Table 2.

Different levels of spatial resolution considered for MBF calculation.

Resolution level	Notation	Total number of volumes	Order of magnitude	Description
Whole myocardium	${\text{MBF}}_{\text{myo}}$	1	$100\text{mL}$	Organ scale. ${\text{MBF}}_{\text{myo}}$ is calculated according to Eq. 11, where the entire myocardial volume is considered as the perfusion volume.
Main coronary arteries	${\text{MBF}}_{\text{trees}}$	3	$35\text{mL}$	Each perfusion volume corresponds to the perfusion territory of each main coronary artery (RCA, LAD, LCX).
AHA segments	${\text{MBF}}_{\text{AHA}}$	17	$6\text{mL}$	Perfusion volumes correspond to AHA segments detailed in Ref. 6
Voxels	${\text{MBF}}_{\text{voxels}}$	$\approx$1,000,000	${10}^{-4}\text{mL}$	High resolution from cCTA, for characterization of MBF at the local level.