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Cerebral blood flow response to acute hypoxic hypoxia.

Harris AD, Murphy K, Diaz CM, Saxena N, Hall JE, Liu TT, Wise RG - NMR Biomed (2013)

Bottom Line: However, this response, particularly at the tissue level, is not well characterised.The rate constant, temporal delay and magnitude of the CBF response were characterised using an exponential model for whole-brain and regional grey matter.The delay and rate constant for changes in R2 * were 24 s (95% CI: 21 s, 26 s) and 0.0392 s(-1) (95% CI: 0.0333 s(-1), 0.045 s(-1)), respectively, for the hypoxic response, and 12 s (95% CI: 10 s, 13 s) and 0.0921 s(-1) (95% CI: 0.0744 s(-1), 0.1098 s(-1)/) during the return to normoxia, confirming rapid changes in blood oxygenation with the end-tidal forcing system.

View Article: PubMed Central - PubMed

Affiliation: CUBRIC, School of Psychology, Cardiff University, Cardiff, UK.

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Cerebral blood flow (CBF) and R2* across whole-brain grey matter. Quantified CBF and the CBF modelled response are shown in light green and dark green, respectively. R2* over time and the modelled response are shown in pink and red, respectively. The time-series data for CBF and R2* were averaged into 11-s time bins for display purposes.
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fig04: Cerebral blood flow (CBF) and R2* across whole-brain grey matter. Quantified CBF and the CBF modelled response are shown in light green and dark green, respectively. R2* over time and the modelled response are shown in pink and red, respectively. The time-series data for CBF and R2* were averaged into 11-s time bins for display purposes.

Mentions: According to the model fitting of the group-averaged data, across grey matter, CBF increased from 76.1 mL/100 g/min (95% CI: 75.5, 76.7) to 87.8 mL/100 g/min (95% CI: 86.7, 89.6), with a rate constant of 0.0035 s–1 (95% CI: 0.0019, 0.0046) and a delay of 185 s (95% CI: 132, 230). This corresponds to a 15.4% increase in CBF. The parameters from the fitting (and the 95% CIs on these fits showing the reliability or noise in the parameter fit) across the regions are given in Table 2. The CBF and R2* time-course and model fits for all grey matter are shown in Fig. 4. The R2* response was more rapid than the CBF response, with a rate constant of 0.0392 s–1 and a delay of 24 s calculated for the transition to hypoxia (Table 3, Fig. 4).


Cerebral blood flow response to acute hypoxic hypoxia.

Harris AD, Murphy K, Diaz CM, Saxena N, Hall JE, Liu TT, Wise RG - NMR Biomed (2013)

Cerebral blood flow (CBF) and R2* across whole-brain grey matter. Quantified CBF and the CBF modelled response are shown in light green and dark green, respectively. R2* over time and the modelled response are shown in pink and red, respectively. The time-series data for CBF and R2* were averaged into 11-s time bins for display purposes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4114548&req=5

fig04: Cerebral blood flow (CBF) and R2* across whole-brain grey matter. Quantified CBF and the CBF modelled response are shown in light green and dark green, respectively. R2* over time and the modelled response are shown in pink and red, respectively. The time-series data for CBF and R2* were averaged into 11-s time bins for display purposes.
Mentions: According to the model fitting of the group-averaged data, across grey matter, CBF increased from 76.1 mL/100 g/min (95% CI: 75.5, 76.7) to 87.8 mL/100 g/min (95% CI: 86.7, 89.6), with a rate constant of 0.0035 s–1 (95% CI: 0.0019, 0.0046) and a delay of 185 s (95% CI: 132, 230). This corresponds to a 15.4% increase in CBF. The parameters from the fitting (and the 95% CIs on these fits showing the reliability or noise in the parameter fit) across the regions are given in Table 2. The CBF and R2* time-course and model fits for all grey matter are shown in Fig. 4. The R2* response was more rapid than the CBF response, with a rate constant of 0.0392 s–1 and a delay of 24 s calculated for the transition to hypoxia (Table 3, Fig. 4).

Bottom Line: However, this response, particularly at the tissue level, is not well characterised.The rate constant, temporal delay and magnitude of the CBF response were characterised using an exponential model for whole-brain and regional grey matter.The delay and rate constant for changes in R2 * were 24 s (95% CI: 21 s, 26 s) and 0.0392 s(-1) (95% CI: 0.0333 s(-1), 0.045 s(-1)), respectively, for the hypoxic response, and 12 s (95% CI: 10 s, 13 s) and 0.0921 s(-1) (95% CI: 0.0744 s(-1), 0.1098 s(-1)/) during the return to normoxia, confirming rapid changes in blood oxygenation with the end-tidal forcing system.

View Article: PubMed Central - PubMed

Affiliation: CUBRIC, School of Psychology, Cardiff University, Cardiff, UK.

Show MeSH
Related in: MedlinePlus