Image processing for craniofacial landmark identification and measurement: a review of photogrammetry and cephalometry

Evaluating smartphone-based 3D imaging techniques for clinical application in oral and maxillofacial surgery: A comparative study with the vectra M5

PURPOSE

This study aimed to clarify the applicability of smartphone-based three-dimensional (3D) surface imaging for clinical use in oral and maxillofacial surgery, comparing two smartphone-based approaches to the gold standard.

METHODS

Facial surface models (SMs) were generated for 30 volunteers (15 men, 15 women) using the Vectra M5 (Canfield Scientific, USA), the TrueDepth camera of the iPhone 14 Pro (Apple Inc., USA), and the iPhone 14 Pro with photogrammetry. Smartphone-based SMs were superimposed onto Vectra-based SMs. Linear measurements and volumetric evaluations were performed to evaluate surface-to-surface deviation. To assess inter-observer reliability, all measurements were performed independently by a second observer. Statistical analyses included Bland-Altman analyses, the Wilcoxon signed-rank test for paired samples, and Intraclass correlation coefficients.

RESULTS

Photogrammetry-based SMs exhibited an overall landmark-to-landmark deviation of M = 0.8 mm (SD =  ± 0.58 mm, n = 450), while TrueDepth-based SMs displayed a deviation of M = 1.1 mm (SD =  ± 0.72 mm, n = 450). The mean volumetric difference for photogrammetry-based SMs was M = 1.8 cc (SD =  ± 2.12 cc, n = 90), and M = 3.1 cc (SD =  ± 2.64 cc, n = 90) for TrueDepth-based SMs. When comparing the two approaches, most landmark-to-landmark measurements demonstrated 95% Bland-Altman limits of agreement (LoA) of ≤ 2 mm. Volumetric measurements revealed LoA > 2 cc. Photogrammetry-based measurements demonstrated higher inter-observer reliability for overall landmark-to-landmark deviation.

CONCLUSION

Both approaches for smartphone-based 3D surface imaging exhibit potential in capturing the face. Photogrammetry-based SMs demonstrated superior alignment and volumetric accuracy with Vectra-based SMs than TrueDepth-based SMs.

Automatic soft-tissue analysis on orthodontic frontal and lateral facial photographs based on deep learning

BACKGROUND

To establish the automatic soft-tissue analysis model based on deep learning that performs landmark detection and measurement calculations on orthodontic facial photographs to achieve a more comprehensive quantitative evaluation of soft tissues.

METHODS

A total of 578 frontal photographs and 450 lateral photographs of orthodontic patients were collected to construct datasets. All images were manually annotated by two orthodontists with 43 frontal-image landmarks and 17 lateral-image landmarks. Automatic landmark detection models were established, which consisted of a high-resolution network, a feature fusion module based on depthwise separable convolution, and a prediction model based on pixel shuffle. Ten measurements for frontal images and eight measurements for lateral images were defined. Test sets were used to evaluate the model performance, respectively. The mean radial error of landmarks and measurement error were calculated and statistically analysed to evaluate their reliability.

RESULTS

The mean radial error was 14.44 ± 17.20 pixels for the landmarks in the frontal images and 13.48 ± 17.12 pixels for the landmarks in the lateral images. There was no statistically significant difference between the model prediction and manual annotation measurements except for the mid facial-lower facial height index. A total of 14 measurements had a high consistency.

CONCLUSION

Based on deep learning, we established automatic soft-tissue analysis models for orthodontic facial photographs that can automatically detect 43 frontal-image landmarks and 17 lateral-image landmarks while performing comprehensive soft-tissue measurements. The models can assist orthodontists in efficient and accurate quantitative soft-tissue evaluation for clinical application.

Anthropometry and Current Aesthetic Concept of the Lower Third of the Face and Lips in Caucasian Adult Population: A Systematic Review and Meta-Analysis

BACKGROUND

The lack of standardization of the norms and aesthetic concept of the lower third of the face and lips creates challenges in reconstructive surgery and aesthetic procedures. A large-scale, anthropometric measurements summary poses an alternative for establishing universal patterns.

METHODS

A systematic review was conducted by searching PubMed, Embase, Google Scholar and Web of Science using keywords: lip, face, aesthetics, beauty, anthropometry and Caucasian. Seventy records were included in the review and checked in detail in terms of available data.

