Background: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. While echocardiography and catheter angiography are established diagnostic modalities, each has its own limitations. Multidetector computed tomography (MDCT) angiography offers rapid, high-resolution, non-invasive visualisation of intra- and extracardiac structures, including coronary and pulmonary artery morphology. This study aimed to prospectively evaluate CT angiographic findings in pediatric TOF patients and correlate these with surgical and echocardiographic results.
Methods: A prospective, cross-sectional study was conducted over 1.5 years, including 30 consecutive pediatric patients with TOF. A 128-slice Siemens SOMATOM Definition AS scanner was used for imaging, with non-ECG-gated acquisitions using intravenous Iohexol as contrast. Pulmonary artery dimensions, McGoon ratio, and Nakata index were calculated. Coronary anatomy, cardiac chamber morphology, presence of PDA, major aortopulmonary collateral arteries (MAPCAs) and other details were documented. Surgical and echocardiographic findings were compared with CT results.
Results: CT showed good calibre left pulmonary artery in 70%, hypoplasia in 20%, and dilation in 10% of patients. The right pulmonary artery was normal in 80%, hypoplastic in 6.67%, and dilated in 13.33%. The most common stenosis pattern was combined subvalvular, valvular, and supravalvular narrowing. PDA (30%) and right-sided aortic arch (20%) were the most frequent associated anomalies. Coronary anomalies were present in ~26% of cases. The McGoon and Nakata indices did not show significant correlation with the type of surgery (p>0.05). Kappa analysis revealed strong agreement between CT and echocardiography, and between CT and surgery, for most parameters.
Conclusion: MDCT angiography is a highly accurate, non-invasive imaging modality for comprehensive preoperative assessment of TOF, with strong concordance to surgical and echocardiographic findings. It is particularly valuable for detecting coronary anomalies, multilevel RVOT obstruction, and extracardiac vascular anatomy. While McGoon and Nakata indices remain useful, surgical decisions also depend on broader anatomical and patient-specific considerations. Incorporating MDCT into the preoperative workflow can optimise surgical strategy and improve safety in TOF repair.
International Journal of Radiology and Diagnostic Imaging
