Delayed entry and exit from the microvasculature. There is the ground glass appearance (“blush”) or opacification of the myocardium in the distribution of the artery that is strongly persistent during the washout phase (i.e. dye is strongly persistent after 3 cardiac cycles and either does not or minimally diminishes in intensity during washout).
The 3 cardiac cycles are determined from the point when dye touches either none or only one of the arterial borders (TIMI Frame 0). Strongly persistent blush at its maximum intensity is as intense/bright or more intense/bright as the fully-opacified surrounding collaterals.
Intensity Range:<unk>  - 3
TIMI myocardial perfusion grade 2
TIMI myocardial perfusion grade 0.5
TIMI myocardial perfusion grade 3
TIMI myocardial perfusion grade 1
TIMI myocardial perfusion grade 0
TIMI flow grade 3
TIMI thrombus grade 3
TIMI flow grade 4