Sonographic assessment of normal fetal palate using three-dimensional imaging: a new technique

Ultrasonic mapping of midpalatal suture - An ex-vivo study

OBJECTIVE

Rapid maxillary expansion is a common orthodontic procedure to correct maxillary constriction. Assessing the midpalatal suture (MPS) expansion plays a crucial role in treatment planning to determine its effectiveness. The objectives of this preliminary investigation are to demonstrate a proof of concept that the palatal bone underlying the rugae can be clearly imaged by ultrasound (US) and the reconstructed axial view of the US image accurately maps the MPS patency.

METHODS

An ex-vivo US scanning was conducted on the upper jawbones of two piglet's carcasses before and after the creation of bone defects, which simulated the suture opening. The planar images were processed to enhance bone intensity distribution before being orderly stacked to fuse into a volume. Graph-cut segmentation was applied to delineate the palatal bone to generate a bone volume. The accuracy of the reconstructed bone volume and the suture opening was validated by the micro-computed tomography (µCT) data used as the ground truth and compared with cone beam computed tomography (CBCT) data as the clinical standard. Also included in the comparison is the rugae thickness. Correlation and Bland-Altman plots were used to test the agreement between the two methods: US versus µCT/CBCT.

RESULTS

The reconstruction of the US palatal bone volumes was accurate based on surface topography comparison with a mean error of 0.19 mm for pre-defect and 0.15 mm and 0.09 mm for post-defect models of the two samples, respectively when compared with µCT volumes. A strong correlation (R2 ≥ 0.99) in measuring MPS expansion was found between US and µCT/CBCT with MADs of less than 0.05 mm, 0.11 mm and 0.23 mm for US, µCT and CBCT, respectively.

CONCLUSIONS

It was possible to axially image the MPS opening and rugae thickness accurately using high-frequency ultrasound.

CLINICAL SIGNIFICANCE

This study introduces an ionizing radiation-free, low-cost, and portable technique to accurately image a difficult part of oral cavity anatomy. The advantages of conceivable visualization could promise a successful clinical examination of MPS to support the predictable treatment outcome of maxillary transverse deficiency.

A Deliberate Practice-Based Ultrasound Training Program for Fetal Palate Screening Using a Sequential Sector Scan Through the Oral Fissure

OBJECTIVES

To introduce an ultrasound training program for fetal palate screening by using a sequential sector scan through the oral fissure to train less experienced doctors and to investigate its effectiveness.

METHODS

Twenty doctors and several women at approximately 20-28 weeks of gestation with singleton pregnancies who provided informed consent were enrolled. The training program consisted of theory and practice training, several tests, and two surveys. Trainees were tested before training and immediately after training; for the latter, each item with a score that was less than 60% of the full score was again used for training with a reconstructed plan. Finally, a post-training test was completed.

RESULTS

The median theory scores, median practice scores, median language competence scores, and median self-assessment scores all increased significantly from the pre-training to post-training tests (P < .01). The median completion time for fetal palate scans decreased significantly from the pre-training to post-training tests (P < .01). The median questionnaire scores were 5.00 for pragmatism, 4.00 for content, 4.00 for scientific nature, and 5.00 for effectiveness.

CONCLUSIONS

The training program for fetal palate screening can effectively standardize and improve doctors' scans for fetal palates. In addition, the program feasibly allows for the incorporation of the scan sequence into fetal palate screening.

Diagnostic Accuracy of Prenatal Fetal Ultrasound to Detect Cleft Palate in High-Risk Fetuses: A Systematic Review and Meta-Analysis

OBJECTIVES

This systematic review and meta-analysis investigated the accuracy of prenatal fetal ultrasound (US) to detect cleft palate during the second and third trimester (12-36 weeks) of pregnancy in high-risk fetuses.

METHODS

Pubmed and Embase databases were searched for studies that performed prenatal fetal US (comparator) and postnatal examination (reference standard) in fetuses at high risk for orofacial clefts. Risk of bias among included studies was assessed using the QUADAS-2. Area under the summary receiver operating characteristic (SROC) curve and pooled sensitivity and specificity were calculated.

RESULTS

This meta-analysis included 7 studies involving 663 high-risk fetuses. The individual studies showed that prenatal fetal US accurately predicted the possibility of cleft palate in these fetuses. Pooled sensitivity was 87% (95% CI 71%-95%), pooled specificity was 98% (95%CI 90%-100%), and the area under the SROC curve was 0.98 (95% CI 0.97-0.99).

CONCLUSION

Second and third trimester fetal US has excellent sensitivity and specificity for the detection of cleft palate in high-risk pregnancies.

The application of three-dimensional ultrasound with reformatting technique in the diagnosis of fetal cleft lip/palate

OBJECTIVE

To evaluate the clinical value of three-dimensional ultrasound (3D-US) with reformatting technique in the diagnosis of fetal cleft lip/palate (CL/P), especially those involving the secondary palate.

