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1.
PLoS Genet ; 17(8): e1009695, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34411106

RESUMO

Facial morphology is highly variable, both within and among human populations, and a sizable portion of this variation is attributable to genetics. Previous genome scans have revealed more than 100 genetic loci associated with different aspects of normal-range facial variation. Most of these loci have been detected in Europeans, with few studies focusing on other ancestral groups. Consequently, the degree to which facial traits share a common genetic basis across diverse sets of humans remains largely unknown. We therefore investigated the genetic basis of facial morphology in an East African cohort. We applied an open-ended data-driven phenotyping approach to a sample of 2,595 3D facial images collected on Tanzanian children. This approach segments the face into hierarchically arranged, multivariate features that capture the shape variation after adjusting for age, sex, height, weight, facial size and population stratification. Genome scans of these multivariate shape phenotypes revealed significant (p < 2.5 × 10-8) signals at 20 loci, which were enriched for active chromatin elements in human cranial neural crest cells and embryonic craniofacial tissue, consistent with an early developmental origin of the facial variation. Two of these associations were in highly conserved regions showing craniofacial-specific enhancer activity during embryological development (5q31.1 and 12q21.31). Six of the 20 loci surpassed a stricter threshold accounting for multiple phenotypes with study-wide significance (p < 6.25 × 10-10). Cross-population comparisons indicated 10 association signals were shared with Europeans (seven sharing the same associated SNP), and facilitated fine-mapping of causal variants at previously reported loci. Taken together, these results may point to both shared and population-specific components to the genetic architecture of facial variation.


Assuntos
Grupo com Ancestrais do Continente Africano/genética , Grupo com Ancestrais do Continente Europeu/genética , Face/anatomia & histologia , Estudo de Associação Genômica Ampla/métodos , Locos de Características Quantitativas , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Polimorfismo de Nucleotídeo Único , Tanzânia , Adulto Jovem
2.
Orthod Craniofac Res ; 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34310057

RESUMO

OBJECTIVES: Palatal shape contains a lot of information that is of clinical interest. Moreover, palatal shape analysis can be used to guide or evaluate orthodontic treatments. A statistical shape model (SSM) is a tool that, by means of dimensionality reduction, aims at compactly modeling the variance of complex shapes for efficient analysis. In this report, we evaluate several competing approaches to constructing SSMs for the human palate. SETTING AND SAMPLE POPULATION: This study used a sample comprising digitized 3D maxillary dental casts from 1,324 individuals. MATERIALS AND METHODS: Principal component analysis (PCA) and autoencoders (AE) are popular approaches to construct SSMs. PCA is a dimension reduction technique that provides a compact description of shapes by uncorrelated variables. AEs are situated in the field of deep learning and provide a non-linear framework for dimension reduction. This work introduces the singular autoencoder (SAE), a hybrid approach that combines the most important properties of PCA and AEs. We assess the performance of the SAE using standard evaluation tools for SSMs, including accuracy, generalization, and specificity. RESULTS: We found that the SAE obtains equivalent results to PCA and AEs for all evaluation metrics. SAE scores were found to be uncorrelated and provided an optimally compact representation of the shapes. CONCLUSION: We conclude that the SAE is a promising tool for 3D palatal shape analysis, which effectively combines the power of PCA with the flexibility of deep learning. This opens future AI driven applications of shape analysis in orthodontics and other related clinical disciplines.

