Three-dimensional sonographic description of the fetal frontal bones and metopic suture

A multi-omic atlas of human embryonic skeletal development

Human embryonic bone and joint formation is determined by coordinated differentiation of progenitors in the nascent skeleton. The cell states, epigenetic processes and key regulatory factors that underlie lineage commitment of these cells remain elusive. Here we applied paired transcriptional and epigenetic profiling of approximately 336,000 nucleus droplets and spatial transcriptomics to establish a multi-omic atlas of human embryonic joint and cranium development between 5 and 11 weeks after conception. Using combined modelling of transcriptional and epigenetic data, we characterized regionally distinct limb and cranial osteoprogenitor trajectories across the embryonic skeleton and further described regulatory networks that govern intramembranous and endochondral ossification. Spatial localization of cell clusters in our in situ sequencing data using a new tool, ISS-Patcher, revealed mechanisms of progenitor zonation during bone and joint formation. Through trajectory analysis, we predicted potential non-canonical cellular origins for human chondrocytes from Schwann cells. We also introduce SNP2Cell, a tool to link cell-type-specific regulatory networks to polygenic traits such as osteoarthritis. Using osteolineage trajectories characterized here, we simulated in silico perturbations of genes that cause monogenic craniosynostosis and implicate potential cell states and disease mechanisms. This work forms a detailed and dynamic regulatory atlas of bone and cartilage maturation and advances our fundamental understanding of cell-fate determination in human skeletal development.

Radiological Diagnosis of Crouzon Syndrome: A Case Study

Crouzon syndrome, distinguished by a classic trio of an atypical skull structure, distinctive facial features, and protruding eyes, ranks among the most prevalent types of craniofacial dysostosis. Therefore, patients presenting with dental abnormalities are under-reported in medical literature despite the developmental neurological defects. We report a rare case of Crouzon syndrome in a four-year-old girl who had forward displacement of the lower jaw, bulging eyes, undeveloped upper jaw, and dental abnormalities. She was evaluated with cranial computed tomography with three-dimensional reconstruction; genetic studies confirmed the findings.

Incidence of persistent metopic suture in Australia: findings from 1034 three-dimensional computed tomography scans

PURPOSE

To investigate the incidence of persistent, open metopic sutures in contemporary Australians aged 24 months and older.

METHODS

Metopic suture evaluation was conducted on retrospective cranial/cervical computed tomography scans of patients aged 24 to 252 months who presented to the Women's and Children's Hospital in Adelaide, Australia, between 2010 and 2020. Suture ossification was graded according to Lottering scoring system based on 4 stages, on three-dimensional volume-rendered reconstructions (stage 1: fibrous tissue interface, stage 2: commenced fusion, stage 3: complete fusion and stage 4: obliterated suture). The complete persistent sutures were classified as stage 1. Partially closed sutures were classified into stages 2 and 3, while completely closed sutures were defined as stage 4.

RESULTS

One thousand thirty-four patients (61.2% male and 38.8% female) were included, with a mean age at scan of 66 months. More than half of patients were subject to scanning due to closed-head injuries. The incidence of persistent (completely open) metopic suture was 4.8% (2.3% in males and 2.5% in females). In comparison, a partially closed metopic suture was found in 6.3% of the study cohort, with the remaining sutures located along the metopic suture line, at the glabella, mid-part of the suture, bregma and glabella-bregma areas.

CONCLUSION

The prevalence of persistent metopic sutures in our study of the Australian population is 4.8%, and it is equally distributed between the genders. The pattern of suture closure can commence from any location along the suture line, which is in contrast to the existing literature.

Prenatal diagnosis of Meier-Gorlin syndrome 7: a case presentation

Background

Meier-Gorlin syndrome 7 (MGS7) is a rare autosomal recessive condition. We reported a fetus diagnosed with Meier-Gorlin syndrome 7. The antenatal sonographic images were presented, and compound heterozygous mutations of CDC45 on chromosome 22 were identified by whole-exome sequencing (WES).

Case presentation

Fetal growth restriction (FGR), craniosynostosis, and brachydactyly of right thumb were found in a fetus of 28th gestational weeks. The fetus was diagnosed as MGS7 clinically. After extensive counseling, the couple opted for prenatal diagnosis by cordocentesis and termination of pregnancy. Karyotype analysis and WES were performed. Chromosomal karyotyping showed that the fetus was 46, XY. There were 2 mutations of CDC45, the causal gene of MGS7 on chromosome 22, which were inherited from the couple respectively were identified by WES. Facial dysmorphism, brachydactyly of right thumb, and genitalia abnormally were proved by postpartum autopsy, and craniosynostosis was confirmed by three-dimensional computed tomography (3D-CT) reconstruction.

Conclusions

It is possible to detect multiple clinical features of Meier-Gorlin syndrome in prenatal sonography. Deteriorative FGR complicated with craniosynostosis indicates MGS7. Combination of 2D and 3D ultrasonography helps to detect craniosynostosis. The affected fetus was confirmed a compound heterozygote of CDC45 related MGS by whole-exome sequencing, which is critical in identifying rare genetic diseases.

