MRI mapping of cerebrovascular reactivity using square wave changes in end-tidal PCO2
✍ Scribed by Alex Vesely; Hiroshi Sasano; George Volgyesi; Ron Somogyi; Janet Tesler; Ludwik Fedorko; Jonathan Grynspan; Adrian Crawley; Joseph A. Fisher; David Mikulis
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 247 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0740-3194
- DOI
- 10.1002/mrm.1134
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✦ Synopsis
Cerebrovascular reactivity can be quantified by correlating blood oxygen level dependent (BOLD) signal intensity with changes in end-tidal partial pressure of carbon dioxide (PCO2). Four 3-min cycles of high and low PCO2 were induced in three subjects, each cycle containing a steady PCO2 level lasting at least 60 sec. The BOLD signal closely followed the end-tidal PCO2. The mean MRI signal intensity difference between high and low PCO2 (i.e., cerebrovascular reactivity) was 4.0 +/- 3.4% for gray matter and 0.0 +/- 2.0% for white matter. This is the first demonstration of the application of a controlled reproducible physiologic stimulus, i.e., alternating steady state levels of PCO2, to the quantification of cerebrovascular reactivity.