Assistant Professor, Tehran University of Medical Science (TUMS)
Computed tomography (CT) angiography with high-quality multiplanar reformatted images plays an important role in the assesment of patients with congenital heart disease (CHD).being familiar with congenital heart diseases and systematic and a step-by-step approach are necessary for understanding the normal anatomy and typical pathologic conditions in CHD patients. This approach consists of evaluation of: 1-visceroatrial situs 2-the ventricular loop 3-Origin and Position of the Great Vessels 4-the relationships between the atria and ventricles and the ventricles and great vessels 5-the cardiac chambers, septa, outflow tract and PVs.
The type of situs is determined by the relationship between the atria and the adjacent organs, there are three types of situs: solitus, inversus, and ambigus. The aorta and MPA are classified according to their position and relation at the level of the aortic and pulmonic valves. In the normal position of the great arteries, the aorta is posterior to and right side of the MPA. In situs inversus the aortic root is located posterior but left side of MPA. if the aorta locates anterior to MPA , it is considered transposition and if be parallel ,it is considered malposition.
The Van Praagh notation is a three-part series of letters, with each part corresponding to a segment of the cardiac anatomy: the atria, ventricles, and great vessels. The three parts are separated by commas The first letter relates to the visceroatrial situs; the second, the left- or rightward orientation of the ventricular loop; and the third, the position and relation of the great vessels. Then the atrio-ventricular and ventricuolo-arterial connection should be assessed which could be concordant or discordant.
At the level of the heart, the presence, size, and location of atrial and ventricular septal defects and the size of the ventricles and atrias should be mentioned.The aorta and pulmonary artery also should be carefully examined for evidence of any abnormality. Finally any associated lung, thorax and vertebral abnormality should be evaluated.