Temporal mapping of the closure of the anterior fontanelle and contiguous sutures using computed tomography, in silico models of modern infants

The aim of this study is to quantify and statistically model the age-related decline in the fibrous connective tissue interface of the anterior fontanelle in modern Australian infants, using three-dimensional, semi-automated computed-assisted design protocols. Non-linear regression with variance models, using power functions, combined with quantile regression of the 5th and 95th population percentiles, were utilised to assess absolute anterior fontanelle surface area (AFSA) as a function of age, using multi-slice cranial computed tomography scans obtained from 256 infants aged < 30 months (males: n = 126, females: n = 109) from Brisbane children's hospitals. Normalised AFSA (NFSA), standardised for variation in cephalic size, followed a progressive decline from birth, the greatest velocity change occurring between the 3-6 and 6-9 month cohorts. Growth of the neurocranium is the most significant within the first 8 months postpartum, with a mean increase of 19.03 mm in maximum cranial length and 10.04 mm in breadth. Directionality of fontanelle closure, quantified using spline curves refutes fundamental assumptions that the anterior fontanelle is consistent with a quadrilateral, and contiguous sutures exhibit constant velocity of closure. The present study provides normative values for fontanelle size and diameters as well as new predictive non-linear models for age substantiation, screening of developmental abnormalities and indicators of suspected child maltreatment in modern infants aged birth to 30 months.

Morphometric study of the primary ossification center of the frontal squama in the human fetus

PURPOSES

Detailed morphometric data on the development of ossification centers in human fetuses is useful in the early detection of skeletal dysplasias associated with a delayed development of ossification centers and their mineralization. Quantitative analysis of primary ossification centers of cranial bones is sporadic due to limited availability of fetal material.

MATERIAL AND METHODS

The size of the primary ossification center of the frontal squama in 37 human (16 males and 21 females) spontaneously aborted human fetuses aged 18-30 weeks was studied by means of CT, digital-image analysis and statistics.

RESULTS

With neither sex nor laterality differences, the best-fit growth dynamics for the primary ossification center of the frontal squama was modelled by the following functions: y = 13.756 + 0.021 × (age)² ± 0.024 for its vertical diameter, y = 0.956 + 0.956 × age ± 0.823 for its transverse diameter, y = 38.285 + 0.889 × (age)² ± 0.034 for its projection surface area, and y = 90.020 + 1.375 × (age)² ± 11.441 for its volume.

CONCLUSIONS

Our findings for the primary ossification center of the frontal squama may be conducive in monitoring normal fetal growth and screening for inherited faults and anomalies of the skull in human fetuses.

The Intraosseous Dysfunction in the Osteopathic Perspective: Mechanisms Implicating the Bone Tissue

The somatic dysfunction (SD) is a protagonist in the context of theories and practices involving osteopathy and various other manual therapy methods. It is considered an obstacle to the body's inherent self-regulatory capabilities, and several tissues may be involved in this dysfunctional process, including the bone. The so-called intraosseous dysfunction refers to the restriction of natural flexibility of the fibrous components of the bone tissue matrix, or of the nonossified cartilaginous or membranous areas. Bone is a connective tissue composed of inorganic material and specialized cells organized in a hydrated extracellular matrix that provides the mechanical qualities to the tissue. The development of the bone tissue is a continuous process throughout life, and some bones fuse only years or decades after birth. It has microanatomical continuity with other adjacent structures and its different compartments are supplied by fluids, as well as somatic and autonomic innervation. Several studies show the phenomenon of bone tissue sensitization under traumatic, pathological conditions and also movement restriction. The purpose of the article is to review well-established knowledge and recent scientific findings regarding bone tissue anatomy and physiology, in an attempt to offer insights that could be applied to better understand the mechanisms implicating the intraosseus dysfunctions and its local and global repercussions.

Imaging diagnosis of Crouzon syndrome in two cases confirmed on genetic studies - with a brief review

Crouzon syndrome is the most common form of craniofacial dysostosis, characterised by a classical triad of abnormal skull shape, abnormal facies, and exophthalmos. The clinically overt dental abnormalities in these patients, distracts clinicians from the developmental neurological defects and therefore this entity remains relatively under - highlighted in radiology literature. We report and highlight the role of imaging in diagnosis of Crouzon syndrome in two patients, and discuss the relevant differential diagnosis. Moreover, our report is among the few Indian studies in which Crouzon syndrome was confirmed by genetic studies. The classical clinical triad of Crouzon syndrome was observed in both patients. The skull radiographs and cranial CT with 3D reconstruction VRT (Volume rendered technique), revealed characteristic radiological features. Genetic studies reconfirmed the clinical and radiological diagnosis of Crouzon syndrome, in both patients.

Why do metopic sutural synostoses angulate? The concept of nasion sutural complex and its implication on the management of hypotelorism-early results and proof of concept

OBJECT

Angulation at the suture is a hallmark of metopic synostoses amongst all craniosynostoses. No other sutural synostoses demonstrate angulation at synostoses consistently. We look into the possible aetiology and the implication of the understanding in the treatment goals of trigonocephaly. We hypothesise that the nasal bone and nasofrontal suture viz. "nasion sutural complex" are involved in trigonocephaly along with the well-accepted role of metopic suture. We propose that it is the angulation at this junction which leads to trigonocephaly and its secondary features.

