Fetal Face and Neck - Abnormalities, Anatomy and Sonography

Fetal Face and Neck  Objectives:  Briefly discuss embryology  Discuss normal imaging of the fetal face and neck  Discuss abnormalities of the orbits  Review connection between face and brain anatomy  Abnormalities of the lips and palate  Discuss abnormaliti...

Fetal Face and Neck  Objectives:  Briefly discuss embryology  Discuss normal imaging of the fetal face and neck  Discuss abnormalities of the orbits  Review connection between face and brain anatomy  Abnormalities of the lips and palate  Discuss abnormalities of the fetal jaw and mouth  Discuss fetal facial and neck masses https://www.youtube.com/watch?v=iLbqzTlZ6yA Sonographic Points to Remember  Features of fetal face can be identified at end of first trimester  Profile can be well imaged with TV sonography beginning late first trimester to early second trimester  Modified coronal view best to image cleft lip and palate Copyright © 2012, 2006, 2001, 1995, 1989, 1983, 6 1978 by Mosby, an imprint of Elsevier Inc. Sonographic Points to Remember  The longitudinal view demonstrates the nasal bones, soft tissue, and mandible (useful to rule out micrognathia, anterior encephalocele, or nasal bridge defects; examine upper lip)  Transverse view shows orbital abnormalities and intraorbital distances (useful to evaluate the maxilla, mandible, and tongue) Copyright © 2012, 2006, 2001, 1995, 1989, 1983, 7 1978 by Mosby, an imprint of Elsevier Inc. Questions for the Sonographer Evaluating the Fetal Face  Are orbits normally spaced?  Are nose and nasal bridge clearly imaged; Cebocephaly (from Greek kebos, is proboscis or cebocephaly present? monkey + kephale, head) is a  Any periorbital masses apparent? developmental anomaly of the head characterized by a monkey-like  Is upper lip intact? head, with a defective small, flattened nose with a single nostril  Is tongue normal size? or absent nose and closely set eyes.Cebocephaly is part of a  Is chin abnormally small? group of defects called holoprosencephaly.  Are ears normal size and in normal position? Copyright © 2012, 2006, 2001, 1995, 1989, 1983, 8 1978 by Mosby, an imprint of Elsevier Inc.  Normal Anatomy of the Face and Neck  Face: The upper lip and nostrils may be visualized in an oblique, coronal plane. This is a good plane when you are looking for facial clefts or some types of proboscis.  Eyes  The eyes can be imaged in either a true coronal plane OR a transverse plane.  Measurements of the outer orbital distance is valuable in diagnosing hypotelorism or hypertelorism.  Inner orbital distances may also be used.  The lens of the eye is seen as a hyperechoic ring with an anechoic central portion.  The sonographer must document the presence of both eyes and assess the overall size of the eyes to exclude microphthalmia (small eyes) and anophthalmia (absent eyes). Eyes (cont.)  Masses of the orbit (periorbital) and of the eye (intraocular) may be excluded with careful scanning of the eyes.  Periorbital masses, such as lacrimal duct cysts, dermoids, and hemangiomas, have been reported. Nose  The presence of the nasal bone should be noted.  Hypoplastic and absent nasal bones are associated with Trisomy 21. The average for a “normal” nasal bone is 4.6 mm, however true determination of normalcy is based on GA  Neck  The soft tissue structures of the neck may be evaluated in both sagittal and transverse planes.  Attention to should be paid to the neck contour.  Transverse sections allow for measurement of the nuchal fold. When the nuchal fold exceeds 6 mm between 15 and 21 weeks, there is an association with trisomy 21. Facial Abnormalities  Facial Abnormalities - Abnormal Intraorbital Distance  Hypotelorism  decreased intraorbital distance. Associated with several syndromes and holoprosencephaly.  May be so severe that a single orbit is demonstrated with fused or single eye, as seen in cyclopia.  Hypertelorism  increased infraorbital distance.  Associated with anterior cephalocele and other syndromes.  