METHODS

A total of 113 fetuses suspected with cleft lip (CL) on two-dimensional ultrasound (2D-US) were further evaluated by 2D-US and 3D-US with reformatting technique, in order to clarify the type of oral cleft. Lesions were classified as cleft lip (CL), cleft lip and alveolus (CLA), and cleft lip and palate (CLP) (including primary and secondary palate). All fetuses were followed until birth or termination of pregnancy. The diagnostic accuracies of 2D-US and 3D-US with reformatting technology were compared.

RESULTS

Both 2D-US and 3D-US with reformatting successfully detected CLs in the final 103 participants. Among these, 29, 25, and 49 cases were confirmed to have CL, CLA, and CLP, respectively. CL, CLA, and CLP were diagnosed by 2D-US in 34, 66, and 3 cases, respectively, and by 3D-US with reformatting technology in 31, 27, and 45 cases, respectively. The sensitivities of 2D-US and 3D-US with reformatting technology in the diagnosis of CLA were 80% (20/25) and 92.0% (23/25), respectively, and the difference was not statistically significant. For CLP, however, the sensitivities were 6.1% (3/49) and 91.8% (45/49), respectively (P < .001).

CONCLUSIONS

Both 2D-US and 3D-US with reformatting technique have high diagnostic accuracy for CL and CLA. However, 3D-US has a much higher diagnostic accuracy for CLP.

Absent 'superimposed-line' sign: novel marker in early diagnosis of cleft of fetal secondary palate

OBJECTIVES

To describe a novel sign, the 'superimposed-line' sign, for early diagnosis of cleft of the fetal secondary palate on two-dimensional imaging of the vomeromaxillary junction in the midsagittal view.

METHODS

This was a prospective evaluation of the superimposed-line sign using two-dimensional sonography (midsagittal view) in 9576 singleton fetuses referred for routine screening between 12 and 20 weeks of gestation. In this view, the vomer bone appears as a line superimposed on the distal two-thirds of the maxillary line, as the vomer fuses with the secondary palate in the midline. If there is a midline cleft of the secondary palate, the line formed by the palate is absent and hence only the vomer bone is visualized, creating a single line instead of the normal superimposed double line. Multiplanar three-dimensional (3D) views were assessed in cases in which the superimposed-line sign was absent.

RESULTS

The superimposed line was absent in 17 fetuses with a cleft of the secondary palate that was confirmed by 3D evaluation. Of these, 13 had defects involving the premaxilla and four had an isolated cleft of the secondary palate. Postnatal confirmation was available in all cases. The sign was useful in ruling out cleft of the fetal secondary palate in 32 high-risk cases with a family history of cleft palate. The superimposed-line sign had a sensitivity of 89.5% in detecting cleft of the secondary palate.

CONCLUSIONS

The superimposed-line sign is a new sonographic marker for evaluation of cleft of the fetal secondary palate; documentation of this sign proves the presence of both the palate and vomer in the midline. This marker can be demonstrated clearly in the late first trimester, allowing early diagnosis of secondary palatine cleft. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal ultrasound diagnosis of cleft palate without cleft lip, the new ultrasound semiology

OBJECTIVES

The aim of this study was to define the prenatal ultrasound semiology of cleft palate without cleft lip using 3D visualization of the fetal palate.

METHODS

A prospective longitudinal study was performed in our University Hospital Center from 2011 to 2018. The fetal secondary palate was studied in 3D, starting with 2D axial transverse ultrasound view. We defined a cleft palate as a disruption of the horizontal plate of the palatine bone of the secondary palate. Prenatal findings were correlated to anatomic postnatal examinations performed by a paediatric plastic surgeon.

RESULTS

Forty-three cases of cleft palate without cleft lip were prenatally diagnosed, of whom 34 were associated with malformations. We defined four types of disruptive appearances: isolated nonvisualization of the posterior nasal spine; partial-disruption or cleft velum; complete disappearance or V-shaped cleft palate; and complete disappearance or U-shaped cleft palate. The adjusted kappa coefficient, between prenatal and postnatal evaluation, was 0.88 (95% CI: 0.79-0.97), corresponding to an excellent agreement.

CONCLUSIONS

Using a strictly axial transverse ultrasound view, visualization of the secondary fetal palate enables to diagnose a cleft palate without cleft lip. This method offers a prenatal anatomic classification of cleft palate with a high level of concordance to postnatal findings.

Fetal tongue posture associated with micrognathia: An ultrasound marker of cleft secondary palate?

Cleft lip and cleft palate (CP) are the most common facial malformations. Two-dimensional (2D) ultrasound (US) is the first-line examination in the prenatal diagnosis of CP. Three-dimensional, four-dimensional US and MRI provide a better detection of facial clefts. We present two fetuses with micrognathia and suspected secondary CP on 2D US: fetal tongue appeared in an unusual position (low tip and high dorsum position) and showed uncoordinated movements. MRI did not confirm the US suspicion, but at birth the two fetuses were affected by Pierre Robin sequence.

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.

