Table 2.

Summary of CMRATPase results in healthy human brain directly measured by 31P-MT method and indirectly estimated from PET or 13C MRS measurements.

Study	Method	Brain Region	Measured Parameter	CMRATPase (μmol/g/min)
Present Study	31P-MT CSI	Global	CMRATPase	6.4
Fox et al., 1988	15O PET	Global	CMRO2a	7.5
Ito et al., 2004	15O PET	Global	CMRO2a	6.8
Fox et al., 1988	18F PET	Global	CMRglcb	10.2
Lei et al., 2003	31P-MT MRS	Visual	CMRATPase	12.1 (8.3)d
Du et al., 2007	31P-MT MRS	Visual	CMRATPase	8.8
Fox et al., 1988	15O PET	Visual	CMRO2a	8.5
Fox et al., 1988	18F PET	Visual	CMRglcb	11.5
Shen et al., 1999	13C MRS	Occipital-Parietal	VTCAc	10.6
Gruetter et al., 2001	13C MRS	Occipital-Parietal	VTCAc	8.6
Boumezbeur et al., 2010	13C MRS	Occipital-Parietal	Vtcac	8.9

^aP/O ratio of 2.5 is used to estimate CMR_ATPase values from CMRO₂ (Hinkle PC, 2005).

^bOGI value of 5.5 and P/O ratio of 2.5 are used to estimate CMR_ATPase values from the CMR_glc (Vaishnavi et al., 2010; Shulman et al., 2001).

^cCMR_glc=0.5V_TCA, OGI=5.5 and P/O=2.5 are used to estimate CMR_ATPase values from the V_TCA (Rothman et al., 2011).

^dCMR_ATPase value in parentheses is calculated based on intracellular Pi concentration of 0.9 mM (Du et al., 2007).