Table 1.

Summary of MR-based Y_v/CMRO₂ quantification methods and their respective features.

Signal Origin	Contrast	Spatial Res.	Method	Yv Temp. Res.	Simul. CBF?
Extravascular	T2*	Voxel-wise	Calibrated BOLD51	0:03	YES
	T2′	Voxel-wise	qBOLD52	8:30	NO
Intravascular	T2	Global	TRUST53	0:24	NO
		Regional	TRU-PC54	2:50	NO
			Projection-based T255	0:15	NO
		Voxel-wise	QUIXOTIC56	27:30	NO
			VSEAN57	6:18	NO
	Susceptibility	Global	OxFlow58	0:28	YES
		Regional	Quantitative Venography131	15:42	NO
		Voxel-wise	Zhang et al.59	60:00	NO

Note: “Signal origin” is the tissue compartment in which signal used for Y_v quantification is modeled. “Contrast” is the MRI contrast mechanism used in the Y_v quantification model. “Spatial Res.” is the spatial resolution for Y_v quantification in minutes:seconds. “Method” is the name/acronym or authors associated with the published method and the most relevant citation. “Y_v Temp. Res.” is the reported approximate temporal resolution for a single Y_v measurement (ignoring any requisite planning or calibration scans). “Simul. CBF?” denotes whether the method/pulse sequence measures CBF simultaneously with Y_v. Of note, all of the above techniques allow quantification of absolute Y_v and CMRO₂, whereas calibrated BOLD techniques provide only relative changes in CMRO₂ in response to a stimulus. This limitation is removed by some recent BOLD calibration techniques employing multiple gas-mixture breathing calibration,^60,61 as discussed in the text.