Fig. 2.

Representative end-tidal CO₂ (etCO₂) timeseries data across the duration of pseudo-continuous arterial spin labeling (pCASL) scans for 0.1Hz paced breathing (top) and breath hold (bottom) conditions. Raw capnography recordings of etCO₂ are shown as gray traces. Extracted etCO₂ values are shown in bold colored lines. Top (blue): EtCO₂ levels are gradually decreasing during 0.1Hz paced breathing (hypocapnia). Bottom (red): Dashed lines indicate breath holds. The exhale immediately following each breath hold shows an increase in etCO₂ (hypercapnia).