MATERIALS AND METHODS

The study included seven infants, who underwent correction for trigonocephaly at our paediatric craniofacial division at Amrita Institute of Medical Sciences and Research Centre, Kochi, India, between the period July 2015 to March 2018. The cohort included were infants with trigonocephaly who had CT head for diagnosis. We analysed the multidimensional CT (MDCT) of these infants and compared to an equal number of age-matched controls. The controls were infants with other forms of sutural synostosis with metopic uninvolved and normal infants where MDCT was done for other reasons. Sutural characteristic at the nasion and metopic suture recorded in comparison with an equal number of age-matched controls. We performed spring cranioplasty for three infants after metopic suturectomy, extending the release beyond the nasion sutural complex, placing springs to distract the suture. The infants who underwent spring cranioplasty were followed up for the aesthetic outcome. Remaining infants of the study underwent standard frontorbital correction for metopic craniosynostoses.

RESULTS

We could demonstrate a fusion of nasofrontal and nasal suture in all cases (n = 7) of trigonocephaly included in the study on MDCT and intraoperatively. We performed spring cranioplasty for three infants (n = 3/7), where we released the internasal suture. At 3 months follow-up, along with correction of the angulation, the hypotelorism improved significantly. Other infants in the study (4/7) underwent classical frontorbital advancement.

CONCLUSIONS

Fusion of nasion sutural complex along with metopic sutures may explain the angulation in trigonocephaly. We propose that all minimally invasive techniques for correction of trigonocephaly and associated hypotelorism should consider this fact for an improved outcome.

Morphological variation in the anterior cranial fossa

The anterior cranial fossa is an important anatomical landmark in clinical orthodontics consisting of the frontal, ethmoid, and sphenoid bones. The relationships between these bones remain poorly understood. The purposes of the present study were to describe the morphological relationships among the three bones and to discuss the factors contributing to individual variations in adult skulls based on postnatal development. Skulls of 100 Indian adults and 18 Japanese juveniles were observed both macroscopically and using computed tomography images in the median sagittal plane. Three types of relationship were seen among the three bones in adult skulls: (a) a triangular border between ethmoid and sphenoid bones (ethmoid spine), (b) a straight or concave border between ethmoid and sphenoid bones, and (c) frontal bone lying between the ethmoid and sphenoid bones. In the juvenile skull, structures corresponding to those in adults were observed. These three bones comprise the anterior cranial base, each with differing developmental processes, and slight differences in these processes seem to be reflected in the morphological variations seen among adults.

Osteological evidence of metabolic diseases from a post medieval North Italy archaeological site

Skeletal lesions related to metabolic diseases in children have been systematically investigated in paleopathological literature only in recent years. This work presents an infant pathological specimen from the post-medieval cemetery of the St. Mary's Nativity church (15th-18th centuries, Segno, Trento, Trentino, Northeast Italy). The bones belonged to an individual of 9 ± 3 months of age, estimated upon an assessment of the stage of dental eruption. Metabolic diseases were diagnosed with paleopathological criteria according to previous literature. Differential diagnosis of the osteological evidence indicates a disease that might be caused by the lack of vitamin D or C. Comorbidity of vitamin C and D deficiency has been widely studied in clinical literature, particularly in children between 3 months and 5 years of age. The study of ancient osteoarchaeological materials allows us to improve our knowledge on diseases' effects on bone development in children and, in this case, it represents additional evidence of the presence of metabolic diseases in a rural contest of the Italian post-medieval period.

Crouzon Syndrome: a Comprehensive Review

Crouzon syndrome is a rare genetic disorder with autosomal dominant inheritance. The underlying pathological process is premature synostosis of the cranial sutures with subsequent phenotypic alterations of the affected person. A review of the literature has been conducted in order to resume the overall characteristics of Crouzon syndrome such as craniomaxillofacial malformations, clinical features, dentoalveolar characteristics, aesthetic impairments, and psychological background, as well as, the different therapeutic procedures, which combine surgical and orthodontic interventions. Facial and functional malformations in individuals with Crouzon syndrome could be significantly improved after a series of surgical and orthodontic procedures in almost all cases. A multidisciplinary treatment approach would provide the best outcomes in affected patients.

Advantages of 3D ultrasound in the assessment of fetal abnormalities

Three-/four-dimensional (3D/4D) imaging enables a more detailed survey of the embryo and the fetus compared to two-dimensional (2D) ultrasound. The availability of several display modes and standardized examinations permits the demonstration of both the normal and abnormal fetal anatomy in controlled planes and rendered images from different angles. This allows the demonstration of even subtle fetal defects in an ideal sectional plane in a precisely rendered surface or transparent image viewed from an optimal angle. When counseling the parents, the rendered images can help them understand the severity of an existing malformation or, conversely, ensure them of the absence of any fetal abnormality. This is particularly useful in cases with an increased recurrence risk of a specific fetal malformation.

Prenatal ultrasound parameters in single-suture craniosynostosis

INTRODUCTION

Although single-suture craniosynostosis is diagnosed sporadically during pregnancy, timely referral is critical for its treatment. Additionally, craniosynostosis leads to increased maternofetal trauma during birth. In the Netherlands, 95% of pregnant women receive a standard ultrasound at around 20 weeks of gestation, potentially an ideal setting for detecting craniosynostosis prenatally. To enhance the prenatal detection of the metopic and the sagittal suture synostosis, we wished to identify new screening parameters.