3.
Orthod Craniofac Res ; 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34169645

RESUMO

OBJECTIVES: To develop and evaluate a geometric deep-learning network to automatically place seven palatal landmarks on digitized maxillary dental casts. SETTINGS AND SAMPLE POPULATION: The sample comprised individuals with permanent dentition of various ethnicities. The network was trained from manual landmark annotations on 732 dental casts and evaluated on 104 dental casts. MATERIALS AND METHODS: A geometric deep-learning network was developed to hierarchically learn features from point-clouds representing the 3D surface of each cast. These features predict the locations of seven palatal landmarks. RESULTS: Repeat-measurement reliability was <0.3 mm for all landmarks on all casts. Accuracy is promising. The proportion of test subjects with errors less than 2 mm was between 0.93 and 0.68, depending on the landmark. Unusually shaped and large palates generate the highest errors. There was no evidence for a difference in mean palatal shape estimated from manual compared to the automatic landmarking. The automatic landmarking reduces sample variation around the mean and reduces measurements of palatal size. CONCLUSIONS: The automatic landmarking method shows excellent repeatability and promising accuracy, which can streamline patient assessment and research studies. However, landmark indications should be subject to visual quality control.

4.
Eur J Orthod ; 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34180974

RESUMO

OBJECTIVE: Quantification and visualization of the location and magnitude of facial asymmetry is important for diagnosis and treatment planning. The objective of this study was to analyze the asymmetric features of the face for skeletal Class III patients using spatially-dense geometric morphometrics. METHODS: Three-dimensional facial images were obtained for 86 skeletal Class III patients. About 7160 uniformly sampled quasi-landmarks were automatically identified on each face using template mapping technique. The pointwise surface-to-surface distance between original and mirror face was measured and visualized for the whole face after robust Procrustes superimposition. The degree of overall asymmetry in an individual was scored using a root-mean-squared-error. Automatic partitioning of the face was obtained, and the severity of the asymmetry compared among seven facial regions. RESULTS: Facial asymmetry was mainly located on, but not limited to, the lower two-thirds of the face in skeletal Class III patients. The lower cheek and nose asymmetry were detected to have more extensive and of a greater magnitude of asymmetry than other facial anatomical regions but with various individual variations. The overall facial asymmetry index and the regional facial asymmetry indices were higher in males and patients with chin deviation. CONCLUSIONS: Soft tissue asymmetry is predominately presented in the lower-third of the face in skeletal Class III patients and with various variations on other facial anatomical regions. Morphometric techniques and computer intensive analysis have allowed sophisticated quantification and visualization of the pointwise asymmetry on the full face.

5.
Sci Rep ; 11(1): 12175, 2021 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-34108542

RESUMO

Craniofacial dysmorphism is associated with thousands of genetic and environmental disorders. Delineation of salient facial characteristics can guide clinicians towards a correct clinical diagnosis and understanding the pathogenesis of the disorder. Abnormal facial shape might require craniofacial surgical intervention, with the restoration of normal shape an important surgical outcome. Facial anthropometric growth curves or standards of single inter-landmark measurements have traditionally supported assessments of normal and abnormal facial shape, for both clinical and research applications. However, these fail to capture the full complexity of facial shape. With the increasing availability of 3D photographs, methods of assessment that take advantage of the rich information contained in such images are needed. In this article we derive and present open-source three-dimensional (3D) growth curves of the human face. These are sequences of age and sex-specific expected 3D facial shapes and statistical models of the variation around the expected shape, derived from 5443 3D images. We demonstrate the use of these growth curves for assessing patients and show that they identify normal and abnormal facial morphology independent from age-specific facial features. 3D growth curves can facilitate use of state-of-the-art 3D facial shape assessment by the broader clinical and biomedical research community. This advance in phenotype description will support clinical diagnosis and the understanding of disease pathogenesis including genotype-phenotype relations.


