Morphological study of pulmonary artery of Tetralogy of Fallot based on tortuosity analysis.

Tetralogy of Fallot (TOF) is one of the commonest cyanotic congenital heart diseases, characterized by the highly variable anatomy of pulmonary artery (PA), location and degree of obstruction. Subtle alterations in the geometry of PAs would cause changes of pulmonary hemodynamics, which are closely associated with the outcome of TOF patients. Hence, it is critical to understand the geometric characteristics of PA in TOF patients. This study was conducted to explored the differences of tortuosity of PAs between TOF patients and children with normal PAs. And there were twenty TOF patients and ten individuals with normal PA. The three-dimensional geometries of PAs were constructed based on preoperative computed tomography data. The tortuosity of pulmonary arteries were quantitatively measured and statistically analyzed. It was found that there were no obvious differences in the tortuosity of right pulmonary artery (RPA) between TOF and control groups (1.07 ± 0.044 vs. 1.07 ± 0.029, P = 0.977). Nevertheless, the tortuosity of main pulmonary artery (MPA) (1.07 ± 0.012 vs. 1.11 ± 0.038, P < 0.0001) and the tortuosity of left pulmonary artery (LPA) (1.10±0.022 vs. 1.18±0.070, P = 0.001) were relatively higher in the TOF group compared with the control group. The positive correlation was found between the tortuosity of MPA and the tortuosity of LPA (r=0.618, P < 0.0001). The area under the curve (AUC) of the MPA tortuosity and the LPA tortuosity was 0.945 and 0.935, respectively. They exhibit both high sensitivity and specificity in the diagnosis of TOF. The cutoff value of the MPA tortuosity was 1.092, and that of the LPA tortuosity was 1.117. It revealed that increased tortuosity of MPA and LPA in TOF patients compared with those of normal subjects, which might provide guidance for the diagnostic evaluation and prognostic prediction of TOF patients.