The solitary median maxillary central incisor (SMMCI) syndrome: Associations, prenatal diagnosis, and outcomes

Solitary median maxillary central incisor (SMMCI) syndrome is a complex disorder consisting of multiple, developmental defects involving midline structures of the head, which includes the cranial bones, the maxilla, and its container dentition (specifically the central incisor tooth germ), together with other midline structures of the body. SMMCI may appear as an isolated trait or in association with other midline developmental anomalies. We describe the case of a patient with SMMCI. He presented with a solitary median maxillary incisor, short stature, corpus callosum anomalies and a microform of holoprosencephaly (HPE), diabetes insipidus, and neurodevelopmental delay. The diagnosis was performed postnatally based on clinical features, radiological imaging, and a comprehensive genetic study. SMMCI can be diagnosed during the prenatal or neonatal periods or during infancy. Evaluation of the superior maxillary bone is important for prenatal diagnosis. Direct evaluation through bidimensional ultrasound or the use of multiplanar ultrasound or tridimensional reconstruction should be performed in cases of brain or face malformations. Early diagnosis can contribute to improved prenatal assessment and postnatal management.

How to obtain diagnostic planes of the fetal central nervous system using three-dimensional ultrasound and a context-preserving rendering technology

The antenatal evaluation of the fetal central nervous system (CNS) is among the most difficult tasks of prenatal ultrasound (US), requiring technical skills in relation to ultrasound and image acquisition as well as knowledge of CNS anatomy and how this changes with gestation. According to the International Guidelines for fetal neurosonology, the basic assessment of fetal CNS is most frequently performed on the axial planes, whereas the coronal and sagittal planes are required for the multiplanar evaluation of the CNS within the context of fetal neurosonology. It can be even more technically challenging to obtain "nonaxial" views with 2-dimensional (2D) US. The modality of 3-dimensional (3D) US has been suggested as a panacea to overcome the technical difficulties of achieving nonaxial views. The lack of familiarity of most sonologists with the use of 3D US and its related processing techniques may preclude its use even where it could play an important role in complementing antenatal 2D US assessment. Furthermore, once a 3D volume has been acquired, proprietary software allows it to be processed in different ways, leading to multiple ways of displaying and analyzing the same anatomical imaging or plane. These are difficult to learn and time consuming in the absence of specific training. In this article, we describe the key steps for volume acquisition of a 3D US volume, manipulation, and processing with reference to images of the fetal CNS, using a newly developed context-preserving rendering technique.

A score-based method for quality control of fetal hard palate assessment during routine second-trimester ultrasound examination

INTRODUCTION

When an orofacial cleft lip is discovered, precise characterization of this malformation is necessary, especially the extension of this cleft to the secondary palate. We aimed to develop and evaluate the feasibility/reproducibility of a score-based quality control for the visualization of the fetal hard palate during the second-trimester scan.

MATERIAL AND METHODS

All ultrasound images of fetal hard palate assessed routinely during second-trimester scan were retrospectively retrieved for a 6-month period. One hundred of these images were randomly selected and analyzed by two blinded reviewers, according to a scoring system (0-6 points). Criteria retained in the score were complete palate bone horizontal plate, presence of two pterygoid processes, visible alveolar ridge, and horizontal axis of insonation. A score ≥4 defined images of good quality. Inter- and intra-reviewer reproducibility was assessed.

RESULTS

Inter-reviewer reproducibility was excellent with significant correlation (Pearson coefficient 0.953; P < .0001), global adjusted κ coefficient (0.86, 95% CI 0.79-0.94) and individual criteria adjusted κ coefficient always > 0.8. Rates of images of good quality (score ≥ 4) were 75%-77%, also with excellent agreement (κ coefficient 0.89, 95% CI 0.79-0.99). Intra-reviewer reproducibility retrieved the same results (excellent agreement) except for the axis of insonation (satisfactory agreement).

CONCLUSIONS

This simple image scoring system for the fetal palate is easy, has excellent inter- and intra-reviewer reproducibility and could also help sonographers to correctly identify the palate structure.

First-Trimester Sonographic Evaluation of Palatine Clefts: A Novel Diagnostic Approach

OBJECTIVES

Sonographic evaluation of the palate is a difficult task, and most palatine clefts are diagnosed in the neonatal period because of the limitations of 2-dimensional (2D) sonography. The objective is to describe a sonographic technique based on 2D markers for screening of palatine clefts during the nuchal translucency scan and to assess the ability of 3-dimensional (3D) sonography in imaging the normal and abnormal palate.

METHODS

A total of 2014 women who enrolled for first-trimester screening were included in this prospective study. Screening for palatine clefts was done by 2D evaluation of bony landmarks of the palate, which were the appearance of the palatal line in the sagittal view, retronasal triangle in the coronal view, and alveolar ridge of the maxilla in the axial view followed, by 3D evaluation in suspicious cases. All cases included in the study were followed by second-trimester anomaly scans and evaluated postnatally. Additionally, in 100 consecutive normal cases, 3D evaluation of the palate was done.

RESULTS

Visualization of 2D landmarks could be done in all, and 3D assessment was feasible in 94% of cases. Fourteen cases, of which 5 were unilateral, 4 bilateral, and 2 median cleft lip and palate, 2 median cleft palate, and 1 atypical palatine cleft were identified. There were no false-positives results reported, and 1 case of a bifid uvula was missed.