MATERIALS AND METHODS

We retrospectively analyzed data of the 20-week anomaly scan in trigonocephaly patients (n = 41), scaphocephaly patients (n = 41), and matched controls (n = 82). We measured six different cranial dimensions, including head circumference, biparietal diameter, and occipito-frontal diameter, defining the cephalic index as the ratio between biparietal and occipito-frontal diameter.

RESULTS

Prenatal biometric measurements did not differ significantly between trigonocephaly patients and controls. Although significantly lower in scaphocephaly patients (0.76 versus 0.79; p = .000), the cephalic index by itself is not appropriate for screening at 20 weeks of gestation. Longitudinal analysis suggests that a deflection in BPD curve is found in scaphocephaly patients, starting at 20 weeks of gestation.

CONCLUSIONS

Prenatal biometric measurements do not differ significantly between trigonocephaly patients and controls. The CI is lower in scaphocephaly patients. A deflection in BPD curve should be followed by 3 D imaging of the cranial sutures.

Trans-Pacific tele-ultrasound image transmission of fetal central nervous system structures

OBJECTIVE

To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

METHODS

In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

RESULTS

The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI = 66.4-86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI = 70.0-80.8%) the scores of transmitted image were considered the same as the original.

CONCLUSION

We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.

Size of the anterior fontanelle: three-dimensional measurement of a key trait in human evolution

The anterior fontanelle (AF) is an integral element of the developing human infant craniofacial system. Consideration of the AF is crucial for assessing craniofacial growth, as altered development of this feature may indicate abnormal growth. Moreover, prolonged patency of the AF may represent a derived hominin feature. The AF is regarded as essential for fetal head molding during birth in humans, with deformation of the head during birth often necessary for successful delivery. However, the function of a patent AF among fossil hominins is unclear. Because the AF represents an important structure in both a clinical and evolutionary context, techniques for estimating the size of the AF must be accurate and reproducible. Therefore, we have developed a novel method for assessing surface area of the AF with the goal of creating a more accurate measure of this feature. In this study, we test the accuracy and repeatability of a novel three-dimensional (3D) method for assessing the size of the AF in human infants and compare the results obtained for surface area of the AF using the conventional and 3D methods.

The fetal profile line: a proposal for a sonographic reference line to classify forehead and mandible anomalies in the second and third trimester

OBJECTIVES

To test the fetal profile (FP) line, defined as the line that passes through the anterior border of the mandible and the nasion, as a reference line for forehead and mandible anomalies.

METHODS

Volumes of 248 normal and 24 pathological fetuses (16-36 and 19-37 weeks' gestation, respectively) were analysed retrospectively. When the FP line passes anteriorly, across or posteriorly to the frontal bone, this was defined as 'negative', 'zero' or 'positive', respectively. When the FP line was positive the distance (F distance) between the FP line and the frontal bone was measured.

RESULTS

No cases with a negative FP line were found in the normal fetuses. Before 27 weeks' gestation the FP line was always 'zero' except in one case. After 27 weeks' gestation the FP line was 'positive' in up to 25% (F distance (mean, range): 2.8, 2.1-3.6 mm). The FP line correctly identified 13 cases with retrognathia, 5 cases with frontal bossing and 3 cases with a sloping forehead.

CONCLUSION

Although large prospective studies are needed, the FP line may be a useful tool to detect second trimester profile anomalies such as retrognathia, sloping forehead and frontal bossing with the possibility of quantifying the latter.

Surface area measurement using rendered three-dimensional ultrasound imaging: an in-vitro phantom study

OBJECTIVE

Cranial sutures and fontanelles can be reliably demonstrated using three-dimensional (3D) ultrasound with rendering. Our objective was to assess the repeatability and validity of fontanelle surface area measurement on rendered 3D images.

METHODS

This was an in-vitro phantom validation study. Four holes, representing fontanelles, were cut on a flat vinyl tile. The phantom was scanned in a test-tank by two sonographers, at four different depths and using two different 3D sweep directions. The surface areas were measured on scan images and also directly from the phantom for comparison. Coefficients of variation (CVs), intraclass correlation coefficients (ICCs) and Bland-Altman plots were used for repeatability analysis. Validity was expressed as the percentage difference of the measured area from the true surface area.

RESULTS

Validity of measurement was satisfactory with a mean percentage difference of - 5.9% (median = - 3.5%). The 95% limits of agreement were - 23.9 to 12.1%, suggesting that random error is introduced during image generation and measurement. Repeatability of caliper placement on the same image was higher (intraobserver CV = 1.6%, ICC = 0.999) than for measurement of a newly generated scan image (intraobserver CV = 5.5%, ICC = 0.992). Reduced accuracy was noted for the smallest shape tested.

CONCLUSION

Surface area measurements on rendered 3D ultrasound images are accurate and reproducible in vitro.

Meningocele following aplasia of the occipital bone

We describe a first trimester female foetus with aplasia of the occipital bone allowing a meningocele without skin coverage to be formed. The pregnancy was terminated, and on later autopsy the brain appeared to be intact. The foetus carried an apparently balanced translocation 46,XX,t(3;9)(p21.3;q22.3) inherited from a normal father and grandfather.

