Background Viability assessment is a key aspect in the management of ischaemic heart disease (IHD). Hypothesis: native T1 and T2 mapping can assess myocardial viability without the use of gadolinium.

Methods 30 patients with known MI (>5yrs from MI) and 20 normal healthy controls underwent conventional 1.5T CMR to assess LV function and the presence and extent of myocardial infarction (scar transmurality) using a scale of 0–4 for the 16 AHA segment (0=no scar, 1=1–24%, 2=25–49%, 3=50–74% and 4 ≥75% scar thickness). Segments with <50% LGE was considered viable. LGE viability was compared with the corresponding native segmental T1 and T2 obtained from T1 maps (MOLLI sequence, motion corrected) and T2 maps.

Results 800 myocardial segments were analysed (320-healthy controls, 480-MI patients). The mean segmental T1 and T2 values for scar transmurality grade 0–4 were 1031±31 ms, 1070±33 ms, 1103±32 ms, 1164±58 ms, 1206±118 ms (p<0.001) and 52±4 ms, 55±4 ms, 58±5 ms, 59±8 ms, 66±9 ms (p<0.001) respectively in chronic MI. ROC analysis of 480 ?segments in chronic MI showed that for myocardial viability assessment, native T1-mapping demonstrated excellent diagnostic performance compared to LGE as the gold standard (AUC-0.94, 95%CI 0.89–0.99, p<0.0001). Native T1 mapping also had the highest diagnostic accuracy for viability assessment when compared to T2 mapping, LV wall thickness, regional wall motion abnormality. A T1 threshold of 1090ms best ?differentiated viable from non-viable segments with a sensitivity of 90% and specificity of 91%.

Conclusions Native T1 mapping can differentiate between normal, viable, and non-viable myocardium with distinctive T1 profiles in chronic MI without the need for gadolinium.