[Table/Fig-2]:

Tetralogy of Fallot.

TOF
Components	VSD (usually perimembranous)	RVOT obstruction (at infundibular, pulmonary valvular or combination)	RVH	Overriding of aorta
Incidence [13]	1-3 cases per 1000 live births. Most common cyanotic CHD. Arises from single gene defect involving TBX1 gene (TBX1 gene encodes for a transcriptional factor integral to development of cardiac outflow tracts)
Association [13]	Right aortic arch (25%). Abnormal coronary arteries (5%) LAD arising from RCA with prepulmonic course being most common. Complete AVSD (2%) Persistent left SVC
Syndromes	CHARGE syndrome Di George syndrome Shprintzen (velo-cardio-facial) syndrome
Imaging features Plain	Boot shaped heart (cor en Sabot)= concave MPA segment with an upturned apex	Pulmonary oligemia	Thymic atrophy	Right aortic arch
Imaging features specific	Echo defines all components of TOF MRI useful in post-surgical follow-up for RV volume assessment, pulmonary regurgitation quantification and to rule out residual VSD CT evaluation of pulmonary arteries, collaterals and coronary arteries * McGoon Ratio and Nakata Index are used for quantification of degree of PA hypoplasia
Management [13]	Palliative procedures: • Modified Blalock-Taussig shunt most preferred; placement of Gore-Tex interposition graft between subclavian artery and ipsilateral pulmonary artery Definitive surgery: Total ICR (intracardiac repair) VSD patch closure + widening of RVOT (infundibular tissue resection) + pulmonary valvotomy Note: Presence of coronary anomalies (esp. LAD from RCA with RVOT crossing) is a contraindication for primary repair.