OBJECTIVES: Facial directional asymmetry research, including age-related changes, is crucial for the evaluation of treatment of craniofacial malformations/trauma in orthodontics, facial surgery and forensic sciences. The aim was to describe facial directional asymmetry (DA) in different age categories of adults using 3D methods. According to our hypothesis, facial shape DA (1) depends on sex; (2) differs among age groups; and (3) has wider variability in older age. MATERIAL AND METHODS: A cross-sectional sample of healthy Czech adults without craniofacial trauma or anomalies consisted of 300 3D facial models (151 females). The age-range in the study was between 20-80 years. The shape asymmetry of 28 3D landmarks was evaluated using geometric morphometrics and multivariate statistics. RESULTS: The manifestation of DA was similar in both sexes and in each age category; however, there were some statistical differences. In contrast to the ideal symmetrical face, the mean asymmetrical faces tended to create a slightly bent "C" shape of the midline. Therefore, the upper face was rotated slightly clockwise and the lower face counter-clockwise. The right eye was located slightly higher, with the nasal tip and mandibular region tilting to the left. Sex differences in facial DA were significant before the age of 40. DA was more significant in the youngest males than in the oldest, while the women's DA did not change. CONCLUSIONS: The DA patterns were similar in both sexes and in all age categories (a slightly bent C shape of the midline); however, some significant local differences between male age groups were found. A significantly more pronounced asymmetry compared to other age groups was found only in the youngest males from 20 to 40 years. Moreover, significant sexual dimorphism of DA rapidly decreased after middle age, likely caused by the same age-related changes of the face during aging.
- MeSH
- Facial Asymmetry * etiology MeSH
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Nose MeSH
- Sex Characteristics MeSH
- Cross-Sectional Studies MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Imaging, Three-Dimensional * MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Three-dimensional facial images are becoming more and more widespread. As such images provide more information about facial morphology than 2D imagery, they show great promise for use in future forensic applications, including age estimation and verification. This paper proposes an approach using random forests, a machine learning method, to develop and test models for classification of legal age thresholds (15 years and 18 years) using 3D facial landmarks. Our approach was developed on a set of 3D facial scans from 394 Czech individuals (194 males and 200 females) aged between 10 and 25 years. The dataset was retrieved from a sizable database of Central European faces - The FIDENTIS 3D Face Database. Three main types of input variables were processed using random forests: I) shape (size-invariant) coordinates of 3D landmarks, II) size and shape coordinates of 3D landmarks, and III) inter-landmark distances, angles and indices. The performance rates for the combinations of variables and age threshold were expressed in terms of sensitivity and specificity. The overall accuracy rates varied from 71.4%-91.5% (when the male and female samples were pooled). In general, higher accuracy was achieved for the age limit of 18 years than for 15 years. Whereas size-variant variables showed a better performance rate for the age limit of 15 years, the size-invariant variables (i.e., shape variables) were better for classifying individuals under 18 years. The verification models grounded on traditional variables (distances, angles, indices) yielded consistently higher performance rates on females than on males, whereas the inverse trend was observed for the models built on 3D coordinates. The results indicate that age verification based on 3D facial data with processing by the random forests method has high potential for further forensic or biometric applications.
- MeSH
- Anatomic Landmarks * MeSH
- Child MeSH
- Adult MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Face anatomy & histology MeSH
- Image Processing, Computer-Assisted MeSH
- Cross-Sectional Studies MeSH
- Machine Learning * MeSH
- Age Determination by Skeleton methods MeSH
- Imaging, Three-Dimensional * MeSH
- Check Tag
- Child MeSH
- Adult MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
The virtual approach in physical and forensic anthropology is increasingly used to further analyze human remains, but also to propose new didactic means for visualization and dissemination of scientific results. Computerized facial approximation (FA) offers an alternative to manual methods, but usually requires a complete facial skeleton to allow for the estimation of the facial appearance of an individual. This paper presents the case of Tycho Brahe, Danish astronomer born during the XVIth century, whose remains were reanalyzed at the occasion of a short exhumation in 2010. Cranial remains of Brahe were poorly preserved, with only a partial facial skeleton, and virtual anthropology tools were used to estimate the missing parts of his skull. This 3D restoration was followed by a FA using TIVMI-AFA3D, subsequently textured with graphic tools. The result provided an interesting estimate that was compared with portraits of the astronomer. The impact of the missing data estimation was investigated by performing FAs on 10 complete test subjects and the same 10 subjects after cropping and estimating 50% of the landmarks (reproducing the preservation state of Tycho Brahe's cranial remains). The comparison between the FA based on the complete and incomplete skulls of the same subject produced a visual assessment of the estimation impact on FAs which is relatively low. This procedure is an alternative to manual methods and offers a reproducible estimate of a face based on incomplete cranial remains. Although the case report concerns a historical individual, the robust automatic estimation of missing landmarks followed by a FA has value for forensic caseworks as a support to the identification process.