CONCLUSIONS

The study demonstrates that evaluation of the palate can be done at the 11 to 14 week scan based on 2D markers and can also be assessed with 3D sonography. The inclusion of 2D markers in all 3 planes increases the sensitivity for detection of palatine clefts.

Analysis of Fetal Palate to Assist Pre-natal Ultrasound

INTRODUCTION

Cleft palate is one of the major facial congenital malformation in newborns. Pre-natal detection of this malformation is limited to detection of clefting of hard palate but isolated soft palate clefting still remains challenge for sonologists. As Indian literature is limited present study was attempted to provide dimensions and position of fetal palate by digitized images.

AIM

To study dimensions, position and differences in parameters between second and third trimester fetuses.

MATERIALS AND METHODS

Median sagittal section of 32 formalin fixed fetuses was selected from the Department of Anatomy, St John's Medical College, Bangalore, Karnataka, India. Anatomical landmarks-The Nasion (N), Sellaturcica (S), Anterior Nasal Spine (ANS), Posterior Nasal Spine (PNS), tip of Uvula (U) were marked on sections. Length of hard palate (from ANS to PNS), Length of soft palate (from PNS to U), Hard palate/soft palate angle was defined. The anterior position of soft palate and its posterior position in relation to anterior cranial base were marked as N-S-PNS and N-S-U angle, respectively. The measurements were acquired directly from the digitized images using ImageJ software. Statistical analysis was done using SPSS 16.

RESULTS

The mean values of ANS-PNS and PNS-U were 23.59±3.69mm and 14.39±2.70mm, respectively. The mean values of hard palate/soft palate angle, N-S-PNS and N-S-U angle were 144.720±11.11,51.150±9.09 and 93.370±9.58, respectively. Significant difference was noted between trimesters for length of hard and soft palate but not for palatal angles.

CONCLUSION

During Pre-natal assessment of cleft palate, it is important for sonologist to keep in mind that the dimensions of palate proportionately increased in last two trimesters while the position remains constant.

Ultrasound Evaluation of Primary Alveolar Grafting in Cleft Lip/Palate Treatment: Development of a Novel Sonographic Grading System

Objective

To explore ultrasonographic evaluation of primary alveolar repair in cleft lip/palate patients and develop a grading system to assess outcomes of graft success.

Design

Sixteen patients with an average age of 2 years 1 month had sonograms performed at various points in their treatment to determine the feasibility of ultrasound in visualizing alveolar bone defects and changes over time postgrafting. A total of 23 sonograms were performed: 21 at an average of 12 months postoperatively and 2 at an average of 1 month preoperatively.

Main Outcome Measures

A 10-point grading system was developed assessing three categories: locations of lateral bone bridging across the cleft, quantification of residual defects with air or fluid channels, and locations of calcification. Three operators graded 10 sonograms to assess interobserver reliability, and the scores were also validated against dental radiographs in patients old enough for radiographic imaging.

Results

Linear weighted kappa statistics revealed substantial interobserver agreement for total scores, with an average kappa value of .708. In limited patients with radiographs, a total score of 9/10 correlated with a Chelsea score of 6.5/8 and category A.

Conclusions

Sonographic evaluation, coupled with this novel grading system, shows potential for early assessment of outcomes of graft success when evaluating new techniques of primary alveolar grafting.

Fetal and neonatal maxillary ontogeny in extant humans and the utility of prenatal maxillary morphology in predicting ancestral affiliation

OBJECTIVES

The midface of extant Homo sapiens is known to undergo shape changes through fetal and neo-natal ontogeny; however, little work has been done to quantify these shape changes. Further, while midfacial traits which vary in frequency between populations of extant humans are presumed to develop prenatally, patterns of population-specific variation maxillary shape across ontogeny are not well documented. Only one study of fetal ontogeny which included specific discussion of the midface has taken a three-dimensional geometric morphometric approach, and that study was limited to one population (Japanese). The present research project seeks to augment our understanding of fetal maxillary growth patterns, most especially in terms of intraspecific variation.

MATERIALS AND METHODS

Three-dimensional coordinate landmark data were collected on the right maxillae of 102 fetal and neo-natal individuals from three groups (Euro-American, African-American, "Mixed Ancestry").

RESULTS

Shape changes were seen mainly in the lateral wall of the piriform aperture, the anterior nasal spine, and the subnasal alveolar region. The greatest difference across age groups (second trimester, third trimester, neonates) was between the second and third trimester. Euro-Americans and African-Americans clustered by population and differences in midfacial morphology related to ancestry could be discerned as early as the second trimester (p = .002), indicating that population variation in maxillary morphology appears very early in ontogeny.

DISCUSSION

The midface is a critical region of the skull for assessing ancestry and these results indicate that maxillary morphology may be useful for estimating ancestry for prenatal individuals as young as the second trimester.

