Figure 2
Validation and measurement of vessel-specific coronary blood flow using coronary CT angiography using TAFE formula. (A) In perfusion CT study, CBF was compared with vessel-specific MBF, a product of LV-MBF and %fractional myocardial mass (%FMM). TAFE coefficient k was calibrated. (B) CBF per myocardium (g) was calculated as the product of CBF and %FMM. Peak flow velocity was 2-fold of mean flow velocity, which is defined by dividing CBF by the average luminal area. Distal mean arterial pressure was estimated by subtracting resting whole-cycle trans-stenotic pressure gradient on the basis of the IDEAL study (1.5, 4.4, 10.8, and 29 mmHg for diameter stenosis (DS) = 0%, 1–49%, 50%–69%, and ≥70%) using mean arterial pressure, as defined by diastolic blood pressure + pulse pressure/3. Microvascular resistance calculated as the ratio of distal mean arterial pressure to the flow velocity.