RESULTS

The study contains a meta-analysis of twelve parameters with sufficient quantitative data-lip width, nose width, facial width, lower third of the face height, midline mandible height, total height of the upper and lower lip, upper and lower vermilion height, cutaneous upper lip height and nasolabial and mentolabial angle.

CONCLUSIONS

The review provides a detailed database of primary anthropometric studies of lips and perioral regions of the healthy Caucasian population. The attractiveness of the region is focused on uniformity of proportions. Notably, results acquired with different methods of measurement are not interchangeable. Despite many published anthropometric studies, systems for conducting the measurements and reporting the results are not sufficiently unified to quantitatively assess meticulous key aesthetic clinical parameters.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine Ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266 .

Craniofacial identification standards: A review of reliability, reproducibility, and implementation

There are numerous anatomical and anthropometrical standards that can be utilised for craniofacial analysis and identification. These standards originate from a wide variety of sources, such as orthodontic, maxillofacial, surgical, anatomical, anthropological and forensic literature, and numerous media have been employed to collect data from living and deceased subjects. With the development of clinical imaging and the enhanced technology associated with this field, multiple methods of data collection have become accessible, including Computed Tomography, Cone-Beam Computed Tomography, Magnetic Resonance Imaging, Radiographs, Three-dimensional Scanning, Photogrammetry and Ultrasound, alongside the more traditional in vivo methods, such as palpation and direct measurement, and cadaveric human dissection. Practitioners often struggle to identify the most appropriate standards and research results are frequently inconsistent adding to the confusion. This paper aims to clarify how practitioners can choose optimal standards, which standards are the most reliable and when to apply these standards for craniofacial identification. This paper describes the advantages and disadvantages of each mode of data collection and collates published research to review standards across different populations for each facial feature. This paper does not aim to be a practical instruction paper; since this field encompasses a wide range of 2D and 3D approaches (e.g., clay sculpture, sketch, automated, computer-modelling), the implementation of these standards is left to the individual practitioner.

"Utility of Smartphone-based Three-dimensional Surface Imaging for Digital Facial Anthropometry"

Background

The utilization of three-dimensional (3D) surface imaging for facial anthropometry is a significant asset for patients undergoing maxillofacial surgery. Notably, there have been recent advancements in smartphone technology that enable 3D surface imaging.In this study, anthropometric assessments of the face were performed using a smartphone and a sophisticated 3D surface imaging system.

Methods

30 healthy volunteers (15 females and 15 males) were included in the study. An iPhone 14 Pro (Apple Inc., USA) using the application 3D Scanner App (Laan Consulting Corp., USA) and the Vectra M5 (Canfield Scientific, USA) were employed to create 3D surface models. For each participant, 19 anthropometric measurements were conducted on the 3D surface models. Subsequently, the anthropometric measurements generated by the two approaches were compared. The statistical techniques employed included the paired t-test, paired Wilcoxon signed-rank test, Bland-Altman analysis, and calculation of the intraclass correlation coefficient (ICC).

Results

All measurements showed excellent agreement between smartphone-based and Vectra M5-based measurements (ICC between 0.85 and 0.97). Statistical analysis revealed no statistically significant differences in the central tendencies for 17 of the 19 linear measurements. Despite the excellent agreement found, Bland-Altman analysis revealed that the 95% limits of agreement between the two methods exceeded ±3 mm for the majority of measurements.

Conclusion

Digital facial anthropometry using smartphones can serve as a valuable supplementary tool for surgeons, enhancing their communication with patients. However, the proposed data suggest that digital facial anthropometry using smartphones may not yet be suitable for certain diagnostic purposes that require high accuracy.

Is automatic cephalometric software using artificial intelligence better than orthodontist experts in landmark identification?

BACKGROUND

To evaluate the techniques used for the automatic digitization of cephalograms using artificial intelligence algorithms, highlighting the strengths and weaknesses of each one and reviewing the percentage of success in localizing each cephalometric point.