Role of 3-D ultrasound in clinical obstetric practice: evolution over 20 years

The use of 3-D ultrasound in obstetrics has undergone dramatic development over the past 20 years. Since the first publications on this application in clinical practice, several 3-D ultrasound techniques and rendering modes have been proposed and applied to the study of fetal brain, face and cardiac anatomy. In addition, 3-D ultrasound has improved calculations of the volume of fetal organs and limbs and estimations of fetal birth weight. And furthermore, angiographic patterns of fetal organs and the placenta have been assessed using 3-D power Doppler ultrasound quantification. In this review, we aim to summarize current evidence on the clinical relevance of these methodologies and their application in obstetric practice.

Current Role of 3D/4D Sonography in Obstetrics and Gynecology

Modern 3D/4D sonography provides a routine method not only for storing single image planes as in 2D ultrasound but also for storing complete sets of volume data in the computer memory. Once acquisition is completed, all volumes can be accessed from the memory and normal and abnormal findings in both obstetrics and gynecology can be demonstrated in different display modes. Furthermore digital storage of volumes permits virtual examinations by reloading of volumes and navigating through them in the absence of the patient.

This review article would like to give an illustration of the latest technologies in 3D/4D ultrasound in obstetrics and gynecology.

How to cite this article

Merz E, Pashaj S. Current Role of 3D/ 4D Sonography in Obstetrics and Gynecology. Donald School J Ultrasound Obstet Gynecol 2013;7(4):400-408.

First-trimester assessment of the fetal palate: a novel application of the Volume NT algorithm

We describe a new technique that can facilitate the first-trimester examination of the fetal palate using the Volume NT algorithm (Samsung Medison, Seoul, Korea), a program that automatically detects the exact midsagittal plane of the head and is primarily designed for semiautomatic measurement of the nuchal translucency thickness. Three-dimensional (3D) data sets from the fetal face were captured with Volume NT and subsequently reformatted with the Oblique View software to obtain orthogonal views of the primary and secondary palate in coronal and axial planes, respectively. By testing this method in selected 3D data sets obtained retrospectively (n = 12) and prospectively (n = 28), we were able to extract clinically acceptable views of the fetal palate in all cases. This preliminary report shows that with this new 3D automation development, early evaluation of the fetal palate is feasible and reproducible and could be easily incorporated into the first-trimester sonographic protocol once its ability to detect abnormal cases is demonstrated.

OmniView algorithm: a novel 3-dimensional sonographic technique in the study of the fetal hard and soft palates

The purpose of this pictorial essay is to report on the application of OmniView (GE Healthcare, Zipf, Austria), new 3-dimensional sonographic software, and its application in the prenatal sonographic study of the fetal hard and soft palates. We will show that this novel technique is easy and feasible, requires a limited learning curve, and provides correct volume interrogation of the region of interest. The OmniView algorithm may be useful in training programs, and volume data sets can be interpreted by experts in remote sites. Future prospective studies with consecutive patients will be necessary to evaluate whether the routine application of OmniView will increase the prenatal diagnosis of facial clefting, especially those with isolated palate defects.

An Investigation into the Morphometric Developments of the Maxillary and Mandibular Arches during the Fetal Period

Objective

The objective of this study was to determine the developments, morphometric features, and shapes of the maxillary and mandibular arches during the prenatal period in a large series of fetal material.

Methods

The study was carried out on 225 human fetuses aged between 8 and 40 weeks of gestation. General, extraoral, and intraoral parameters were taken from each fetus. The width and depth measurements and the shapes of the maxillary and mandibular arches were achieved using the casts obtained. The arches were categorized according to the shapes of the anterior and posterior regions of the arches.

Results

Palatal and mandibular indices did not change during the prenatal period. Maxillary arch measurements were greater than the mandibular measurements. Moreover, width measurements of both arches were greater than the depth measurements during fetal life. We found that the frequencies of triangular maxillary and mandibular arches were highest in the first and second trimesters; whereas, the square model became more frequent in the third trimester and at full term. Classification of the arches according to their posterior regions showed that the tips of the arches shifted medially toward the term. There were significant correlations between width and depth parameters of the arches and extraoral parameters.

Conclusion

Data obtained in the study would be useful for clinicians by presenting an objective scale related to the prenatal period as well as being helpful in assessing the development of this region, identifying the anomalies and pathologies, and assisting treatment.

Feasibility of 3-dimensional sonographic examination of the fetal secondary palate during the second-trimester anatomy scan

OBJECTIVES

To determine the feasibility of obtaining adequate 3-dimensional (3D) data sets to examine the fetal secondary palate during the second-trimester anatomy scan.

METHODS

During a 3-month period, 3D data sets of the fetal secondary palate were obtained from consecutive women undergoing routine second-trimester scans. Only structurally normal singleton fetuses with a normal upper lip on 2-dimensional (2D) sonography were included. Three-dimensional data sets were obtained using a mechanical transducer with a 45° sweep and the same settings as for the standard 2D scan, ideally when the fetus was facing the transducer, with mild extension of the head, and the ultrasound beams projecting caudally to cranially to avoid shadowing from the primary palate or mandible. No additional scanning time was allocated for examination of the palate. Acquired 3D data sets were analyzed offline using dedicated software, and the secondary palate was assessed using the "flipped face" technique.