How to measure:  Outer edge to outer edge of the orbit  Inner edge to inner edge of the orbit  Normal distance depends on fetal age Measuring the orbital distances Sonogram demonstrating the orbits in the coronal view. The outer orbital diameter (OOD) and inner orbital diameter (IOD) (angled arrows) are viewed. The IOD is measured from the medial border of the orbit to the opposite medial border (angled arrows). The OOD is measured from the outermost lateral border of the orbit to the opposite lateral border. Copyright © 2012, 2006, 2001, 1995, 1989, 1983, 18 1978 by Mosby, an imprint of Elsevier Inc. Hypotelorism Cyclopia Hypertelorism  Facial Abormalities - Facial Clefting  The most common congenital facial abnormality.  Statistically, 25% is cleft lip only, 25% is cleft palate only, and 50% is both.  Diagnosis relies on the presence of cleft lip to identify the abnormality in utero.  The cause is often multifactorial and it is associated with many syndromes.  Asymmetric facial clefting may occur with amniotic band syndrome. Sonographic Findings: anechoic cleft extending from nostril to lip should not be mistaken for the philtrum usually best demonstrated in a coronal section may have associated polyhydramnios difficult to detect isolated cleft palate 3-D can be helpful in evaluating cleft lip  Median Cleft Lip  Median cleft lip is a rare anomaly consisting of a midline vertical cleft through the upper lip.  It can also involve the premaxillary bone, the nasal septum, and the central nervous system.  May or may not have cleft palate.  Related to differentiation of the forebrain and is often associated with other midline defects of the face such as holoprosencephaly.  Sonographic Findings:  Similar to cleft lip/palate  search for other facial and intracranial abnormalities. Median Cleft lip A. Unilateral Cleft B. Bilateral Cleft C. Median Cleft Lip Tongue – Macroglossia  Tongue protrusion may suggest macroglossia, a condition found in Beckwith-Wiedemann syndrome  Organomegaly also feature of this syndrome  Some glycogen storage diseases may also exhibit macroglossia and organomegaly.  Abnormal Profile - Micrognathia  Abnormally small jaw  associated with several syndromes and chromosomal abnormalities, specifically, Trisomy 18. Micgrognathia  Frontal Bossing  prominent forehead due to absent nasal bridge.  Associated with skeletal dysplasia and other syndromes.  Masses of the Face - Epignathis  Rare  pharyngeal teratoma that protrudes from the fetal mouth  Sonographic findings:  complex, cystic and solid mass that may hyperextend the neck  Associated with polyhydramnios due to fetal inability to swallow  Proboscis  a rare congenital anomaly where an anterior appendage like structure is seen projecting from the midline fetal face/forehead.  Depending on the exact location, this has further been classified into various sub types (e.g. inter-orbital proboscis).  Proboscis  The presence of a proboscis can be associated with several anomalies which include:  trisomy 13  holoprosencephaly  cebocephaly  ethmocephaly  cyclopia: often below the level of the proboscis  A proboscis is best seen on a longitudinal facial profile view as a snout like protrusion from the face/forehead. Abnormalities of the Neck  Cystic Hygroma  Benign, developmental abnormality of lymphatic system origin  single or multiple cystic areas form around the neck  Associated with chromosomal abnormalities such as Turner’s and Down Syndrome.  Large Hygromas are often associated with fetal hydrops.  Sonographic findings:  thin walled, multiseptated mass at posterior aspect of neck  may see a nuchal ligament extending posteriorly  associated with hydrops - so you may see fetal ascites, ansarca, pleural effusion  may mimic cervical teratoma, encephalocele, cervical meningomyelocele Transverse plane  Cervical Teratoma  May occur anywhere around the neck.  Complex/cystic/solid mass near the fetal neck.  May be mistaken for a cystic hygroma or pharyngeal teratoma. Nuchal Thickening  Increased soft tissue thickness at the posterior aspect of the neck.  Associated with trisomy 21.  obtain the image of the oblique/axial cross section of the head that shows the CSP, cerebellum and cisterna magna.  Measurement of greater than 6 mm is considered abnormal when measured between 15 and 21 weeks.  Note: Fetal head must not be hyperextended.