METHODS

Lateral cephalograms were digitized and traced by three calibrated senior orthodontic residents with or without artificial intelligence (AI) assistance. The same radiographs of 43 patients were uploaded to AI-based machine learning programs MyOrthoX, Angelalign, and Digident. Image J was used to extract x- and y-coordinates for 32 cephalometric points: 11 soft tissue landmarks and 21 hard tissue landmarks. The mean radical errors (MRE) were assessed radical to the threshold of 1.0 mm,1.5 mm, and 2 mm to compare the successful detection rate (SDR). One-way ANOVA analysis at a significance level of P < .05 was used to compare MRE and SDR. The SPSS (IBM-vs. 27.0) and PRISM (GraphPad-vs.8.0.2) software were used for the data analysis.

RESULTS

Experimental results showed that three methods were able to achieve detection rates greater than 85% using the 2 mm precision threshold, which is the acceptable range in clinical practice. The Angelalign group even achieved a detection rate greater than 78.08% using the 1.0 mm threshold. A marked difference in time was found between the AI-assisted group and the manual group due to heterogeneity in the performance of techniques to detect the same landmark.

CONCLUSIONS

AI assistance may increase efficiency without compromising accuracy with cephalometric tracings in routine clinical practice and research settings.

3-Dimensional Morphometric Outcomes After Endoscopic Strip Craniectomy for Unicoronal Synostosis

BACKGROUND

Endoscopic strip craniectomy with postoperative helmeting (ESCH) for unicoronal synostosis has shown to be a less morbid procedure when compared with fronto-orbital remodeling (FOR). We aim in this pilot study to report objective methods and quantitative morphologic outcomes of endoscopically treated unicoronal synostosis using 3-dimensional surface scans.

METHODS

Our electronic records were reviewed for ophthalmological, neurodevelopmental outcomes, and helmet-related complications. For morphologic outcomes, the following parameters were used: Cranial Index, Cranial Vault Asymmetry Index, Anterior Symmetry Ratio (ASR), and Root Mean Square between the normal and synostotic sides of the head. Three-dimensional stereophotogrammetry scans were evaluated at 3 time points preoperative, 6 months post-op, and at the end of the treatment, which was compared with age-matched scans of normal controls and FOR patients. Nonparametric tests were used for statistical analysis.

RESULTS

None of the ESCH cases developed strabismus, major neurodevelopmental delay, or helmet complications. All morphologic parameters improved significantly at 6 months post-op except for the Cranial Vault Asymmetry Index. The ASR was the only parameter to change significantly between 6 months post-op and final scans. At end of helmet treatment, ASR and Root Mean Square differed significantly between the ESCH and both FOR and control groups.

CONCLUSIONS

Endoscopic strip craniectomy with postoperative helmeting for single unicoronal synostosis had excellent clinical outcomes. Most of the improvement in head morphology occurred in the first 6 months of treatment. Despite the normalization of the overall head shape, there was residual asymmetry in the frontal and temporal regions of the head.

Automation of Measurements for Personalized Medical Appliances by Means of CAD Software-Application in Robin Sequence Orthodontic Appliances

Measuring the dimensions of personalized devices can provide relevant information for the production of future such devices used in various medical specialties. Difficulties with standardizing such measurement and obtaining high accuracy, alongside cost-intensive measuring methodologies, has dampened interest in this practice. This study presents a methodology for automatized measurements of personalized medical appliances of variable shape, in this case an orthodontic appliance known as Tübingen Palatal Plate (TPP). Parameters such as length, width and angle could help to standardize and improve its future use. A semi-automatic and custom-made program, based on Rhinoceros 7 and Grasshopper, was developed to measure the device (via an extraoral scanner digital file). The program has a user interface that allows the import of the desired part, where the user is able to select the necessary landmarks. From there, the program is able to process the digital file, calculate the necessary dimensions automatically and directly export all measurements into a document for further processing. In this way, a solution for reducing the time for measuring multiple dimensions and parts while reducing human error can be achieved.

Accuracy of three-dimensional optical devices for facial soft-tissue measurement in clinical practice of stomatology: A PRISMA systematic review

BACKGROUND

The accuracy of 3-dimensional (3D) optical devices for facial soft-tissue measurement is essential to the success of clinical treatment in stomatology. The aim of the present systematic review was to summarize the accuracy of 3D optical devices used for facial soft-tissue assessment in stomatology.

METHODS

An extensive systematic literature search was performed in the PubMed/MEDLINE, Embase, Scopus and Cochrane Library databases for studies published in the English language up to May 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Peer-reviewed journal articles evaluating the facial soft-tissue morphology by 3D optical devices were included. The risk of bias was performed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2 guidelines by the 2 reviewers. The potential publication bias was analyzed using the Review Manager software.