RESULTS

Ninety-seven women met entry criteria and underwent second-trimester scans at a median gestational age of 22 completed weeks (range, 18-23 weeks). In 13 (13.4%) cases, it was not possible to obtain a midsagittal view of the face for capturing 3D volume data sets due to fetal position. Additional factors limiting visualization were shadowing from the primary palate in fetuses with flexion of the head in 30 (30.9%) cases, interposition of, or shadowing from, fetal arms or legs in 11 (11.3%), inability to reproduce a true midsagittal plane in 8 (8.2%), and poor image quality in 1 (1%). Therefore, it was only possible to assess the secondary palate in 34 (35.1%) cases.

CONCLUSIONS

It is not feasible to obtain adequate 3D data sets for offline analysis of the fetal secondary palate in almost two-thirds of second-trimester fetuses during the routine scan. However, suboptimal visualization is primarily due to factors related to fetal position rather than equipment or image quality. This finding suggests that a dedicated scan, during which adequate time can be devoted to obtaining a satisfactory position in which the fetal face can be evaluated, may be warranted in high-risk cases.

Accuracy of prenatal three-dimensional ultrasound in the diagnosis of cleft hard palate when cleft lip is present

OBJECTIVE

To investigate the accuracy of prenatal axial three-dimensional (3D) ultrasound in predicting the absence or presence of cleft palate in the presence of cleft lip.

METHODS

Between March 2005 and January 2009, there were 81 cases with a prenatal two-dimensional (2D) ultrasound screening diagnosis of unilateral or bilateral cleft lip at 22-25 weeks of gestation referred to our tertiary care center. Of these, 79 fetuses were included in this prospective study and two were excluded. Axial 3D ultrasound imaging of the fetal palate was performed and the diagnoses were compared with clinical findings at delivery. The frequencies of intact and cleft palate, the degree of association between the prenatal predictions and postnatal findings and the probability of detection of cleft lip and palate were determined.

RESULTS

Of 79 prenatal predictions, 77 (97%) were correct and the association between the prenatal predictions and postnatal findings was strong. The sensitivity for detection of cleft lip and palate within this high-risk population was 100% and the specificity was 90%. In one of the excluded cases, the palate could not be visualized due to a fetal prone position. There were chromosomal anomalies in 4% of cases and associated structural or growth anomalies in 23%, termination of pregnancy was carried out in 4% and intrauterine fetal demise occurred in 3%.

CONCLUSION

Axial 3D ultrasound of the fetal palate has high accuracy in identifying prenatal cleft palate when cleft lip is diagnosed at mid-trimester 2D ultrasound screening.

Prenatal Assessment of the Antero-Posterior Jaw Relationship in Human Fetuses: From Anatomical to Ultrasound Cephalometric Analysis

Objectives

We wished to develop an ultrasound cephalometric analysis, particularly of the antero-posterior jaw relationship, to increase the accuracy of prenatal diagnosis of retrognathism during the routine midterm test.

Methods

Anatomical cephalometric analysis was performed in 18 formalin-fixed human fetuses (between 16 and 39 gestational weeks), and ultrasound cephalometry was prospectively carried out in 52 pregnant women (21 to 25 gestational weeks). The same landmarks were used in the anatomical and ultrasound median sagittal planes for comparison. Four cephalometric angles were measured relative to the anterior cranial base: alveolar projection of the maxilla and the mandible, chin projection, and facial angle. The antero-posterior jaw discrepancy was calculated.

Results

The projection of the maxilla was similar in the two cephalometric analyses (IC [–3.39, 0.23]), whereas the values of the projection of the mandible were lower in the ultrasound sample. The slope of the regression line of the antero-posterior jaw discrepancy on fetuses' age did not show significant differences (IC [–0.05, 1.54]) between anatomical and ultrasound cephalometry, although a difference of 3.23° ± 0.78° (IC [1.69, 4.77]) was observed. Despite this variability, the projections of mandible and chin were well determined by the projection of the maxilla both in the anatomical and ultrasound sample.

Conclusions

Cephalometric analysis by prenatal sonography can be performed to study the antero-posterior jaw relationship. We think that this procedure could be useful to improve prenatal diagnosis of retrognathism in high-risk pregnancies. Further studies should address the reproducibility and accuracy of such analysis.

Benefits of a systematic approach in the evaluation of fetal facial 3-dimensional volumes

OBJECTIVES

The purpose of our study was to evaluate the accuracy and efficacy of using a systematic approach to teach maternal-fetal medicine physicians how to display a diagnostic fetal profile and palate using 3-dimensional ultrasonography (3DUS).

METHODS

Ten maternal-fetal medicine physicians were randomly assigned to 2 groups, A and B, and instructed on basic principles of 3DUS volume manipulation. Physicians in group A were asked to display the fetal profile in 5 volumes, including 1 fetus with abnormalities. Physicians in Group B were asked to display the fetal profile in the same 5 volumes after detailed instruction. The groups were combined, and detailed instruction was repeated. The physicians were asked to review an additional 5 volumes. In a separate session, the physicians were divided into their respective groups, and a similar exercise was repeated. This time, they were asked to display the fetal palate in 3-orthogonal-plane and parallel-plane images. The time required for manipulation was recorded. Images were reviewed for accuracy and clinical utility by 2 blinded experienced sonologists. Data were analyzed with mixed effects models.

