Native left ventricular myocardial T1 spatial heterogeneity in non-ischemic dilated cardiomyopathy
Journal of Cardiovascular Magnetic Resonance volume 18, Article number: Q41 (2016)
Myocardial fibrosis is involved in the pathology of non-ischemic dilated cardiomyopathy (NICM). Recently, the application of native (non-contrast) myocardial T1 measurement has been proposed as an imaging biomarker of cardiac remodeling. However, spatial heterogeneity in T1 measurements has been observed across different segments and slices. Furthermore, T1 values measured with current T1 mapping sequences are influenced by myocardial T2 values. The objective of this study was to 1) assess the spatial heterogeneity of T1 measurements across different segments and slices in healthy subjects and patients, and 2) determine the association of native T1 with myocardial structure and function.
We prospectively studied 39 NICM patients (LVEF≤50% without evidence of prior infarction by CMR) and 30 subjects with normal LV systolic function without known cardiovascular disease. CMR was performed using a 1.5-T MRI scanner (Philips Achieva). Native T1 mapping was performed using slice-interleaved T1 mapping sequence (STONE) . T2 mapping was performed using slice-interleaved T2 mapping . Voxel-wise T1 and T2 were estimated using a 2-parameter and 3-parameter model . All images were corrected for motion . T1, T2, and extra-cellular volume (ECV) measurements were measured using a 16 segments AHA model across the base, mid, and apical LV.
NICM participants (57 ± 15 years) were predominantly male (74%). By design, all had a reduced LV ejection fraction (mean LVEF 34 ± 10%). Figure 1 shows native T1, T2, and ECV in two patients with a NICM. Parametric maps to the right in each panel demonstrate full ventricular coverage. The regional distribution of native myocardial T1 was similar in patients with and without NICM[RN1], as shown in Figure 2. Relative to subjects without NICM, subjects with NICM had a higher native T1 (1131 ± 51 vs. 1070 ± 28 msec; p < 0.0001), a higher ECV (0.28 ± 0.04 vs. 0.25 ± 0.02, P = 0.001) and a longer myocardial T2 (52 ± 8 vs. 47 ± 5 msec; P = 0.01). After multivariable adjustment, a lower global native T1 time was associated with a higher LVEF (b = -0.59, P = 0.0003), higher right ventricular ejection fraction (b = -0.47, P = 0.006), and lower left atrial volume index (b = 0.51, P = 0.001).
In NICM, native myocardial T1 is elevated in a homogeneous manner, suggesting a global (not regional) abnormality in myocardial tissue composition. This low variability is similar between healthy and NICM patients across different segments. For subjects with NICM, native T1 is associated with biventricular systolic function and left atrial volume, and may represent a non-contrast marker of tissue remodeling in this cohort.
Weingartner : MRM. 2015
Basha : MRM. 2015
Akcakaya : MRM. 2015
Roujol : JCMR. 2015
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Kashem, A., Shah, R.V., Kato, S. et al. Native left ventricular myocardial T1 spatial heterogeneity in non-ischemic dilated cardiomyopathy. J Cardiovasc Magn Reson 18 (Suppl 1), Q41 (2016). https://doi.org/10.1186/1532-429X-18-S1-Q41