Non-contrast quantitative T1-mapping indicates that salvaged myocardium develops edema during coronary occlusion, whereas infarction exhibits evidence of additional reperfusion injury

Methods Dogs (n=9) underwent coronary occlusion and reperfusion to delineate the time course of development of changes in non-contrast T1 abnormalities. T1 was quantified by 1.5T CMR (Siemens) using a Modified LookLocker Inversion Recovery (MOLLI) sequence. T2prepared SSFP (T2p) and LGE images were acquired at the end of the experiment to define 1) Infarction [LGE positive], 2) Salvaged myocardium [T2p positive and LGE negative] and 3) Remote [T2p and LGE negative]. Myocardium which ultimately ended being classified into these three tissue types was identified, and T1 was quantified over time starting from baseline prior to occlusion. Results See Figure 1. During occlusion, T1 increased in tissue which ultimately became Infarction or Salvaged (p<0.01 for both), and to a greater extent in tissue which ultimately became Infarction compared to Salvaged (p=0.03). Within 30 minutes of reperfusion, T1 of Infarction increased further (p=0.001), whereas T1 of Salvaged myocardium remained unchanged after reperfusion (p=0.73).