Ventricular 4D flow components and energy in Tetralogy of Fallot: 4D flow MRI study

Liang Zhong
National Heart Center Singapore


Survivors of tetralogy of Fallot (TOF) constitute a large and growing population of patients. Although post-surgical outcome is generally favorable, as these patients move into adulthood, late morbidity is becoming more prevalent. Recent evidence suggests that adverse long-term post-surgical outcome is related to chronic pulmonary regurgitation (PR) and RV dilation. This process, also called RV remodeling, adversely affects ventricular function and may lead to development of heart failure. Repeat surgery with pulmonary valve replacement (PVR) may be necessary to preempt RV functional deterioration and malignant ventricular arrhythmias. Therefore, understanding and quantifying RV remodeling in repaired TOF patients is important for patient management and therapy planning.

Cardiac MR imaging (MRI) is considered as “best” imaging choice for assessing the remodeled RV without exposing the patient to ionizing radiation. 4D flow CMR is emerging approach to gain additional insight of RV remodeling and dysfunction [1,2]. In this talk, we will discuss the predominantly qualitative measures of RV remodeling indexes including two-dimensional RV diameter, volumes and ejection fraction, CMR feature tracking [3], in particular 4D flow component and kinetic energy indexes from 4D flow CMR in rTOF. All these would satisfactorily express the full range of quantitative information related to the remodeling process.


  1. Zhong L et al. Intracardiac 4D flow MRI in congenital heart disease: recommendations on behalf of the ISMRM flow & motion study group. J Magn Reson Imaging 2019;50:677-681.
  2. Zhao XD, et al, Zhong L. Insight of right ventricular dysfunction and impaired efficiency via 4D flow CMR in repaired tetralogy of Fallot. ISMRM 2021.
  3. Ouyang RZ et al Zhong L. Detection of persistent systolic and diastolic abnormalities in asymptomatic pediatric repaired tetralogy of Fallot patients with preserved ejection fraction: a CMR feature tracking study. Eur Radiol 2021.