Assuntos
Anormalidades Múltiplas/patologia , Anormalidades Craniofaciais/patologia , Face/patologia , Imageamento Tridimensional/métodos , Modelos Estatísticos , Atrofia Muscular/patologia , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antropometria , Estudos de Casos e Controles , Criança , Pré-Escolar , Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/metabolismo , Face/anormalidades , Feminino , Seguimentos , Gráficos de Crescimento , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , Fenótipo , Prognóstico , Adulto Jovem
6.
Comput Methods Programs Biomed ; 205: 106093, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33882417

RESUMO

Background and Objective; Genetic risk factors for childhood cancer may also influence facial morphology. 3D photography can be used in the recognition of differences in face shape among individuals. In previous research, 3D facial photography was used to identify increased facial asymmetry and greater deviation from normal facial morphology in a group of individuals with distinct morphological features who had childhood cancer compared to healthy controls. In this study, we aim to determine whether there is a difference in facial morphology between children with cancer without previously selected morphological features and healthy controls, detected with 3D facial photography. METHODS: Facial 3D photographic images were obtained of children with a newly diagnosed malignancy. The resulting sample comprised 13 different cancer types. Patients were excluded if they had a known genetic cause of the cancer. Patients were compared to healthy controls, matched for sex, age and ethnic background. The degree of asymmetry and overall deviation of an individual's face from an age and sex typical control face were measured. RESULTS: A total of 163 patients of European descent were included. No significant difference in asymmetry between patients and controls could be identified. On average, patients deviated more from an age and sex typical face than the controls. CONCLUSION: This study shows that children with cancer deviate more than controls, possibly suggesting a higher prevalence of genetic anomalies within this group. The results suggest that this is not sufficient to discriminate patients from controls. Further research is necessary to explore the patterns of individual variation among the overall deviation of patients and controls.


Assuntos
Imageamento Tridimensional , Neoplasias , Criança , Face , Assimetria Facial/diagnóstico por imagem , Humanos , Fotografação
7.
Sci Rep ; 11(1): 748, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33436952

RESUMO

The contribution of low-frequency variants to the genetic architecture of normal-range facial traits is unknown. We studied the influence of low-frequency coding variants (MAF < 1%) in 8091 genes on multi-dimensional facial shape phenotypes in a European cohort of 2329 healthy individuals. Using three-dimensional images, we partitioned the full face into 31 hierarchically arranged segments to model facial morphology at multiple levels, and generated multi-dimensional phenotypes representing the shape variation within each segment. We used MultiSKAT, a multivariate kernel regression approach to scan the exome for face-associated low-frequency variants in a gene-based manner. After accounting for multiple tests, seven genes (AR, CARS2, FTSJ1, HFE, LTB4R, TELO2, NECTIN1) were significantly associated with shape variation of the cheek, chin, nose and mouth areas. These genes displayed a wide range of phenotypic effects, with some impacting the full face and others affecting localized regions. The missense variant rs142863092 in NECTIN1 had a significant effect on chin morphology and was predicted bioinformatically to have a deleterious effect on protein function. Notably, NECTIN1 is an established craniofacial gene that underlies a human syndrome that includes a mandibular phenotype. We further showed that nectin1a mutations can affect zebrafish craniofacial development, with the size and shape of the mandibular cartilage altered in mutant animals. Findings from this study expanded our understanding of the genetic basis of normal-range facial shape by highlighting the role of low-frequency coding variants in several novel genes.


Assuntos
Grupo com Ancestrais do Continente Europeu/genética , Face/anatomia & histologia , Nectinas/genética , Fenótipo , Polimorfismo de Nucleotídeo Único , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Adulto Jovem , Peixe-Zebra
8.
J Shoulder Elbow Surg ; 30(5): 1095-1106, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32822879

