Changes in CBF-BOLD coupling detected by MRI during and after repeated transient hypercapnia in rat

Autor: Michael V. Dutka, Mark D. Does, B. Ellen Scanley, John C. Gore
Rok vydání: 2002
Předmět:
Zdroj: Magnetic Resonance in Medicine. 48:262-270
ISSN: 1522-2594
0740-3194
DOI: 10.1002/mrm.10217
Popis: The effect of hypercapnia on the cerebral metabolic rate of oxygen consumption (CMRO2) remains incompletely understood. This study examined the relationship between susceptibility (blood oxygenation level dependent (BOLD)) and perfusion-weighted (flow-sensitive alternating inversion recovery (FAIR)) MRI techniques both during induction of repeated transient hypercapnia (THC) and after return to normocapnia during whisker barrel functional activation. During induction of THC the FAIR signal became significantly elevated over control after 100 s of hypercapnia (P = 0.039), with a trend of increasing significance to 5 min (P = 0.000008). The FAIR signal in the activated cortex during subsequent normocapnia was significantly increased compared to pre-THC control after each successive period of THC. The mean grouped FAIR signal increased by 81% ± 63% after one exposure (P = 0.021), by 163% ± 55% after the second exposure (P = 0.0002), and by 240% ± 54% after the third exposure (P = 0.000002). The mean grouped BOLD signal trended upward, but did not increase significantly during or after exposure 1, 2, or 3. These data demonstrate increased uncoupling of perfusion-weighted from susceptibility imaging techniques, both in nonactivated cortex during hypercapnia, and with activation after multiple exposures to THC. These results are consistent with saturation of BOLD contrast as well as with increases in CMRO2 with stimulation after multiple exposures to THC. Magn Reson Med 48:262–270, 2002. © 2002 Wiley-Liss, Inc.
Databáze: OpenAIRE
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