The manual segmentation was performed by a group of experienced investigators from the National Heart Centre Singapore (NHCS), consisting of CMR consultants, well-trained clinical research fellows and engineers, using a standardized protocol described in detail in a separate publication (14 (link)). Two operators with over five years' experience (LTT and CWLC) then checked the contouring quality to select the studies deemed for further analysis.
Specifically, left ventricle (LV) endocardial and epicardial borders and the right ventricle (RV) endocardial borders were manually traced in SAX slices at end-diastole (ED) and end-systole (ES) time frames using the cvi42 post-processing software (version 5.1.1, Circle Cardiovascular Imaging Inc., Calgary, Alberta, Canada). ED and ES phases were defined, respectively, as the image with the largest and smallest LV blood volume at visual inspection. The manual contours and the corresponding images were saved for later processing.
Free full text: Click here