RESUMO

HYPOTHESIS AND BACKGROUND: Rotator cuff tear arthropathy (RCTA) is a pathology characterized by a massive rotator cuff tear combined with acromiohumeral and/or glenohumeral arthritis. The severity of RCTA can be staged according to the Hamada classification. Why RCTA develops in some patients is unknown. Furthermore, in RCTA patients, distinctly different articular damage patterns can develop on the glenoid side as categorized by the Sirveaux classification (glenoid erosion). The goal of this study was to determine whether an association exists between scapular anatomy and RCTA and different severity stages of RCTA, as well as the associated glenoid erosion types. METHODS: A statistical shape model of the scapula was constructed from a data set of 110 computed tomography scans using principal component analysis. Sixty-six patients with degenerative rotator cuff pathology formed the control group. The computed tomography scan images of 89 patients with RCTA were included and grouped according to the Hamada and Sirveaux classifications. A complete 3-dimensional scapular bone model was created, and statistical shape model reconstruction was performed. Next, automated 3-dimensional measurements of glenoid version and inclination, scapular offset, the critical shoulder angle (CSA), the posterior acromial slope (PAS), and the lateral acromial angle (LAA) were performed. All measurements were then compared between controls and RCTA patients. RESULTS: The control group had a median of 7° of retroversion (variance, 16°), 8° of superior inclination (variance, 19°), and 106 mm of scapular offset (variance, 58 mm). The median CSA, PAS, and LAA were 30° (variance, 14°), 65° (variance, 60°), and 90° (variance, 17°), respectively. In terms of inclination, version, scapular offset, and the PAS, we found no statistically significant differences between the RCTA and control groups. For RCTA patients, the median CSA and median LAA were 32° (P ≤ .01) and 86° (P ≤ .01), respectively. For all investigated parameters, we did not find any significant difference between the different stages of RCTA. Patients with type E3 erosion had a different pre-arthropathy anatomy with increased retroversion (12°, P = .006), an increased CSA (40°, P ≤ .001), and a reduced LAA (79°, P ≤ .001). DISCUSSION: Our results seem to indicate that a 4° more inferiorly tilted and 2° more laterally extended acromion is associated with RCTA. RCTA patients in whom type E3 erosion develops have a distinct pre-arthropathy scapular anatomy with a more laterally extended and more inferiorly tilted acromion and a more retroverted glenoid in comparison with RCTA patients with no erosion. The pre-arthropathy scapular anatomy does not seem to differ between patients with different stages of RCTA.


Assuntos
Artropatias , Osteoartrite , Lesões do Manguito Rotador , Artropatia de Ruptura do Manguito Rotador , Articulação do Ombro , Humanos , Lesões do Manguito Rotador/diagnóstico por imagem , Escápula/diagnóstico por imagem , Articulação do Ombro/diagnóstico por imagem
9.
Plast Reconstr Surg Glob Open ; 8(5): e2847, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33154878

RESUMO

Three-dimensional (3D) photography is becoming widely used in plastic surgery. It provides an accurate and reproducible record of the facial surface anatomy and could be a versatile tool for treatment planning and assessment. However, the existing software tools available for the assessment of 3D facial imaging often give highly misleading results. The goal of this special topic article is to give clinicians an insight into methods of 3D image assessment and explain the reasons why results may be misleading. We point toward the advantages of an alternative approach using "nonrigid surface registration" for the comparison of pre- and postsurgical images. This approach is compared with the regular rigid surface registration, and this is illustrated by the assessment of a child with Crouzon syndrome before and after LeFort III osteotomy and distraction. Findings of the standard method imply that changes have occurred that are anatomically not possible, whereas the alternative approach indicates realistic changes. Furthermore, we demonstrate an exciting capacity of 3D image analysis to construct reference populations of normal head size and shape. These can be used to assess the parts of the head that are normal and abnormal pre- and posttreatment of the same child. We conclude that, while 3D image analysis has great potential in surgical assessment, existing software does not always give an adequate assessment. Collaboration among surgeons and engineering and computer science specialists should be encouraged. This way, more comprehensive and accurate techniques in patient assessment and surgical planning can be developed and applied in clinical practice.

