3D ultrasound and the fetal palate. Re: Qualitative evaluation of Crystal Vue rendering technology in assessment of fetal lip and palate

Understanding the distinction between cleft lip and cleft palate: a critical step for successful prenatal detection

PURPOSE OF REVIEW

Orofacial clefts (OCs) are among the most common congenital anomalies, however, prenatal detection of cleft palate without cleft lip (CP) remains low. CP is associated with a higher risk of associated structural anomalies, recurrence risk and genetic aberrations. There is opportunity to optimize prenatal diagnosis, counseling and diagnostic genetic testing for OCs.

RECENT FINDINGS

Improving prenatal diagnosis of CP requires understanding that embryologically, the secondary palate develops from the 6th to the 10th week and fuses with the primary palate by the 12th week. Multiple first, second and third trimester 2D ultrasonographic markers for OCs have been described including the maxillary gap, frontal space, maxilla-nasion-mandible angle, retronasal triangle, palatino-maxillary diameter, equal sign, nonvisualization or gap in the soft to hard palate interface and loss of the superimposed line. We discuss the technique, evidence and limitations of each.

SUMMARY

Prenatal detection of OC can be optimized by employing 2D sonographic markers. Prenatal detection of CP may be improved by recognizing its high association with retrognathia/micrognathia.

Clinical outcomes of prenatal diagnosis of the fetal micrognathia: A case report

RATIONALE

Micrognathia is a subtle facial malformation characterized by a small mandible and receding chin. Fetal micrognathia is often associated with chromosomal abnormalities, skeletal dysplasia, and various syndromes. Once it is dignosised, detailed fetal malformation screening and chromosome examination should be carried out.

PATIENT CONCERN

One pregnant woman with suspicion of fetal micrognathia was referred from her local hospital to our hospital for detailed fetal malformation screening and fetal echocardiography. Examination of the fetus was performed using a two-dimensional and three-dimensional ultrasound probe in multiple planes. The fetus showed micrognathia without glossoptosis with features of the inferior facial angle (IFA) ≤50° and his tongue reached anterior mandibular border box during normal movement.

DIAGNOSES

The fetus was diagnosed as isolated micrognathia prenatally without multisystem abnormalities.

INTERVENTIONS

Amniocentesis was performed and the fetus was found to carry 46XN with 6q14.1 duplication, the significance of which was unclear.

OUTCOMES

The fetus was labored through vagina at 38 weeks gestation. A small soft cleft palate was diagnosed after delivery.

LESSONS

This case suggests that once prenatal diagnosis of the fetal micrognathia has been made, we should carefully examine the presence of fetus's multisystem developmental abnormalities and due consideration should be given for associated soft cleft palate.

Ultrasound imaging of the fetal secondary palate: Methodological description of a two-dimensional approach and a case series

OBJECTIVE

The study aims to describe our two-dimensional (2D) ultrasound approach to visualize the fetal secondary palate and plot its growth curve and to describe and demonstrate its clinical implementation.

METHODS

This is a two parts retrospective study. First, we measured the antero-posterior length of the bony secondary palate, from the soft to hard palate interface (SHPI) line to the alveolar ridge, blindly by two operators during routine scans of low-risk fetuses, and plot a longitudinal growth curve. In the second part, we describe four cases of prenatal diagnosis of secondary palate cleft.

RESULTS

Sixty-eight fetuses were included: 14 to 15 weeks (n = 20), 21 to 24 weeks (n = 32), and 29 to 35 weeks (n = 16). The bony secondary palate elongates along gestation from a mean of 5.3 mm (+/-0.46 mm) at 14 to 15 weeks to 15.9 mm (+/-1.7 mm) at 29 to 35 weeks. We found high intraobserver and interobserver correlation between measurements. All four cases diagnosed by this approach were confirmed postnatally.

CONCLUSIONS

The SHPI, representing the normally developed secondary bony palate, can be imaged in the fetus by direct 2D ultrasound as early as 14 weeks. A gap within or nonvisualization of the SHPI is highly suggestive for a secondary palate cleft.

Accurate diagnosis of fetal cleft lip/palate by typical signs of magnetic resonance imaging

OBJECTIVE

This study aims to evaluate the accuracy of magnetic resonance imaging (MRI) in diagnosing orofacial clefts and proposes specific signs for determining the type of cleft.

METHODS

Pregnant women in whom fetal facial malformations are suspected by ultrasonography (US) underwent 1.5 T MRI. The accuracy of the prenatal US and MRI diagnosis was compared with the postnatal findings.

RESULTS

A total of 71 fetuses were included in the final analysis, which comprised of 35 cases of isolated cleft lip, six cases of cleft lip and alveolus, 21 cases of cleft lip and palate, four cases of isolated cleft palate, and five normal fetuses. MRI was more sensitive than US (MRI 100%, US 77.5%; Fisher's exact test: MRI vs US P=0.000). The accuracy of MRI for all types was 100%. Specific signs (Inverted T, L/anti-L, U, and "Notch" signs) were proposed, indicating the normal hard, unilateral cleft, bilateral cleft, and cleft soft palates, respectively, which can facilitate the identification of different types of cleft palates.

CONCLUSION

MRI can accurately diagnose the type of cleft based on typical signs, which can serve as a definite diagnostic modality and an effective supplement of US.