In this study, we developed an automatic pipeline and segmentations of left ventricle walls for mapping myocardial extracellular volume fraction (ECV) and calculating global ECV values. The system combined with user-friendly web-based user interface was packaged into a software container. We used this system to analyze myocardial T1 images obtained from subjects with tetralogy of Fallot (TOF). The ECV values of the TOF data sets were significantly higher than those of the normal subjects. This automatic pipeline could be a practical tool for clinical evaluations of myocardial fibrosis with MR MOLLI T1 images.