3D and 4D sonography and magnetic resonance in the assessment of normal and abnormal CNS development: alternative or complementary

Advanced transvaginal neurosonography has revealed normal and abnormal intracranial morphology. Transvaginal three-dimensional (3D) sonography demonstrates bony structure, multiplanar analysis of inside detailed morphology, tomographic ultrasound imaging in any cutting sections, 3D sonoangiography and volume calculation of ventricles and/or intracranial lesions. Longitudinal assessment of normal and abnormal central nervous system (CNS) development is done by serial scanning. However, the transvaginal high-frequency approach has several limitations due to lack of penetration and cranial bone ossification with advanced gestational age. Magnetic resonance neuroimaging enabled observation of the whole intracranial cavity, brainstem and cortical gyral/sulcal development. On the other hand, neuro-sonography has advantages in detecting intracranial calcification, vascular abnormalities, intratumoral vascularity and bone dysplasia. Moreover, 3D ultrasound demonstrates extra CNS abnormalities, strongly associated with CNS abnormalities. Any less-invasive modalities can be used for a CNS anomaly screening scan and ultrasound is no doubt the first choice. Once CNS abnormality is suspected, it is suggested to use the different technologies according to what is looked for in each abnormal CNS case. Of course, MR and 3D ultrasound imaging should be complementary as well as alternative.

Three-dimensional multiplanar ultrasound is a valuable tool in the study of the fetal profile in the second trimester of pregnancy

OBJECTIVES

To evaluate the additional value of three-dimensional (3D) multiplanar ultrasound in the examination of the fetal profile.

METHODS

Two 3D volumes of the fetal head were obtained from 84 fetuses at 22 to 29 weeks' gestation. The volumes were taken starting at the midsagittal plane with the fetus facing the transducer. The success rate and acquisition time to obtain each volume and display the exact midsagittal plane by 3D multiplanar ultrasound were analyzed. The correction angles from the original two-dimensional (2D) profile view to the exact midsagittal plane were noted. Of six measurements, related to the fetal nose and jaws, the success rate and the intraobserver reproducibility between the 2D and the 3D multiplanar ultrasound were compared.

RESULTS

In 81 (96.4%) cases we succeeded in obtaining a profile volume, 70% of the volumes being obtained within 10 min. It was possible to define by multiplanar mode the exact midsagittal plane in less than 1 min. The mean rotation necessary to obtain the exact midsagittal plane with 3D multiplanar mode was significantly larger around the y-axis (11.9 degrees ) than around the z-axis (4.3 degrees ) of the fetus. For between 5 and 12% of the six measurements under investigation it was not possible to obtain values with 2D ultrasound. However, 3D ultrasound made these measurements possible in at least one volume. The intraobserver reproducibility was higher with 3D multiplanar ultrasound than with 2D ultrasound, this difference being statistically significant for five of the six measurements.

CONCLUSIONS

3D multiplanar ultrasound improves the topographic depiction of the midsagittal profile view, enables correct measurement of anatomical details and improves intraobserver reproducibility. 3D multiplanar ultrasound is a powerful instrument for investigating the fetal profile.

The frequency of metopism in Anatolian populations dated from the Neolithic to the first quarter of the 20th century

Metopism, which is defined as a condition in which the two pieces of the frontal bone fail to merge in early childhood, displays varying degrees of incidence. In this study, the variation of the frequency of metopism across historical periods is investigated on the skulls of 487 adults from 12 different Ancient Anatolian populations dated to various periods of history ranging from the Neolithic to the first quarter of the 20th century. In addition, the study also examines the relationship of metopism to sex and cranial form. It is revealed that the frequency of metopism showed a relative increase across time periods in Anatolia after the Neolithic Period, with the exception of the Cevizcioğlu Ciftliği population. However, no significant relationship was found between metopism and cranial form or sex. It is found that the frequency of metopism in Ancient Anatolia had a distribution range of 3.3-14.9%. This distribution shows that the inhabitants of Anatolia have a heterogeneous genetic make-up due to the geographical situation of Anatolia, which has been open to gene flow both in the past and at present.

Normal and abnormal development of the fetal anterior fontanelle: a three-dimensional ultrasound study

OBJECTIVES

To describe the methodology for correct visualization of the anterior fontanelle using three-dimensional ultrasound, to report its normal development during gestation, and to compare this with abnormal development.

METHODS

This was a cross-sectional prospective evaluation of development of the anterior fontanelle in a series of 78 normal fetuses and 47 fetuses with congenital anomalies between 12 and 38 weeks of gestation. The anterior fontanelle was visualized in a mid-sagittal view of the fetal head, preferably with a pocket of fluid between the fetal head and the uterine wall, to ensure an optimal acoustic window. Visualization using volume contrast imaging mode in the coronal plane (VCI-C) was preferred to static acquisition of three-dimensional (3D) volumes, as the former allows real-time evaluation of the 3D image. Anteroposterior and laterolateral diameters, perimeter and area of the fontanelle were measured offline, with the diameters normalized for biparietal diameter and the perimeter and area normalized for head circumference. The variables were then regressed against gestational age.

