Imaging

Age-Related Changes of Cerebral Autoregulation: New Insights with Quantitative T2′-Mapping and... BACKGROUND AND PURPOSE: Cerebral perfusion and O 2 metabolism are affected by physiologic age-related changes. High-resolution motion-corrected quantitative T2′-imaging and PASL were used to evaluate differences in deoxygenated hemoglobin and CBF of the gray matter between young and elderly healthy subjects. Further combined T2′-imaging and PASL were investigated breathing room air and 100% O 2 to evaluate age-related changes in cerebral autoregulation. MATERIALS AND METHODS: Twenty-two healthy volunteers 60–88 years of age were studied. Two scans of high-resolution motion-corrected T2′-imaging and PASL-MR imaging were obtained while subjects were either breathing room air or breathing 100% O 2 . Manual and automated regions of interest were placed in the cerebral GM to extract values from the corresponding maps. Results were compared with those of a group of young healthy subjects previously scanned with the identical protocol as that used in the present study. RESULTS: There was a significant decrease of cortical CBF ( P < .001) and cortical T2′ values ( P < .001) between young and elderly healthy subjects. In both groups, T2′ remained unchanged under hyperoxia compared with normoxia. Only in the younger but not in the elderly group could a significant ( P = .02) hyperoxic-induced decrease of the CBF be shown. CONCLUSIONS: T2′-mapping and PASL in the cerebral cortex of healthy subjects revealed a significant decrease of deoxygenated hemoglobin and of CBF with age. The constant deoxyHb level breathing 100% O 2 compared with normoxia in young and elderly GM suggests an age-appropriate cerebral autoregulation. At the younger age, hyperoxic-induced CBF decrease may protect the brain from hyperoxemia. ABBREVIATIONS: BOLD blood oxygen level–dependent deoxyHb deoxyhemoglobin GM gray matter GM frontoparietal frontoparietal cortex (automatic ROI) MPRAGE magnetization-prepared rapid acquisition of gradient echo OEF oxygen extraction fraction PASL pulsed arterial spin-labeling rCBF regional CBF http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png American Journal of Neuroradiology American Journal of Neuroradiology

Age-Related Changes of Cerebral Autoregulation: New Insights with Quantitative T2′-Mapping and Pulsed Arterial Spin-Labeling MR Imaging

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References (77)

Publisher
American Journal of Neuroradiology
Copyright
Copyright © 2012 by the American Society of Neuroradiology.
ISSN
0195-6108
eISSN
1936-959X
DOI
10.3174/ajnr.A3138
pmid
22700750
Publisher site
See Article on Publisher Site

Abstract

BACKGROUND AND PURPOSE: Cerebral perfusion and O 2 metabolism are affected by physiologic age-related changes. High-resolution motion-corrected quantitative T2′-imaging and PASL were used to evaluate differences in deoxygenated hemoglobin and CBF of the gray matter between young and elderly healthy subjects. Further combined T2′-imaging and PASL were investigated breathing room air and 100% O 2 to evaluate age-related changes in cerebral autoregulation. MATERIALS AND METHODS: Twenty-two healthy volunteers 60–88 years of age were studied. Two scans of high-resolution motion-corrected T2′-imaging and PASL-MR imaging were obtained while subjects were either breathing room air or breathing 100% O 2 . Manual and automated regions of interest were placed in the cerebral GM to extract values from the corresponding maps. Results were compared with those of a group of young healthy subjects previously scanned with the identical protocol as that used in the present study. RESULTS: There was a significant decrease of cortical CBF ( P < .001) and cortical T2′ values ( P < .001) between young and elderly healthy subjects. In both groups, T2′ remained unchanged under hyperoxia compared with normoxia. Only in the younger but not in the elderly group could a significant ( P = .02) hyperoxic-induced decrease of the CBF be shown. CONCLUSIONS: T2′-mapping and PASL in the cerebral cortex of healthy subjects revealed a significant decrease of deoxygenated hemoglobin and of CBF with age. The constant deoxyHb level breathing 100% O 2 compared with normoxia in young and elderly GM suggests an age-appropriate cerebral autoregulation. At the younger age, hyperoxic-induced CBF decrease may protect the brain from hyperoxemia. ABBREVIATIONS: BOLD blood oxygen level–dependent deoxyHb deoxyhemoglobin GM gray matter GM frontoparietal frontoparietal cortex (automatic ROI) MPRAGE magnetization-prepared rapid acquisition of gradient echo OEF oxygen extraction fraction PASL pulsed arterial spin-labeling rCBF regional CBF

Journal

American Journal of NeuroradiologyAmerican Journal of Neuroradiology

Published: Dec 1, 2012

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