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Response of mouse brain perfusion to hypo‐ and hyperventilation measured by arterial spin labeling
Author(s) -
Oosterlinck W. Wouter,
Dresselaers T.,
Geldhof V.,
Van Santvoort A.,
Robberecht W.,
Herijgers P.,
Himmelreich U.
Publication year - 2011
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.23060
Subject(s) - hyperventilation , cerebral blood flow , hypercapnia , thalamus , arterial spin labeling , hypocapnia , perfusion , anesthesia , tidal volume , medicine , respiratory rate , chemistry , cardiology , respiratory system , heart rate , blood pressure , radiology
We aimed to setup a noninvasive and well‐controlled methodology for evaluation of the cerebrovascular response in mice (C57BL/6J; 12 weeks). Therefore we applied a normo‐, hypo‐, and hyperventilation paradigm combined with arterial spin labeling and monitoring of the expired CO 2 (expCO 2 ) ( n = 7) or arterial pCO 2 (apCO 2 ) ( n = 12). Reducing the tidal volume by 25% and the respiratory rate by 20% resulted in hypercapnia (apCO 2 from 33 ± 6 mmHg to 64 ± 16 mmHg). Increasing the respiratory rate by 25% and the tidal volume by 20% decreased apCO 2 to 22 ± 5 mmHg. Cerebral blood flow (CBF) was 82 ± 21, 163 ± 41 and 64 ± 18 mL/100 g/min during normo, hypo‐, and hyperventilation, respectively (midbrain). The correlation of apCO 2 and CBF levels resulted in a cerebrovascular response of 2.7 ± 0.3, 2.1 ± 0.3, 2.1 ± 0.3, and 3.7 ± 0.5 mL/100 g/min/mmHg for midbrain, cortex, hippocampus and thalamus, respectively. As expCO 2 levels were correlated with apCO 2 ( r 2 = 0.86; n = 4) and CBF ( r 2 = 0.67) a cerebrovascular response based on simultaneously recorded CBF and expCO 2 levels could be derived (3.3 ± 0.5, 2.5 ± 0.4, 3.0 ± 0.4, and 4.5 ± 0.6 mL/100 g/min/mmHg; order as above). A cross‐over experiment resulted in similar responses. In conclusion, this protocol allows evaluating basal CBF and cerebrovascular response in mice under well‐controlled conditions by simply changing ventilator settings and correlating CBF with apCO 2 and/or simultaneously obtained expCO 2 . Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.