Ultrasound and fetal magnetic resonance imaging: Clinical performance in the prenatal diagnosis of orofacial clefts and mandibular abnormalities

Cleft lip, with or without cleft palate, is the most common congenital craniofacial anomaly and the second most common birth defect worldwide. Micrognathia is a rare facial malformation characterized by small, underdeveloped mandible and frequently associated with retrognathia. Second- and third-trimester prenatal ultrasound is the standard modality for screening and identification of fetal orofacial abnormalities, with a detection rate in the low-risk population ranging from 0% to 73% for all types of cleft. The prenatal ultrasonography detection can also be performed during the first trimester of pregnancy. Given the potential limitations of obstetric ultrasound for examining the fetal face, such as suboptimal fetal position, shadowing from the surrounding bones, reduce amniotic fluid around the face, interposition of fetal limbs, umbilical cord and placenta, and maternal habitus/abdominal scars, the use of adjunct imaging modalities can enhance prenatal diagnosis of craniofacial anomalies in at-risk pregnancies. Fetal magnetic resonance imaging (MRI) is a potentially useful second-line investigation for the prenatal diagnosis of orofacial malformations with a pooled sensitivity of 97%. In this review, we discuss the role of ultrasound and fetal MRI in the prenatal assessment of abnormalities of the upper lip, palate, and mandible.