RESULTS

The best fitting regression model to describe the relationships between the fontanelle anteroposterior diameter and area and gestational age was a quadratic one, whereas a simple linear model fitted all remaining variables. All variables showed a positive or biphasic correlation with advancing gestational age, but a negative one after normalization for biparietal diameter or head circumference. Twenty of the 47 fetuses with abnormalities had abnormal (18 enlarged and two reduced) fontanelle dimensions, particularly those with chromosomal or non-chromosomal syndromes, primary or secondary cardiac overload, primary skeletal dysplasias or central nervous system malformations. Hydrops was not associated with abnormal fontanelle dimensions.

CONCLUSIONS

We have described the methodology to obtain correct visualization of the fetal anterior fontanelle. The actual size of the fontanelle increases during gestation, while its size in relation to the volume of the fetal head diminishes, possibly due to the rapid development of the brain hemispheres and the consequent outward growth of the calvarial bones. The fact that enlarged fontanelle dimensions may be associated with certain fetal abnormalities may be employed advantageously in the differential diagnosis of some syndromic conditions in utero.

Three-dimensional ultrasound in prenatal diagnosis

PURPOSE OF REVIEW

Several technological advances have greatly improved three-dimensional sonography, which have improved acquisition and display capabilities. This review describes these technical changes as well as current applications of 3D sonography in prenatal diagnosis.

RECENT FINDINGS

Recently published papers have emphasized the potential of getting a precise 'any plane of choice' from a three-dimensional volume, as a new way of scanning, based on the off-line analysis of a volume dataset. Surface mode has been used to demonstrate malformations and genetic diseases. The maximum rendering mode, which highlights bones, has great potential for imaging the nasal bones and the frontal bones with the metopic suture. Organ volume can be measured, but the utility of this in clinical practice remains to be determined. Three-dimensional ultrasound needs to be standardized.

SUMMARY

Three-dimensional ultrasonography is the most rapidly developing technique in fetal imaging. New features will permit the transition from the era of 'sonography in two-dimensional planes' to 'volume ultrasound'.

Frontomaxillary facial angle in fetuses with trisomy 13 at 11 + 0 to 13 + 6 weeks

OBJECTIVE

To investigate the frontomaxillary facial (FMF) angle in fetuses with trisomy 13 at 11 + 0 to 13 + 6 weeks of gestation.

METHODS

A three-dimensional (3D) volume of the fetal head was obtained before karyotyping at 11 + 0 to 13 + 6 weeks of gestation in 23 fetuses with trisomy 13. The FMF angle, defined as the angle between the upper surface of the maxilla and the frontal bone in a midsagittal view of the fetal face, was measured and compared to the angle in 500 chromosomally normal fetuses.

RESULTS

In 10 of 12 (83.3%) fetuses with trisomy 13 and holoprosencephaly, the FMF angle was above the 95(th) centile of the normal range. In the 11 fetuses with no holoprosencephaly, the FMF angle was not significantly different from normal. There was no significant difference in the FMF angle between the trisomy 13 fetuses with and without facial cleft.

CONCLUSIONS

In fetuses with trisomy 13, the FMF angle at 11 + 0 to 13 + 6 weeks of gestation is increased only in cases with associated holoprosencephaly.

Fetuses with Down syndrome have an enlarged anterior fontanelle in the second trimester of pregnancy

OBJECTIVE

Neonates with Down syndrome are known to have an enlarged anterior fontanelle. The aim of this study was to assess whether fetuses diagnosed with Down syndrome in the second trimester have larger anterior fontanelles in comparison with normal euploid fetuses.

METHODS

The study population included 13 fetuses with trisomy 21 and 26 normal euploid fetuses analyzed between the 19(th) and the 23(rd) weeks of gestation. The anterior fontanelle was assessed by three-dimensional ultrasound, with the midsagittal plane of the fetal head being the reference view for acquisition of the volume. Anteroposterior and laterolateral diameters, perimeter and area of the fontanelle were then measured offline; the diameters were normalized for biparietal diameter and the perimeter and area were normalized for head circumference. Non-parametric statistical analysis was used to compare the mean values of all variables in the two groups of fetuses. Intra- and interobserver variability were also assessed.

RESULTS

All variables except the fontanelle laterolateral diameter were significantly greater in Down syndrome fetuses than in controls, with anterior fontanelle perimeter/head circumference and fontanelle area/head circumference ratios showing the highest sensitivity for the detection of Down syndrome. Using a cut-off of 2.1 for the fontanelle area/head circumference ratio, the sensitivity and specificity for the detection of Down syndrome were 77% and 96%, respectively.

CONCLUSION

During the mid-trimester the dimensions of the anterior fontanelle are significantly increased in fetuses with Down syndrome in comparison with normal euploid fetuses. This finding may be of help in the detection of trisomy 21 at the time of the anomaly scan.

Transfrontal three-dimensional visualization of midline cerebral structures

OBJECTIVE

To compare sonographic visualization of midline cerebral structures obtained by two-dimensional (2D) imaging and three-dimensional (3D) multiplanar and volume contrast imaging in the coronal plane (VCI-C), with transfrontal 3D acquisition.