- MeSH
- Anatomic Landmarks MeSH
- History, 16th Century MeSH
- History, 17th Century MeSH
- Skull anatomy & histology MeSH
- Humans MeSH
- Face anatomy & histology MeSH
- Image Processing, Computer-Assisted * MeSH
- Software * MeSH
- Forensic Anthropology methods MeSH
- Famous Persons MeSH
- Imaging, Three-Dimensional MeSH
- Check Tag
- History, 16th Century MeSH
- History, 17th Century MeSH
- Humans MeSH
- Publication type
- Journal Article MeSH
- Historical Article MeSH
BACKGROUND: Endoscopic endonasal transsphenoidal approaches are broadly used nowadays for a vast spectrum of pathologies sited in the anterior and middle cranial fossa. The usage of neuronavigation systems (neuronavigation) in these surgeries is crucial for improving orientations deeply inside the skull and increasing patient safety. METHODS: The aim of this study was to assess the use of optical neuronavigation, together with an intraoperative O-arm O2 imaging system, in a group of patients with hypophyseal adenoma that underwent a transnasal transsphenoidal surgery, and correlate the accuracy and its deviation during the navigational process against the use of conventional neuronavigation that uses preoperative MRI and CT scans. The overall group consisted of six patients, between 39 and 78 years old, with a diagnosis of hypophyseal adenoma. Patients were treated with an endoscopic transsphenoidal technique and all of them underwent preoperative MRI and CT scans of the brain. These images were used in the neuronavigation system StealthStation S7® during the surgery, where we defined two bony anatomical landmarks, such as a vomer or the origin of an intrasphenoidal septum, in each operated patient. The tip of the navigational instrument, under endoscopic control, pointed to these landmarks and the distance between the tip and the bony structure was measured on the neuronavigation system. Afterwards, intraoperative 3D x-ray imaging was performed via the mobile system O-arm O2® system with automatic transfer into the navigational system. Under endoscopic guidance, we localized the identical bony anatomical landmarks used in the previous measurement and re-measured the distance between the tip and bony landmark in images acquired by the O-arm. The results of both measurements were statistically compared. RESULTS: The mean error of accuracy during conventional neuronavigation with usage of preoperative CT and MRI scans was 2.65 mm. During the neuronavigation, with utilization of intraoperative 3D O-arm images, the mean error of accuracy 0 mm. These mean errors of accuracy (both measurement methods were compared by nonparametric Wilcoxon test) had a statistically significant difference (p = 0.043). CONCLUSIONS: Based on this preliminary clinical study, we conclude that the O-arm is capable of providing intraoperative x-ray 3D images in sufficient spatial resolution in a clinically feasible acquisition. The mean error of accuracy during intraoperative navigation, based on 3D O-arm scans at the skull base, is significantly lower compared to the usage of navigation using conventional presurgical CT and MRI images. This suggests the suitability of this method for utilization during endoscopic endonasal skull base approaches.
- MeSH
- Adenoma * diagnostic imaging surgery MeSH
- Skull Base * diagnostic imaging surgery MeSH
- Surgery, Computer-Assisted * methods MeSH
- Adult MeSH
- Pituitary Gland * diagnostic imaging surgery MeSH
- Middle Aged MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Pituitary Neoplasms * diagnostic imaging surgery MeSH
- Neuronavigation methods MeSH
- Intraoperative Period MeSH
- Pilot Projects MeSH
- Tomography, X-Ray Computed MeSH
- Prospective Studies MeSH
- Aged MeSH
- Transanal Endoscopic Surgery * methods MeSH
- Imaging, Three-Dimensional MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
PURPOSE OF THE STUDY Repeated measurements of the spine are absolutely necessary in children and adolescents affected by spinal deformities especially during their growing-up periods. To avoid risks of tissue damage from x-ray exposure, several methods for non-invasive measurement of the spinal curvature have been developed. One of them is the DTP-3 position system allowing for a three-dimensional measurement of anatomical landmarks (spinous processes) and the calculation of curvature angles in both the frontal and sagittal planes. We were interested to know whether the DTP-3 was precise enough to determine the true spinal curvature. MATERIAL AND METHODS To determine the precision of the DTP-3 system, we constructed a model of the spine. The model was then repeatedly investigated by both the noninvasive and x-ray methods. The distortion of x-ray images caused by the central projection mechanism was considered and included in the calculation. In addition, a group of patients with scoliosis up to 40° was evaluated by both the DTP-3 system and x-ray (the latter according to Cobb's method). RESULTS Differences in spatial coordinates between DTP-3 and x-ray examinations reached 20.9 mm in the frontal plane and 67.3 mm in the sagittal plane without distortion correction of x-ray images. The differences decreased below 1.5 mm after image distortion correction in each plane. Distortion correction had not the same effect for angle parameters as for coordinates. Differences between the DTP-3 angle parameters and Cobb's x-ray angles were below 4.7°, both without correction and after correction. The difference between DTP-3 angle parameters and Cobb's x-ray angles was -1.8° ? 3.0° (mean ? standard deviation) when measurement was performed on the patients with scoliosis. DISCUSSION The goal of any clinical examination is to obtain data applicable to decision-making analysis. In the case of scoliosis it is necessary to report results in terms of Cobb's angle, which is the problem for all surface-dependent methods, especially in patients with double curves. A solution may be to define the maximal difference between noninvasive and x-ray methods that could be acceptable for good clinical practice. CONCLUSIONS In this study we report good concordance between noninvasive and x-ray examinations of a modeled spinal deformity in terms of both angle and linear measurements. The same results were obtained for angle measurements in a group of patients with scoliosis up to 40°. Based on this study and our previous data we believe that the DTP-3 system can be introduced into clinical practice.
