BACKGROUND: Vortex formation time (VFT) had been considered a useful marker for assessing diastolic performance. the VFT assessment of diastolic function using four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has not been used in repair of tetralogy of Fallot (rTOF) patient. The aims of this study were as follows: (I) establish reference ranges for VFT measurements in healthy children and adolescents using 4D flow CMR imaging; and (II) analyze VFT parameters to assess diastole dysfunction in rTOF patients group. METHODS: We acquired the CMR data was of 62 healthy participants (aged 6–18 years; male: 40, female: 22) and 20 patients with rTOF (aged 10–13 years; male: 15, female: 5) using 4D flow and cine sequence in routine chamber view. The VFT was calculated based on comparison of different algorithms from cine measurements (VFT(volume)) and 4D flow measurements (VFT(blood)). Then, VFT measurements were compared to subject peak filling rate (PFR), age, and cardiac mass using simple linear regression and multiple regression analyses. Data were also categorized according to age for VFT and cardiac functional assessment comparisons between 3 age groups (Group 1: 6–9 years; Group 2: 10–13 years; Group 3: 14–18 years). The correlation of VFT and cardiac function parameters were analyzed in the rTOF group. RESULTS: Normal mean value of VFT(volume) and VFT(blood) were 4.25±0.92 and 3.77±1.11 in healthy children participants. The VFT(volume) was correlated with VFT(blood) (r=0.61, P