METHODS

Sixty consecutive healthy fetuses in vertex presentation at a mean gestational age of 24 (range, 20-33) weeks underwent 2D and 3D ultrasound examination. Sagittal cerebral planes were reconstructed using 3D acquisition from axial planes by multiplanar analysis and by VCI-C. The reconstructed midline images of both these techniques were compared with the midline structures visualized directly in the A-plane by transfrontal 3D acquisition using a sweep angle of 30 degrees . Measurement of the corpus callosum and cerebellar vermis and visualization of the fourth ventricle and the main vermian fissures were compared. The sharpness of the images was also assessed qualitatively. Mid-sagittal tomographic ultrasound imaging (TUI) was also performed. 3D planes were compared with 2D transfontanelle median planes obtained by transabdominal or, when required, transvaginal sonography.

RESULTS

The midline plane could be obtained in 88% of multiplanar, 82% of VCI-C and 87% of transfrontal analyses. Measurements of the corpus callosum and cerebellar vermis obtained by 3D median planes were highly correlated. The clearest and sharpest definition of midline structures was obtained with transfrontal acquisition. Primary and secondary fissures of the cerebellar vermis could be detected in 13-26% of multiplanar, 18-35% of VCI-C and 52-79% of transfrontal analyses. 2D visualization was superior or equal to the 3D transfrontal approach in all the parameters compared.

CONCLUSION

3D planes obtained from axial acquisitions are simpler and easier to display than are transfrontal ones. However, artifacts and acoustic shadowing are frequent in 3D axial acquisition and spatial resolution is better in the direct visualization transfrontal technique. If the standard examination includes a view of the fetal facial profile, a quick 3D acquisition through the frontal sutures provides direct visualization for assessment of the midline structures. We believe that this volumetric methodology could represent a step towards incorporating a comprehensive fetal neuroscan into routine targeted organ evaluation.

Assessment of the third-trimester fetus using 3-dimensional volumes: a pilot study

PURPOSE

To examine whether the third-trimester fetus can be assessed sonographically using 3-dimensional (3D) volume data sets.

METHODS

Twenty-seven consecutive third-trimester fetuses were evaluated. Fetuses were scanned using 2-dimensional (2D) imaging followed by 5 3D volume acquisitions. The initial scan was interpreted and reported based on the 2D images. The 3D volume data sets were independently reviewed offline several weeks later by 2 sonologists. Parameters evaluated included fetal presentation, placental location, amniotic fluid volume, fetal biometry including a calculation of estimated fetal weight, and major fetal anatomic structures. The result of the interpretation via 3D reconstruction of the volume from each of the 2 sonologists was compared with the original 2D sonography report.

RESULTS

Fetal presentation, amniotic fluid volume, and placental location with respect to the cervix were correctly identified 100% of the time by each sonologist. The estimated fetal weight was within 10% of the 2D estimate 89% (95% CI, 0.71-0.98) of the time for sonologist A and 96% (95% CI, 0.81-0.99) of the time for sonologist B. The majority of major anatomic landmarks were adequately seen by both sonologists.

CONCLUSION

Offline review of 3D volume data sets is a reliable method for determining fetal presentation, amniotic fluid volume, placental location, and estimating fetal weight in the third trimester.

How useful is 3D and 4D ultrasound in perinatal medicine?

AIM

The purpose of this paper is to review and analyze the published literature on the use of three-dimensional (3DUS) and four-dimensional (4DUS) ultrasound in perinatal medicine.

METHODS

We systematically searched Medline through PubMED (January 2000-January 2006), including EMBASE/Excerpta Medica database as well as the Cochrane Database of Systematic Reviews. The search terms used to identify clinical application of 3DUS and 4DUS studies in perinatal medicine were technical development, special features, and recommendation for fetal imaging, research on 3DUS or 4DUS, and the usage of invasive 3DUS or 4DUS procedures. The reference bibliographies of relevant books were also manually searched for supplementary citations. Inclusion criteria were as follows: (1) studies related to the use of 3DUS or 4DUS in perinatal medicine; (2) full text were available in English; (3) publication format of original scientific articles, case reports, editorials or literature reviews and chapters in the books.

RESULTS

Five hundred and seventy-five articles were identified, and among those, 438 were relevant to this review.

CONCLUSIONS

3DUS and 4DUS provided additional information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical utility of 3DUS and 4DUS for the diagnosis of congenital heart disease, central nervous system (CNS) anomalies and detection of fetal neurodevelopmental impairment assessed by abnormal behavior in high-risk fetuses.

Frontomaxillary facial angle at 11+0 to 13+6 weeks' gestation-reproducibility of measurements

OBJECTIVE

To assess the intra- and interobserver reproducibility in the measurement of the frontomaxillary facial (FMF) angle at 11+0 to 13+6 weeks' gestation and to investigate the effect of deviations from the exact mid-sagittal view on these measurements.

METHODS

Three-dimensional (3D) volumes of the fetal face were used by two operators to measure the FMF angle in 50 chromosomally normal and 50 trisomy 21 fetuses. The measurements were taken in the exact mid-sagittal view and repeated after lateral rotation of the head by 5 degrees, 10 degrees and 15 degrees away from the vertical position of the occipitofrontal diameter axis. Mean difference and 95% limits of agreement between paired measurements of FMF angle by the same and by two different sonographers were determined.

