Figure 6.

Effect of volitional apnea on brain vascular-metabolic parameters: a) Expanded parametric maps of flow velocity and phase difference Δφ (for SvO₂ measurement) obtained with a single-site OxFlow sequence acquiring data at the same anatomic site (SSS) at 3s temporal resolution, showing enhanced flow and increased SvO₂ (manifested by reduced phase difference) during apnea. b) Fractional changes in parameter values normalized to average baseline. Error bars indicate ±1 SD, gray area the apnea period. Values in time-course plot were averaged across the three repeated blocks of the paradigm. Bracketed sections ‘Base’ and ‘EA’ indicate the data used for computing average baseline values and end-apnea values (reproduced from (55), with permission).