RESULTS

The query returned 1853 results. A total of 38 studies were included in this review. Articles were categorized based on the principle of devices: laser-based scanning, structured-light scanning, stereophotogrammetry and red, green, blue-depth camera.

CONCLUSION

Overall, the 3D optical devices demonstrated excellent accuracy and reliability for facial soft-tissue measurement in stomatology. red, green, blue-depth camera can collect accurate static and dynamic 3D facial scans with low cost and high measurement accuracy. Practical needs and availability of resources should be considered when these devices are used in clinical settings.

Facial Scanning Accuracy with Stereophotogrammetry and Smartphone Technology in Children: A Systematic Review

The aim of the study was to systematically review and compare the accuracy of smartphone scanners versus stereophotogrammetry technology for facial digitization in children. A systematic literature search strategy of articles published from 1 January 2010 to 30 August 2022 was adopted through a combination of Mesh terms and free text words pooled through boolean operators on the following databases: PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and OpenGrey. Twenty-three articles met the inclusion criteria. Stationary stereophotogrammetry devices showed a mean accuracy that ranged from 0.087 to 0.860 mm, portable stereophotogrammetry scanners from 0.150 to 0.849 mm, and smartphones from 0.460 to 1.400 mm. Regarding the risk of bias assessment, fourteen papers showed an overall low risk, three articles had unclear risk and four articles had high risk. Although smartphones showed less performance on deep and irregular surfaces, all the analyzed devices were sufficiently accurate for clinical application. Internal depth-sensing cameras or external infrared structured-light depth-sensing cameras plugged into smartphones/tablets increased the accuracy. These devices are portable and inexpensive but require greater operator experience and patient compliance for the incremented time of acquisition. Stationary stereophotogrammetry is the gold standard for greater accuracy and shorter acquisition time, avoiding motion artifacts.

An overview of three-dimensional imaging devices in dentistry

OBJECTIVE

To review four types of three-dimensional imaging devices: intraoral scanners, extraoral scanners, cone-beam computed tomography (CBCT), and facial scanners, in terms of their development, technologies, advantages, disadvantages, accuracy, influencing factors, and applications in dentistry.

METHODS

PubMed (National Library of Medicine) and Google Scholar databases were searched. Additionally, the scanner manufacturers' websites were accessed to obtain relevant data. Four authors independently selected the articles, books, and websites. To exclude duplicates and scrutinize the data, they were uploaded to Mendeley Data. In total, 135 articles, two books, and 17 websites were included.

RESULTS

Research and clinical practice have shown that oral and facial scanners and CBCT can be used widely in various areas of dentistry with high accuracy.

CONCLUSION

Although further advancement of these devices is desirable, there is no doubt that digital technology represents the future of dentistry. Furthermore, the combined use of different devices may bring dentistry into a new era. These four devices will play a significant role in clinical utility with high accuracy. The combined use of these devices should be explored further.

CLINICAL SIGNIFICANCE

The four devices will play a significant role in clinical use with high accuracy. The combined use of these devices should be explored further.

Correction of trigonocephaly after endoscopic strip craniectomy with postoperative helmet orthosis therapy: a 3D stereophotogrammetric study

OBJECTIVE

Endoscopic strip craniectomy with postoperative helmet orthosis therapy (ESCH) has emerged as a less invasive alternative to fronto-orbital remodeling for correction of trigonocephaly. However, there is no standardized objective method for monitoring morphological changes following ESCH. Such a method should be reproducible and avoid the use of ionizing radiation and general anesthesia for diagnostic imaging. The authors analyzed a number of metrics measured using 3D stereophotogrammetry (3DSPG) following ESCH, an imaging alternative that is free of ionizing radiation and can be performed on awake children.

METHODS

3DSPG images obtained at two time points (perisurgical and 1-year follow-up [FU]) of children with metopic synostosis who had undergone ESCH were analyzed and compared to 3DSPG images of age-matched control children without craniofacial anomalies. In total, 9 parameters were measured, the frontal angle and anteroposterior volume in addition to 7 novel parameters: anteroposterior area ratio, anteroposterior width ratios 1 and 2, and right and left anteroposterior diagonal ratios 30 and 60.