RESULTS

In the mid-sagittal plane the maxillary bone was rectangular shaped. Rotation away from this plane became easily recognizable because at a mean of 7 degrees (range, 4-10 degrees) the shape of the maxilla changed with the appearance of the zygomatic process of the maxilla and at a mean of 8 degrees (range, 4-12 degrees) the tip of the nose became invisible. In both the normal and trisomy 21 fetuses the FMF angle measured at 5-15 degrees was not significantly different from the one measured in the mid-sagittal plane. In 95% of the cases, the difference between paired measurements of the FMF angle by the same sonographer at the mid-sagittal plane was between -2.3 degrees and 3.0 degrees and at 15 degrees it was -1.0 degrees to 6.8 degrees. At the mid-sagittal plane, the difference in measurements between two sonographers was -3.1 to 3.0 degrees.

CONCLUSION

The landmarks that define the mid-sagittal plane of the fetal face are the tip of the nose and the rectangular shaped maxilla. Measurement of the FMF angle is highly reproducible.

Three- and four-dimensional ultrasonography for the structural and functional evaluation of the fetal face

Ultrasonographic examination of the fetal face can provide information that may lead to the diagnosis of anomalies in other organs or systems. Thus, the fetal face represents a "diagnostic window" for fetal diseases and syndromes. Three-dimensional ultrasonography (3DUS) improves the evaluation of anatomic fetal facial anomalies over what is possible by 2-dimensional ultrasonography (2DUS). Four-dimensional ultrasonography (4DUS), by adding the temporal component to the examination, allows visualization of facial expressions that might be useful in the study of fetal behavior and maternal-fetal bonding. In this article, we evaluate the potential of 3D/4DUS for the study of structural and functional development of the fetal face.

Intérêt de l’échographie 3D-4D en échographie fœtale et gynécologique : principes et indications

Three-dimensional ultrasound has become an essential tool for visualization of fetal structures in the past few years. The recent improvements in transducers and signal processing provide new information, particularly in obstetrics and gynecology sonography. The present paper will present the most recent advances in volume acquisition and presentation modes followed by results of fetal organ visualization in normal and abnormal cases as well as applications in gynecology.

Metopic suture in fetuses with Apert syndrome at 22-27 weeks of gestation

OBJECTIVES

To examine the possible association of skull deformity and the development of the cranial sutures in fetuses with Apert syndrome.

METHODS

Three-dimensional (3D) ultrasound was used to examine the metopic and coronal sutures in seven fetuses with Apert syndrome at 22-27 weeks of gestation. The gap between the frontal bones in the transverse plane of the head at the level of the cavum septi pellucidi was measured and compared to findings in 120 anatomically normal fetuses undergoing routine ultrasound examination at 16-32 weeks.

RESULTS

In the normal group, the gap between the frontal bones in the metopic suture at the level of the cavum septi pellucidi, decreased significantly with gestation from a mean of 2.2 mm (5th and 95th centiles: 1.5 mm and 2.9 mm) at 16 weeks to 0.9 mm (5th and 95th centiles: 0.3 mm and 1.6 mm) at 32 weeks. In the seven cases with Apert syndrome, two-dimensional ultrasound examination demonstrated the characteristic features of frontal bossing, depressed nasal bridge and bilateral syndactyly. On 3D examination there was complete closure of the coronal suture and a wide gap in the metopic suture (15-23 mm).

CONCLUSION

In normal fetuses, cranial bones are believed to grow in response to the centrifugal pressure from the expanding brain and proximity of the dura to the suture is critical in maintaining its patency. In Apert syndrome, the frontal bossing may be a mere consequence of a genetically predetermined premature closure of the coronal suture. Alternatively, there is a genetically predetermined deformation of the brain, which in turn, through differential stretch of the dura in the temporal and frontal regions, causes premature closure of the coronal suture and impaired closure of the metopic suture.

Three-dimensional sonographic description of abnormal metopic suture in second- and third-trimester fetuses

OBJECTIVE

To describe patterns of abnormal development of the metopic suture in association with fetal malformations during the second and third trimesters of pregnancy.

METHODS

This was a cross-sectional study of the frontal bones and metopic suture in 11 fetuses at 17-32 weeks of gestation. Cases were selected because there were obvious abnormalities in the metopic sutures. In each case, a malformation was detected by two-dimensional (2D) ultrasound and the abnormality of the metopic suture was detected and evaluated on three-dimensional (3D) ultrasound, using transparent maximum mode.

RESULTS

There were essentially four patterns of abnormality in the metopic suture: firstly, delayed development with a V- or Y-shaped open suture, which is found in normal fetuses at 12-16 weeks; secondly, a U-shaped open suture, presumably due to upward growth of the frontal bones with delayed closure; thirdly, premature closure of the suture, which is normally observed after 32 weeks; fourthly, the presence of additional bone between the frontal bones. Premature closure of the suture or additional bone between the frontal bones was observed in fetuses with holoprosencephaly and abnormalities of the corpus callosum, whereas the V-, Y- and U-shaped metopic sutures were observed in fetuses with facial defects involving the orbits, nasal bones, lip, palate and mandible, in the absence of holoprosencephaly and abnormal corpus callosum.

CONCLUSIONS

This preliminary study describes the pattern of possible abnormalities of the metopic suture and should stimulate further investigation to establish the prevalence and evolution of abnormal sutures as well as the incidence and pattern of other associated defects.