10.
Pediatr Dent ; 42(4): 315-320, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32847672

RESUMO

Purpose: The purpose of this study was to characterize the facial morphology of Chinese children with hypohidrotic ectodermal dysplasia (HED) and quantify facial changes after prosthetic treatment. Methods: 3-D facial images of 12 HED children were taken and their facial morphology was compared against 28 healthy controls. Facial changes due to denture placement were also quantified. Group differences were quantified and visualized by superimposing the average faces with robust Procrustes superimposition. Partial least square regression was used to investigate the effects of group membership (HED or controls, pre- and posttreatment) on facial morphology. Results: HED patients had a more prominent forehead, depressed nasal region, depressed zygomatic zone, flat cheeks, and protuberant lips and chin compared with controls. The strongest differences were localized in the middle and lower face, especially in the cheeks and zygomatic and chin regions (P<0.05). Pre- and post-treatment comparisons showed the chin retruded (P<0.05). Statistical facial differences between the posttreatment patients and the controls were localized in the perinasal area and submental region (P<0.05). Conclusions: The facial morphology of Chinese children with hypohidrotic ectodermal dysplasia differs significantly from healthy children, creating a more concave facial profile. Posttreatment facial changes provide a better understanding of dentures' role in improving facial appearance.


Assuntos
Displasia Ectodérmica Anidrótica Tipo 1 , Displasia Ectodérmica , Criança , Dentaduras , Humanos , Imageamento Tridimensional
11.
Comput Methods Biomech Biomed Engin ; 23(13): 1026-1033, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32619099

RESUMO

Treatment of large acetabular defects and discontinuities remains challenging and relies on the accurate restoration of the native anatomy of the patient. This study introduces and validates a statistical shape model for the reconstruction of acetabular discontinuities with severe bone loss through a two-sided Markov Chain Monte Carlo reconstruction method. The performance of the reconstruction algorithm was evaluated using leave-one-out cross-validation in three defect types with varying severity as well as severe defects with discontinuities. The two-sided reconstruction method was compared to a one-sided methodology. Although, reconstruction errors increased with defect size and this increase was most pronounced for pelvic discontinuities, the two-sided reconstruction method was able to reconstruct the native anatomy with higher accuracy than the one-sided reconstruction method. These findings can improve the preoperative planning and custom implant design in patients with large pelvic defects, both with and without discontinuities.


Assuntos
Modelos Anatômicos , Modelos Estatísticos , Pelve/anormalidades , Pelve/cirurgia , Procedimentos Cirúrgicos Reconstrutivos , Acetábulo/cirurgia , Algoritmos , Feminino , Humanos , Masculino , Próteses e Implantes , Reprodutibilidade dos Testes
12.
BMC Oral Health ; 20(1): 117, 2020 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-32299402

RESUMO

BACKGROUND: A functional appliance is commonly used to optimize the development of the facial skeleton in the treatment of Class II malocclusion. Recent three-dimensional(3D) image-based analysis offers numerous advantages in quantitative measurement and visualization in orthodontics. The aim of this study was to localize in 3D the skeletal effect produced by the Herbst appliance on the mandible using the geometric morphometric technique. METHODS: Twenty patients treated with a Herbst appliance and subsequent fixed appliances were included. Cone-beam computed tomography (CBCT) images were taken before treatment (T1), 8 weeks after Herbst appliance removal (T2), and after subsequent fixed appliance treatment (T3). Spatially dense morphometric techniques were used to establish the corresponding points of the mandible. The mandibular morphological changes from T1-T2, T2-T3, and T1-T3 were calculated for each patient by superimposing two mandibular models at two time points with robust Procrustes superimposition. These changes were then compared to the morphological changes estimated from normative mandibular growth curves over the same period. The proportion of cases exceeding the growth expression for controls was compared to a normal population using a one tailed binomial test. RESULTS: Approximately 1.5-2 mm greater condylar changes and 0.5 mm greater changes in the chin occurred from Tl to T2. This effect lasted until the completion of treatment (T1-T3), but there was no obvious skeletal effect during the orthodontic phase (T2-T3). Approximately 40-50% of the patient sample exceeded condylar growth by > 1.5 mm compared to untreated controls (p < .05). However, changes at the chin were not statistically significant. CONCLUSIONS: The principal skeletal effect of Herbst appliance treatment was additional increase in condylar length for about half of the sample. This inconsistency may relate to the degree of mandibular growth suppression associated with a specific malocclusion.


