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. Author manuscript; available in PMC: 2009 Feb 10.
Published in final edited form as: JACC Cardiovasc Imaging. 2008 Nov;1(6):772–781. doi: 10.1016/j.jcmg.2008.07.014

Figure 1. Method of Assessing Dyssynchrony With Wall Thickness Analysis by Cardiac CT.

Figure 1

(A) Left ventricular (LV) model displaying short axis slices with endocardial (white) and epicardial (red dots) casts. (B) Endocardial (red) and epicardial (green) tracing of 1 short-axis image, segmented into 6 standardized segments. Left ventricular wall thickness is depicted as the radial distance between the endocardial and epicardial contours (yellow lines). (C) Serial short axis images depicted at 10% phase increments of the cardiac cycle at 1 slice level of the mid-ventricle. Representative graphs showed the time-to-maximal LV wall thickness at 1 ventricular slice in (D) a healthy “control” with EF 66%; (E) “HF-narrow QRS patient” with nonischemic cardiomyopathy and EF 31%; (F) “HF-wide QRS patient” with ischemic cardiomyopathy, EF 33%, and LBBB; and (G) “HF-wide QRS patient” with nonischemic cardiomyopathy, EF 19%, and LBBB. The graphs displayed the wall thickness of the 6 standardized segments of the LV myocardium over 1 cardiac cycle at a single ventricular slice level. The time-to-maximal wall thickness of the 6 segments is more variable in the HF-wide QRS patients than control and HF-narrow QRS, suggesting a greater degree of dyssynchrony. A = anterior; AL = anterolateral; AS = anteroseptal; CT = computed tomography; EF = ejection fraction; HF = heart failure; I = inferior; IL = inferolateral; IS = inferoseptal; LBBB = left bundle branch block.