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Assessment of human brain temperature by 1 H MRS during visual stimulation and hypercapnia
Author(s) -
Kauppinen Risto A.,
Vidyasagar Rishma,
Childs Charmaine,
Balanos George M.,
Hiltunen Yrjő
Publication year - 2008
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1204
Subject(s) - hypercapnia , stimulation , human brain , chemistry , nuclear magnetic resonance , neuroscience , physics , medicine , psychology , acidosis
Brain temperature is determined by the interplay between the cerebral metabolic rate of oxygen (CMRO 2 ) and cerebral blood flow (CBF). In this study, single‐voxel 1 H nuclear MRS, with an accuracy of ±0.2°C for temperature determination, was used at 3 T to measure human brain temperature during visual stimulation (which increases both CBF and CMRO 2 ) and hypercapnia (which increases CBF only). Visual stimulation had no detectable effect on brain temperature in the parenchyma showing blood oxygenation level dependent activation. Hypercapnia, leading to an increase in the end tidal CO 2 by 8 ± 2 mm Hg above the baseline, caused a short‐lasting decrease in brain temperature of 0.30 ± 0.33°C. These results indicate that increased CBF may be a key factor, bringing about a small decrease in brain temperature during brain activation. However, the increase in CBF is not sufficient to lower brain temperature in the presence of a concomitant increase in endogenous heat production. Copyright © 2007 John Wiley & Sons, Ltd.