Assuntos
Má Oclusão Classe II de Angle/diagnóstico por imagem , Mandíbula/diagnóstico por imagem , Aparelhos Ortodônticos Funcionais , Adolescente , Cefalometria , Criança , Estudos Transversais , Feminino , Humanos , Masculino , Má Oclusão Classe II de Angle/terapia , Estudos Retrospectivos
13.
Forensic Sci Int ; 299: 239.e1-239.e9, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31053243

RESUMO

OBJECTIVES: The aim of the present study was to use Fourier analysis to quantify and study age-related changes in midsagittal facial profile. MATERIALS AND METHODS: Midsagittal facial profiles were extracted as lists of x and y coordinates from 125 pairs of 3D facial scans captured at an average of 10.5 years apart for adult Japanese males aged 23-52 years. These were categorized into three 10-year-long age groups. Files of x and y coordinates underwent Fourier analysis at 30 harmonic levels. Paired t-tests were used to determine statistical significance of differences across corresponding harmonic coefficients. Mean harmonic coefficients were used to construct mean pre and post ageing profiles for each age group for qualitative comparisons. RESULTS: Full detail of facial profile was described by the first 20 harmonics. With increasing age, there was a trend of longitudinal changes involving more midsagittal shape features with increased magnitudes. However, all changes were lower than 1 mm. CONCLUSIONS: Fourier analysis is a useful morphometric approach to quantify age-related midsagittal facial changes. The small variations in the study groups prompt for testing Fourier analysis on the elderly and on other parasagittal and transverse facial features.


Assuntos
Envelhecimento , Análise de Fourier , Desenvolvimento Maxilofacial , Adulto , Grupo com Ancestrais do Continente Asiático , Ciências Forenses , Humanos , Imageamento Tridimensional , Japão , Estudos Longitudinais , Pessoa de Meia-Idade , Fotografação , Reprodutibilidade dos Testes , Adulto Jovem
14.
Sci Rep ; 9(1): 6085, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30988365

RESUMO

Dense surface registration, commonly used in computer science, could aid the biological sciences in accurate and comprehensive quantification of biological phenotypes. However, few toolboxes exist that are openly available, non-expert friendly, and validated in a way relevant to biologists. Here, we report a customizable toolbox for reproducible high-throughput dense phenotyping of 3D images, specifically geared towards biological use. Given a target image, a template is first oriented, repositioned, and scaled to the target during a scaled rigid registration step, then transformed further to fit the specific shape of the target using a non-rigid transformation. As validation, we use n = 41 3D facial images to demonstrate that the MeshMonk registration is accurate, with 1.26 mm average error, across 19 landmarks, between placements from manual observers and using the MeshMonk toolbox. We also report no variation in landmark position or centroid size significantly attributable to landmarking method used. Though validated using 19 landmarks, the MeshMonk toolbox produces a dense mesh of vertices across the entire surface, thus facilitating more comprehensive investigations of 3D shape variation. This expansion opens up exciting avenues of study in assessing biological shapes to better understand their phenotypic variation, genetic and developmental underpinnings, and evolutionary history.

