Three- and four-dimensional ultrasound in the diagnosis of fetal tetralogy of fallot with absent pulmonary valve and microdeletion 22q11.

Tetralogy of Fallot (TOF) with concomitant absent pulmonary valve syndrome (APVS) constitutes a rare prenatal condition characterized by rudimentary cusps of the pulmonary valve, pulmonary regurgitation, and a variable degree of dilatation of the main and branch pulmonary arteries. Although early prenatal diagnosis of this complex malformation is feasible, the antenatal course of affected fetuses clearly depends on the presence of associated structural (absence of the ductus venosus) and chromosomal anomalies (microdeletion 22q11, DiGeorge syndrome). Postnatally, the outcome is closely related to the degree of airway obstruction and subsequent bronchomalacia. We describe the beneficial contribution of three- and four-dimensional ultrasound in establishing the diagnosis of TOF-APVS in a fetus at age 22 gestational weeks.