RESULTS

Fetal profile and parallel-plane palate scores were significantly higher in group B (P < .001) compared to group A. There was no difference between groups in displaying the 3-orthogonal-plane image of the palate or after additional training for either group. The mean times for display did not differ between the groups. The time required for evaluation of the abnormal profiles was longer (P = .02) than that for evaluation of the normal profiles.

CONCLUSIONS

Detailed instruction in obtaining 3DUS images of fetal profiles and palates improved the image quality obtained by physicians. Teaching physicians in a standardized way may help improve the use of 3DUS in clinical practice.

MRI for Definitive In Utero Diagnosis of Cleft Palate: A Useful Adjunct to Antenatal Care?

Objective

To assess the use of fetal magnetic resonance imaging (MRI) in obtaining a definitive prenatal diagnosis of cleft palate.

Design

All expectant mothers with a sonographically diagnosed fetal cleft lip or a previously affected child with cleft palate were offered antenatal MRI at around 34 weeks' gestation. Images were interpreted by a consultant radiologist who was blinded to the ultrasound diagnosis. Two MRI readings were performed: one at the time of examination and one at the end of the study to elicit the radiologist's learning curve. MRI findings were correlated with the birth diagnosis.

Setting

Tertiary referral center for facial clefts—the Spires Cleft Centre, Oxford Children's Hospital, Oxford, United Kingdom.

Participants

Study participants included 49 pregnant women between 24 and 37 weeks' gestation, four with a family history of cleft posterior palate and 45 with a facial cleft on a 20-week ultrasound.

Results

The positive predictive value of fetal MRI for involvement of the palate was 96%, and the negative predictive value was 80%. The accuracy in predicting palatal clefting of four different MRI signs is discussed. The radiologist's interpretation skills significantly improved between the two MRI readings.

Conclusions

Fetal MRI enables us to predict accurately the extent of a cleft palate after an ultrasound diagnosis of cleft lip. With more accurate diagnosis of the severity of the cleft, we can counsel patients more precisely and plan postnatal management correctly.

Detection of lip, alveolar ridge and hard palate abnormalities using two-dimensional ultrasound enhanced with the three-dimensional reverse-face view

OBJECTIVE

The aim of this study was to assess conventional two-dimensional (2D) ultrasound enhanced with a three-dimensional (3D) ultrasound technique, the 'reverse-face' view (3D-RF) in prenatal evaluation of the involvement of the lips, alveolar ridge and secondary palate in suspected isolated orofacial clefting.

METHODS

One hundred and twenty-four cases of suspected orofacial clefting diagnosed by a routine 2D ultrasound scan were referred for specialist ultrasound at 20-34 weeks' gestation for a detailed assessment of the lips and palate using both 2D and 3D ultrasound. For the 3D examination the lips and alveolar ridges were examined both in profile and in the frontal plane. The palate was then assessed in the reverse coronal view by rotating the face through 180° on the vertical axis to produce the 3D-RF view. Antenatal diagnoses were compared with postnatal findings. Left and right lip and alveolar ridge defects were counted separately according to the Kernohan 'striped Y' classification.

RESULTS

Of 124 patients, 110 had isolated facial clefts and were available for follow-up; in 10, 3D-RF views were not successfully obtained, leaving 100 cases for assessment. The sensitivity of the 2D enhanced with 3D-RF technique for the diagnosis of cleft of the lip was 116/122 (95%), false-positive rate (FPR) 7.7%; for alveolar ridge was 87/103 (84.5%), FPR 7.2%; and for hard palate was 61/68 (89.7%), FPR 15.6%.

CONCLUSION

The data reported represent the largest series of orofacial abnormalities diagnosed by 2D ultrasound and enhanced with 3D imaging to refine the detection of clefts of the hard palate. The technique is feasible in 90% of patients in whom almost 90% have a correct classification of clefts of the lip, alveolar ridge and palate.

Three-dimensional ultrasound in evaluating the fetus

In recent years three-dimensional (3D) ultrasound has made a place in clinical practice and has become a major field of research in obstetrics. In this article we will review the diagnostic performance of the most widely used 3D ultrasound applications in the assessment of fetal anomalies, explain the technique to gain correct 3D images and offer some practical advice for their efficient use. Examples are given to demonstrate the applicability and vividness of 3D in daily routine.

The 'equals sign': a novel marker in the diagnosis of fetal isolated cleft palate

OBJECTIVES

To determine the feasibility of visualization of the uvula and the soft palate during routine two-dimensional (2D) ultrasound examination and to develop a sonographic procedure that facilitates prenatal detection of isolated fetal cleft palate.