15.
J Anat ; 234(5): 709-717, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30834524

RESUMO

The present study investigates how sexual dimorphism in the human mandible develops in three-dimensionally during adolescence. A cross-sectional sample of mandibular meshes of 268 males and 386 females, aged between 8.5 and 19.5 years of age, were derived from cone beam computed tomography and were analysed using geometric morphometric methods. Growth trajectories of the mandible in males and females were modelled separately using a recently developed non-linear kernel regression framework. Growth rate and direction at a dense array of points all over the mandibular surface were visualized within each group and compared between groups. We found that mandibular sexual dimorphism already exists at 9 years of age, but this is mostly in size not in shape. The differential growth rate and duration between the sexes during pubertal growth largely explained by adult sexual dimorphism: the growth direction in both males and females is similar but the male mandible changed more quickly and over a longer period than the female mandible, where the growth rate peaked and declined earlier. This results in increasing dimorphism in form, which is evident in both size and shape. The development of dimorphic features, concentrated in the chin and ramus, were further visualized. The dense morphometric approach provides detailed three-dimensional quantitative assessment of the development of sexual dimorphism of the mandible.


Assuntos
Mandíbula/crescimento & desenvolvimento , Caracteres Sexuais , Adolescente , Criança , Estudos Transversais , Feminino , Humanos , Imageamento Tridimensional , Masculino , Mandíbula/anatomia & histologia , Análise de Componente Principal , Adulto Jovem
16.
Dentomaxillofac Radiol ; 48(2): 20180261, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30379569

RESUMO

OBJECTIVES:: To propose a reliable and practical method for automatically segmenting the mandible from CBCT images. METHODS:: The marker-based watershed transform is a region-growing approach that dilates or "floods" predefined markers onto a height map whose ridges denote object boundaries. We applied this method to segment the mandible from the rest of the CBCT image. The height map was generated to enhance the sharp decreases of intensity at the mandible/tissue border and suppress noise by computing the intensity gradient image of the CBCT itself. Two sets of markers, "mandible" and "background" were automatically placed inside and outside the mandible, respectively in a novel image using image registration. The watershed transform flooded the gradient image by dilating the markers simultaneously until colliding at watershed lines, estimating the mandible boundary. CBCT images of 20 adolescent subjects were chosen as test cases. Segmentation accuracy of the proposed method was evaluated by measuring overlap (Dice similarity coefficient) and boundary agreement against a well-accepted interactive segmentation method described in the literature. RESULTS:: The Dice similarity coefficient was 0.97 ± 0.01 (mean ± SD), indicating almost complete overlap between the automatically and the interactively segmented mandibles. Boundary deviations were predominantly under 1 mm for most of the mandibular surfaces. The errors were mostly from bones around partially erupted wisdom teeth, the condyles and the dental enamels, which had minimal impact on the overall morphology of the mandible. CONCLUSIONS:: The marker-based watershed transform method produces segmentation accuracy comparable to the well-accepted interactive segmentation approach.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Mandíbula , Tomografia Computadorizada de Feixe Cônico Espiral , Adolescente , Algoritmos , Animais , Biomarcadores , Gatos , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Mandíbula/diagnóstico por imagem , Dente Serotino
18.
Forensic Sci Int ; 286: 61-69, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29567544

RESUMO

3D facial images are becoming increasingly common. They provide more information about facial form than their 2D counterparts and will be useful in future forensic applications. These include age estimation and predicting changes in appearance of missing persons (synthetic growth). We present a framework for both age estimation and synthetic growth of children and adolescents from 3D photographs. Age estimation accuracy was substantially better than for existing approaches (mean absolute error=1.19 years). Our synthetically 'grown' images were compared to actual longitudinal images of the same cases. On average 75% of the head overall and 85% of the face were predicted correctly to within three millimetres. We find that our approach is most suitable for ageing children from late childhood into adolescence. The work can be improved in the future by modelling skin colouring and taking account of other factors that influence face shape such as BMI.


