Table 2. Comparison of hypercapnic CBF modulation measured using PASL and PC techniques.
| Level | PASL | PC | ||||||
|---|---|---|---|---|---|---|---|---|
| ΔCBF (%) | ΔY (%) | ΔY:ΔCBF (%/%) | ΔCMRO2 (%) | ΔCBF (%) | ΔY (%) | ΔY:ΔCBF (%/%) | ΔCMRO2 (%) | |
| Mild | 23.6±3.0 | 4.9±2.0 | 0.26±0.05 | 5.0±3.0 | 22.0±6.9 | 5.4±1.2 | 0.3±0.1 | 5.3±3.4 |
| Moderate | 53.3±3.1 | 16.9±2.1 | 0.36±0.05 | −6.8±8.0 | 30.7±8.7 | 11.0±1.7 | 0.5±0.2 | −4.3±7.0 |
| Both | N/A | N/A | 0.34±0.04 | −1.5±4.7 | N/A | N/A | 0.4±0.1 | 0.5±0.9 |
| Mild versus moderate | N/A | N/A | P=0.23 | P=0.11 | N/A | N/A | P=0.09 | P=0.15 |
CBF, cerebral blood flow; ΔCMRO2, cerebral oxidative metabolism change; N/A, not applicable; PASL, pulsed arterial-spin labeling; PC, phase contrast; PETCO2, end-tidal partial pressure of CO2.
The PASL and PC experiments used similar levels of PETCO2 perturbations, and the corresponding derived parameters, ΔY:ΔCBF and ΔCMRO2, did not differ significantly.