Purpose: We sought to use non-contrast-enhanced T1 mapping to determine the native T1 values required to identify myocardial fibrosis in patients with dilated cardiomyopathy (DCM).
Methods: A total of 25 patients with DCM and 15 healthy controls were enrolled. All subjects underwent T1 mapping using modified look-locker inversion recovery, and the patients underwent late gadolinium-enhancement (LGE) imaging. Basal and mid-ventricular levels were divided into eight segments and the T1 value was measured in each segment. The T1 values of septal segments with LGE were compared with those of the septal segments without LGE, the minimum T1 value of each patient, and the T1 values of the normal septal myocardium.
Results: Late gadolinium-enhancement was present in 12 septal segments (24.0%) from 10 patients (40.0%). T1 values were significantly higher in septal segments with LGE than in those without (1373.7 vs. 1288.0 ms; P = 0.035) or in normal septal myocardium (1209.1 ms; P < 0.01). A receiver operating characteristic analysis revealed the appropriate cutoff value of 1349.4 ms for identifying LGE with a sensitivity of 75% and specificity of 92.1%. When the minimum T1 value + 1.2 standard deviation (SD) was used as the threshold, the sensitivity was 75% and specificity was 89.5%.
Conclusion: Non-contrast-enhanced T1 mapping can be used for assessment of myocardial fibrosis associated with DCM by using the appropriate threshold.
Keywords: T1 mapping; dilated cardiomyopathy; late gadolinium enhancement; myocardial fibrosis.