Assuntos
Determinação da Idade pelo Esqueleto/métodos , Envelhecimento/fisiologia , Face/anatomia & histologia , Face/fisiologia , Imageamento Tridimensional , Fotografação , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Antropologia Forense , Humanos , Lactente , Recém-Nascido , Masculino , Estatística como Assunto
19.
Sci Rep ; 8(1): 4771, 2018 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-29556038

RESUMO

Many disorders present with characteristic abnormalities of the craniofacial complex. Precise descriptions of how and when these abnormalities emerge and change during childhood and adolescence can inform our understanding of their underlying pathology and facilitate diagnosis from craniofacial shape. In this paper we develop a framework for analysing how anatomical differences between populations emerge and change over time, and for binary group classification that adapts to the age of each participant. As a proxy for a disease-control comparison we use a database of 3D photographs of normally developing boys and girls to examine emerging sex-differences. Essentially we define 3D craniofacial 'growth curves' for each sex. Differences in the forehead, upper lip, chin and nose emerge primarily from different growth rates between the groups, whereas differences in the buccal region involve different growth directions. Differences in the forehead, buccal region and chin are evident before puberty, challenging the view that sex differences result from pubertal hormone levels. Classification accuracy was best for older children. This paper represents a significant methodological advance for the study of facial differences between growing populations and comprehensively describes developing craniofacial sex differences.


Assuntos
Desenvolvimento Maxilofacial , Caracteres Sexuais , Crânio/crescimento & desenvolvimento , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Modelos Estatísticos , Análise de Regressão
20.
JAMA Pediatr ; 171(8): 771-780, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28586842

RESUMO

Importance: Children who receive a diagnosis of fetal alcohol spectrum disorder may have a characteristic facial appearance in addition to neurodevelopmental impairment. It is not well understood whether there is a gradient of facial characteristics of children who did not receive a diagnosis of fetal alcohol spectrum disorder but who were exposed to a range of common drinking patterns during pregnancy. Objective: To examine the association between dose, frequency, and timing of prenatal alcohol exposure and craniofacial phenotype in 12-month-old children. Design, Setting, and Participants: A prospective cohort study was performed from January 1, 2011, to December 30, 2014, among mothers recruited in the first trimester of pregnancy from low-risk, public maternity clinics in metropolitan Melbourne, Australia. A total of 415 white children were included in this analysis of 3-dimensional craniofacial images taken at 12 months of age. Analysis was performed with objective, holistic craniofacial phenotyping using dense surface models of the face and head. Partial least square regression models included covariates known to affect craniofacial shape. Exposures: Low, moderate to high, or binge-level alcohol exposure in the first trimester or throughout pregnancy. Main Outcomes and Measures: Anatomical differences in global and regional craniofacial shape between children of women who abstained from alcohol during pregnancy and children with varying levels of prenatal alcohol exposure. Results: Of the 415 children in the study (195 girls and 220 boys; mean [SD] age, 363.0 [8.3] days), a consistent association between craniofacial shape and prenatal alcohol exposure was observed at almost any level regardless of whether exposure occurred only in the first trimester or throughout pregnancy. Regions of difference were concentrated around the midface, nose, lips, and eyes. Directional visualization showed that these differences corresponded to general recession of the midface and superior displacement of the nose, especially the tip of the nose, indicating shortening of the nose and upturning of the nose tip. Differences were most pronounced between groups with no exposure and groups with low exposure in the first trimester (forehead), moderate to high exposure in the first trimester (eyes, midface, chin, and parietal region), and binge-level exposure in the first trimester (chin). Conclusions and Relevance: Prenatal alcohol exposure, even at low levels, can influence craniofacial development. Although the clinical significance of these findings is yet to be determined, they support the conclusion that for women who are or may become pregnant, avoiding alcohol is the safest option.


Assuntos
Consumo Excessivo de Bebidas Alcoólicas/patologia , Anormalidades Craniofaciais/induzido quimicamente , Anormalidades Craniofaciais/diagnóstico por imagem , Transtornos do Espectro Alcoólico Fetal/patologia , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Austrália , Estudos de Coortes , Anormalidades Craniofaciais/patologia , Facies , Feminino , Humanos , Lactente , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal/patologia , Prevalência , Estudos Prospectivos , Crânio/anormalidades , Tomografia Computadorizada por Raios X
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