Fig. 1.

TPR case example: 65-year-old male presenting after exertional collapse. a Short-axis CT-MPI image with the transmural perfusion line placed in the anterior-lateral segment (white arrow). b The transmural MBF profile. The subendocardial MBF was 58 ml/100 ml/min (purple marker) and 91 ml/100 ml/min in the subepicardium (orange marker). The TPR was 0.64 (58/91) and thus considered positive for ischaemia. c Invasive angiography showing a stenosis in the proximal LAD with an FFR of 0.69. A subtotal stenosis was directly stented in the LCX (arrowhead); as such no FFR measurement was performed. In panel a however a perfusion defect with a transmural perfusion ratio can be seen in the territory associated with the LCX. The RCA was normal with an FFR of 0.91. RCA: right coronary artery, LAD: left anterior descending artery, LCX: left circumflex artery, TPR: transmural perfusion ratio, MBF: myocardial blood flow, FFR: fractional flow reserve