With the recent development of computational modelling and medical imaging technology, computer modeling and computer-aided procedures become more widely used in cardiac function analysis and patient-specific surgical design, replacing traditional empirical and often risky experimentation to examine the efficiency and suitability of various reconstructive cardiac procedures. In this paper, patient-specific computational models based on cardiac magnetic resonance (CMR) imaging were used to quantify right ventricle morphological and mechanical characteristics for healthy and patients with tetralogy of Fallot (TOF).  These information would form basis for further cardiac research and for potential clinical applications treat TOF patients.

Patients with repaired tetralogy of Fallot (TOF) account for the majority of cases with late onset right ventricle (RV) failure. It is a challenge to differentiate patient with better outcome after pulmonary valve replacement (PVR) from patients with worse outcome. Comparing TOF patients with healthy people may provide information to address this challenge.

Cardiac magnetic resonance (CMR) data were obtained from 16 TOF patients (8 male, median age, 42.75) and 6 healthy group (HG) volunteers (1 male, median age, 20.1). The patients with positive ejection fraction (EF) changes after PVR form the better-outcome patient group (BPG, n=5).  The patients with negative EF changes is called the worse-outcome patient group (WPG, n=11). CMR-based patient-specific computational RV/LV models were constructed to obtain RV wall thickness (WT), volumes, curvature, and mechanical stress and strain for analysis.

At begin-of-ejection, BPG stress was very close to HG stress (54.7±38.4 kPa vs. 51.2±55.7 kPa, p=0.6889) while WPG stress was much higher than HG stress (94.3±89.2 kPa vs. 51.2±55.7 kPa, p=0.0418). BPG RV volume was 43.3% higher than HG RV volume while WPG RV volume was 108.1% higher than that from HG.  BPG longitudinal curvature (L-cur) was 65.1% higher than HG L-cur, while WPG L-cur was 26.7% higher than HG L-cur.  Circumferential curvature, RV strain and wall thickness did not provide much useful information.

BPG stress was shown to be close to HG stress and stress may be used as an indicator to differentiate BPG patients from WPG patients, with further validations.