慢性心筋梗塞における心臓磁気共鳴特徴追跡ひずみによる遠隔心室機能不全の評価

To quantify regional LV deformation parameters in subjects with chronic myocardial infarction (MI) by the combination of CMR feature tracking (CMR-FT) and LGE images to assess segmental myocardial function in remote myocardium and to evaluate their relationships with infarct size and post-infarction LV global function.

CMR-images (SSFP cine and LGE) were acquired from 34 chronic MI patients and 32 healthy volunteers included in this retrospective study. LV ejection fraction (LVEF), infarct size (IS), CMR-FT regional circumferential, radial and longitudinal strain (CS, RS, LS), time-to-peak strain (TTP-CS, TTP-RS, TTP-LS) and rotation were measured.

CS, RS and LS were greater for remote, adjacent and border zones than for infarct areas (p<0.01); TTP-CS, TTP-RS and TTP-LS values were shorter for remote and border zones than for infarct areas (p<0.05). Maximum apical rotation was found at the border zone (p<0.05). Remote CS, RS and LS in MI were significantly lower than in healthy subjects (p<0.01). Remote CS and LS correlated with IS (CS: r=0.75, LS: r=0.82, p<0.0001) and LVEF (CS: r=-0.87, LS: r=-0.83, p<0.001). In ROC analysis for the detection of contractile dysfunction in RM, IS and LVEF performed best with AUCs of 0.98 and 0.94, showing cut-off values of 17 % and 54 %, respectively.

Quantitative assessment of LV strain and rotation provides deformation characteristics of infarct, border and remote areas in patients with chronic MI, relating contractile dysfunction in remote areas to the extent of the infarcted region, which could offer useful clinical insights into the LV remodeling process.