- MeSH
- Models, Anatomic MeSH
- Humans MeSH
- Adolescent MeSH
- Spine pathology radiography MeSH
- Image Processing, Computer-Assisted MeSH
- Scoliosis diagnosis radiography MeSH
- Software MeSH
- Imaging, Three-Dimensional MeSH
- Check Tag
- Humans MeSH
- Adolescent MeSH
- Male MeSH
- Female MeSH
- Publication type
- Comparative Study MeSH
- Validation Study MeSH
BACKGROUND: Variations observed in biomechanical studies might be attributed to errors made by operators during the construction of musculoskeletal models, rather than being solely attributed to patient-specific geometry. RESEARCH QUESTION: What is the impact of operator errors on the construction of musculoskeletal models, and how does it affect the estimation of muscle moment arms and hip joint reaction forces? METHODS: Thirteen independent operators participated in defining the muscle model, while a single operator performed 13 repetitions to define the muscle model based on 3D bone geometry. For each model, the muscle moment arms relative to the hip joint center of rotation was evaluated. Additionally, the hip joint reaction force during one-legged stance was assessed using static inverse optimization. RESULTS: The results indicated high levels of consistency, as evidenced by the intra- rater and inter-rater agreement measured by the Intraclass Correlation Coefficient (ICC), which yielded values of 0.95 and 0.99, respectively. However, the estimated muscle moment arms exhibited an error of up to 16 mm compared to the reference musculoskeletal model. It was found that muscles attached to prominent anatomical landmarks were specified with greater accuracy than those attached over larger areas. Furthermore, the variability in estimated moment arms contributed to variations of up to 12% in the hip joint reaction forces. SIGNIFICANCE: Both moment arm and muscle force demonstrated significantly lower variability when assessed by a single operator, suggesting the preference for employing a single operator in the creation of musculoskeletal models for clinical biomechanical studies.
- MeSH
- Models, Biological MeSH
- Biomechanical Phenomena MeSH
- Muscle, Skeletal * physiology MeSH
- Hip Joint * physiology MeSH
- Humans MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Developmental instability is a component of non-genetic variation that results from random variation in developmental processes. It is considered a sensitive indicator of the physiological state of individuals. It is reflected in various ways, but in this study we focussed on its reflection in fluctuating asymmetry (FA) and morphological integration. AIM: To assess how, if at all, variations of facial morphology mirror developmental instability across childhood with respect to sex, growth rate and socioeconomic/environmental factors. SUBJECTS AND METHODS: A set of 210 three-dimensional facial models (of children aged between 6.3 and 14.3 years) originating from the FIDENTIS 3D Face Database was subjected to landmark-based methods of geometric morphometrics to quantify the degree of facial asymmetry and facial morphological integration. In addition, the association with age, sex, and socioeconomic factors was assessed. RESULTS: Our results showed a nonlinear increase of FA with age up to the age of 14 years. The pattern of sex-related variants in facial FA differed in relation to age, as girls exhibited higher values of FA than boys up to the age of 9 years. We found that a signal of modularity based on functional demands and organisation of the face is of particular importance. Here, girls exhibited higher morphological covariation among modules. During more rapid adolescence-related growth, however, covariation among modules at the asymmetrical level decreased in both sexes. CONCLUSION: We can conclude that facial morphology was shown to be strongly integrated, particularly until adolescence. This covariation can facilitate an increase of FA. In addition, the results of this study indicate there is a weak association between socioeconomic stress and facial asymmetries. In contrast, sex and growth rate are reflected in developmental instability.
