Figure 22

Tissue tracking of the ventricular myocardium (LV = left panel; RV = right panel) in a patient with repaired TOF. Analysis of circumferential strain is performed in the ventricular short-axis plane using a commercial tissue tracking software package and custom-built filters to modify the DICOM headers of the CMR datasets to allow them to be analyzed by the software package. The myocardium is divided into 6 segments and circumferential strain (Y-axis;%) versus time (X-axis; milliseconds) is plotted for each segment. The time difference to peak circumferential strain--a measure of ventricular synchrony--measured 83 ms in the LV and 389 ms in the RV, reflecting RV dyssynchrony.