Tetralogy of Fallot, Transposition of the Great Arteries, and the Fontan circulation
comprise some of the most common congenital cyanotic lesions encountered in practice.
Tetralogy can be repaired initially, if the lesion is severe enough, with a systemic-to-pulmonary
shunt to augment pulmonary blood flow. Then the definitive repair closes the VSD and enlarges
the RV outflow tract. TTE is the initial imaging study of choice for Tetralogy, however, MRI and
sometimes CT complement to assess conduits and post-op pulmonary valve insufficiency. d-TGA
is characterized by ventriculoarterial discordance and initially was repaired by an atrial switch
and is now repaired by an arterial switch. CCTGA has atrioventricular in addition to
ventriculoarterial discordance and therefore does not usually necessitate surgical repair. Initial
imaging is done with TTE, but TEE, MRI, and CT are frequently required to image the baffle
from an atrial switch repair. Contrast angiography is used during percutaneous intervention to
repair baffle stenosis. The Fontan circulation is the result of a series of surgeries to repair single
ventricle anatomies. TTE is the initial imaging moda lity, but MRI is usually needed to visualize
the entire Fontan circuit. CT and TEE are sometimes used as alternatives.