Quantitative assessment of left ventricular mechanical dyssynchrony using cine cardiovascular magnetic resonance imaging: Inter-study reproducibility

Figures

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  Figure 1.. Derivation of dyssynchrony indexes from CMR-FT. (a) CMR-FT was performed in basal, mid-ventricular and apical levels on standard cine images. (b) Circumferential strain systolic dyssynchrony indexes (SDI) were calculated from the standard deviation of the regional time to maximum circumferential subendocardial strain of 16 evenly distributed segments following a standard model.19 (c) Area SDI was calculated from the standard deviation of the regional time to minimum area from 16 evenly distributed segments. Grey lines indicate segments at basal levels, red lines indicate segments at mid-ventricular levels and blue lines indicate segments at apical levels. (d) Circumferential and radial uniformity ratio estimates (CURE and RURE, respectively) were calculated after plotting the circumferential and radial strain, respectively, at 48 evenly distributed locations for each time frame. The current example represents strain in one time frame. Each circle or square corresponds to one of the 48 spatial locations. The green-circled line represents perfect synchrony (corresponds URE = 1), while the red-squared line represents complete dyssynchrony (corresponds to URE = 0).

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  Figure 2.. Quantification of 4D systolic dyssynchrony indexes. 4D Beutel views were acquired from three left ventricular long-axis (two-, three- and four-chamber views) and a short-axis stack using dedicated prototype 4D LV-analysis software (TomTec, Unterschleissheim, Germany). Circles on the time volume graph correspond to regional minimum volumes. Systolic dyssychrony indexes were quantified from the standard deviation of the time to minimum volume for all 16 segments.19