TY - JOUR
T1 - Assessment of Myocardial Microstructural Dynamics by In Vivo Diffusion Tensor Cardiac Magnetic Resonance
AU - Nielles-Vallespin, Sonia
AU - Khalique, Zohya
AU - Ferreira, Pedro F.
AU - de Silva, Ranil
AU - Scott, Andrew D.
AU - Kilner, Philip
AU - McGill, Laura Ann
AU - Giannakidis, Archontis
AU - Gatehouse, Peter D.
AU - Ennis, Daniel
AU - Aliotta, Eric
AU - Al-Khalil, Majid
AU - Kellman, Peter
AU - Mazilu, Dumitru
AU - Balaban, Robert S.
AU - Firmin, David N.
AU - Arai, Andrew E.
AU - Pennell, Dudley J.
N1 - Publisher Copyright:
© 2017
PY - 2017/2/14
Y1 - 2017/2/14
N2 - Background Cardiomyocytes are organized in microstructures termed sheetlets that reorientate during left ventricular thickening. Diffusion tensor cardiac magnetic resonance (DT-CMR) may enable noninvasive interrogation of in vivo cardiac microstructural dynamics. Dilated cardiomyopathy (DCM) is a condition of abnormal myocardium with unknown sheetlet function. Objectives This study sought to validate in vivo DT-CMR measures of cardiac microstructure against histology, characterize microstructural dynamics during left ventricular wall thickening, and apply the technique in hypertrophic cardiomyopathy (HCM) and DCM. Methods In vivo DT-CMR was acquired throughout the cardiac cycle in healthy swine, followed by in situ and ex vivo DT-CMR, then validated against histology. In vivo DT-CMR was performed in 19 control subjects, 19 DCM, and 13 HCM patients. Results In swine, a DT-CMR index of sheetlet reorientation (E2A) changed substantially (E2A mobility ∼46°). E2A changes correlated with wall thickness changes (in vivo r2 = 0.75; in situ r2 = 0.89), were consistently observed under all experimental conditions, and accorded closely with histological analyses in both relaxed and contracted states. The potential contribution of cyclical strain effects to in vivo E2A was ∼17%. In healthy human control subjects, E2A increased from diastole (18°) to systole (65° p < 0.001; E2A mobility = 45°). HCM patients showed significantly greater E2A in diastole than control subjects did (48° p < 0.001) with impaired E2A mobility (23° p < 0.001). In DCM, E2A was similar to control subjects in diastole, but systolic values were markedly lower (40° p < 0.001) with impaired E2A mobility (20° p < 0.001). Conclusions Myocardial microstructure dynamics can be characterized by in vivo DT-CMR. Sheetlet function was abnormal in DCM with altered systolic conformation and reduced mobility, contrasting with HCM, which showed reduced mobility with altered diastolic conformation. These novel insights significantly improve understanding of contractile dysfunction at a level of noninvasive interrogation not previously available in humans.
AB - Background Cardiomyocytes are organized in microstructures termed sheetlets that reorientate during left ventricular thickening. Diffusion tensor cardiac magnetic resonance (DT-CMR) may enable noninvasive interrogation of in vivo cardiac microstructural dynamics. Dilated cardiomyopathy (DCM) is a condition of abnormal myocardium with unknown sheetlet function. Objectives This study sought to validate in vivo DT-CMR measures of cardiac microstructure against histology, characterize microstructural dynamics during left ventricular wall thickening, and apply the technique in hypertrophic cardiomyopathy (HCM) and DCM. Methods In vivo DT-CMR was acquired throughout the cardiac cycle in healthy swine, followed by in situ and ex vivo DT-CMR, then validated against histology. In vivo DT-CMR was performed in 19 control subjects, 19 DCM, and 13 HCM patients. Results In swine, a DT-CMR index of sheetlet reorientation (E2A) changed substantially (E2A mobility ∼46°). E2A changes correlated with wall thickness changes (in vivo r2 = 0.75; in situ r2 = 0.89), were consistently observed under all experimental conditions, and accorded closely with histological analyses in both relaxed and contracted states. The potential contribution of cyclical strain effects to in vivo E2A was ∼17%. In healthy human control subjects, E2A increased from diastole (18°) to systole (65° p < 0.001; E2A mobility = 45°). HCM patients showed significantly greater E2A in diastole than control subjects did (48° p < 0.001) with impaired E2A mobility (23° p < 0.001). In DCM, E2A was similar to control subjects in diastole, but systolic values were markedly lower (40° p < 0.001) with impaired E2A mobility (20° p < 0.001). Conclusions Myocardial microstructure dynamics can be characterized by in vivo DT-CMR. Sheetlet function was abnormal in DCM with altered systolic conformation and reduced mobility, contrasting with HCM, which showed reduced mobility with altered diastolic conformation. These novel insights significantly improve understanding of contractile dysfunction at a level of noninvasive interrogation not previously available in humans.
KW - dilated cardiomyopathy
KW - helical structure
KW - hypertrophic cardiomyopathy
KW - laminar structure
KW - left ventricle
KW - sheetlet structure
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U2 - 10.1016/j.jacc.2016.11.051
DO - 10.1016/j.jacc.2016.11.051
M3 - Article
C2 - 28183509
AN - SCOPUS:85011615033
SN - 0735-1097
VL - 69
SP - 661
EP - 676
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 6
ER -