METHODS

We examined 667 consecutive patients with a singleton pregnancy between 20 and 25 weeks of gestation who were referred to our practice for a detailed fetal anomaly scan. The uvula was visualized either in a frontal section through the neck and pharynx or via a transverse section with subsequent slight tilting of the transducer. The soft palate was visualized in a median sagittal section through the head. To test whether the techniques described are suitable for inclusion in routine examinations, the time allowed for a normal ultrasound scan was not changed from 30 min.

RESULTS

A normal uvula could be visualized with a typical echo pattern (the 'equals sign') in 90.7% of the cases and the soft palate could be completely visualized in a median sagittal section in 85.3% of the cases. Visualization of at least one of the two structures (either the uvula or the soft palate) was successful in 98.4% of the cases. In one case an isolated cleft palate (in an otherwise normal fetus) was diagnosed; in one case with a cleft lip and palate, the cleft palate and the completely split uvula were detected. In 1.2% of the cases the examination did not provide sufficient information on either the uvula or the soft palate.

CONCLUSIONS

In a high percentage of cases, relevant soft palate structures can be visualized successfully with 2D ultrasound, permitting cleft palate to be ruled out in routine examinations. Visualization of the equals sign proves an intact palate. Absence of the equals sign indicates cleft palate and should prompt further examination of the soft palate in a median sagittal section. Cleft palate can be confirmed when the soft palate cannot be visualized. This technique also facilitates evaluation of the soft palate in the event of a cleft lip and palate.

Evaluation of the fetal secondary palate by 3-dimensional ultrasonography

OBJECTIVE

Diagnosis of cleft lip and palate remains a challenge with 2-dimensional ultrasonography, particularly when clefting involves only the secondary palate. The utility of 3-dimensional ultrasonography (3DUS) has enhanced our ability to detect clefts. We report our experience with a modification of the flipped face technique to aid in the diagnosis of clefting of the secondary palate.

METHODS

Ninety-two volumes of 92 fetal faces were evaluated. Thirty-six volumes were acquired prospectively. Fifty-six volumes had previously been acquired and included 8 with clefting of the secondary palate. Volumes were obtained on 3DUS systems and reviewed by 4 blinded readers on personal computer workstations. Volumes were manipulated so that an upright profile was visualized. The palate was then rendered using a thin, curved render box. Statistical analysis was performed using the Fisher exact test for categorical data. Intraclass correlations were computed to assess inter-rater agreement.

RESULTS

The mean gestational age at image acquisition +/- SD was 22 +/- 5 weeks. Image quality of the secondary palate was obtained and rated as adequate by at least 2 reviewers in 34% (31 of 92) of volumes. The sensitivity of cleft detection ranged from 33% to 63%, and the specificity ranged from 84% to 95%. The low sensitivity was mainly due to artifacts/shadowing. The inter-rater reliability was 0.62 (95% confidence interval, 0.47-0.76).

CONCLUSIONS

Three-dimensional ultrasonography can be used to diagnose clefts of the secondary palate. This evaluation is limited by the fetal position and artifacts from shadowing of adjoining structures. Pseudoclefts can be created, and optimal imaging cannot be obtained in all fetuses.

Sonographic Imaging of the Fetal Hard Palate During the Second-Trimester Pregnancy Scan

Cleft lip and cleft palate are among the more common congenital abnormalities, representing the fourth most common birth defect in the United States, with an incidence of 1 in 700 live births. The study of fetal secondary palate has reached new potential due to new 3D applications— namely, tomographic sonography imaging and volume contrast imaging (VCI). The aim of this review is to describe the 3D sonographic setting for a systematic study of the fetal secondary palate during second-trimester pregnancy. Sonographers can easily achieve appropriate training in 3D scanning of the fetal face under expert tutoring. The sonographic study of the fetal secondary palate should become an integral part of the second-trimester scan. Technically, the axial and coronal sections are those that better display the 3D reconstruction, especially when the fetus is facing the transducer (profile section). The use of static VCI may enhance tomographic sonography imaging of the fetal secondary palate and should therefore be integrated in this target examination.

Examination of the secondary palate on stored 3D ultrasound volumes of the fetal face

OBJECTIVES

To examine the use of oblique planes from stored three-dimensional (3D) ultrasound volumes of the fetal face for viewing the secondary palate at various gestational ages.

METHODS

3D ultrasound volumes of the fetal face acquired with surface rendering at 15-35 weeks' gestation in 31 fetuses with confirmed normal secondary palates were reviewed. The secondary palate was viewed in three oblique planes targeted at the uvula: the oblique axial, the oblique sagittal and the reverse face view. The detection and appearance of the secondary palate, including the soft palate, with these views at various gestational ages were compared.

RESULTS

The various surfaces of the secondary palate could be viewed in all 31 fetuses in the oblique axial and the reverse face views, and in all except two fetuses in the oblique sagittal view. Both of these were < 19 weeks' gestation, at which age the uvula could not be identified clearly in this plane.

CONCLUSIONS

The oblique axial, the oblique sagittal and the reverse face view targeted at the uvula allow visualization of the various aspects of the fetal secondary palate on 3D ultrasound in the second and third trimesters of pregnancy. The uvula could be used as a landmark for viewing the soft palate, but was not always easily identifiable before 19 weeks' gestation.