RESULTS

Six eligible patients were identified in the operated group, and 15 children were in the control group. All 9 parameters differed significantly between perisurgical and age-matched controls, as well as from perisurgical to FU scans. Comparison of FU scans of metopic synostosis patients who underwent surgery to scans of age-matched controls without metopic synostosis revealed that all parameters were statistically identical, with the exception of the right anteroposterior diagonal ratio 30, which was not fully corrected in the treated patients. The left anterior part of the head showed the most change in surface area maps.

CONCLUSIONS

In this pilot study, ESCH showed satisfactory results at 1 year, with improvements in all measured parameters compared to perisurgical results and normalization of 8 of 9 parameters compared to an age-matched control group. The results indicate that these parameters may be useful for craniofacial units for monitoring changes in head shape after ESCH for trigonocephaly and that 3DSPG, which avoids the use of anesthesia and ionizing radiation, is a satisfactory monitoring method.

Cephalometric Landmark Detection in Lateral Skull X-ray Images by Using Improved SpatialConfiguration-Net

Accurate automated localization of cephalometric landmarks in skull X-ray images is the basis for planning orthodontic treatments, predicting skull growth, or diagnosing face discrepancies. Such diagnoses require as many landmarks as possible to be detected on cephalograms. Today’s best methods are adapted to detect just 19 landmarks accurately in images varying not too much. This paper describes the development of the SCN-EXT convolutional neural network (CNN), which is designed to localize 72 landmarks in strongly varying images. The proposed method is based on the SpatialConfiguration-Net network, which is upgraded by adding replications of the simpler local appearance and spatial configuration components. The CNN capacity can be increased without increasing the number of free parameters simultaneously by such modification of an architecture. The successfulness of our approach was confirmed experimentally on two datasets. The SCN-EXT method was, with respect to its effectiveness, around 4% behind the state-of-the-art on the small ISBI database with 250 testing images and 19 cephalometric landmarks. On the other hand, our method surpassed the state-of-the-art on the demanding AUDAX database with 4695 highly variable testing images and 72 landmarks statistically significantly by around 3%. Increasing the CNN capacity as proposed is especially important for a small learning set and limited computer resources. Our algorithm is already utilized in orthodontic clinical practice.

Long-Term Morphologic Changes on Sagittal Synostosis Patients Who Underwent a Modified Pi Technique

BACKGROUND

There are paucity of studies focused on the long-term assessment of the craniofacial changes after a pi-plasty procedure and self-reported quality of life outcomes. Thus, this study aimed to assess long-term morphologic changes and quality of life of patients with sagittal synostosis who underwent surgery with a modified pi-plasty.

METHODS

Consecutive patients with sagittal synostosis who underwent surgery and had more than 5 years of follow-up and standard preoperative and 1, 3, and 5 years right profile view photographs were included. Nasofrontal angle and angle of total facial convexity were evaluated using computerized photogrammetric measurements. Additionally, quality of life outcome was evaluated by the Quality of Life Scale Short Form.

RESULTS

The total facial convexity angle and nasofrontal angle increased significantly (P < 0.05), with a P-value of 0.013 and 0.012, respectively. Patients had quality of life scores >80 in all of the 4 domains, with the highest scores being: physical health domain 80.0 ± 0, psychologic domain 85.0 ± 5, social relationships domain 86.6 ± 0, and environmental domain 98.13 ± 2.42.

CONCLUSION

Facial angles significantly changed over 5 years of follow-up. Self-reported quality of life instrument showed that patients are satisfied with their own appearance, contributing positively to their quality of life.

Accuracy of Portable Face-Scanning Devices for Obtaining Three-Dimensional Face Models: A Systematic Review and Meta-Analysis

The use of three-dimensional face-scanning systems to obtain facial models is of increasing interest, however, systematic assessments of the reliability of portable face-scan devices have not been widely conducted. Therefore, a systematic review and meta-analysis were performed considering the accuracy of facial models obtained by portable face-scanners in comparison with that of those obtained by stationary face-scanning systems. A systematic literature search was conducted in electronic databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for articles published from 1 January 2009 to 18 March 2020. A total of 2806 articles were identified, with 21 articles available for the narrative review and nine studies available for meta-analysis. The meta-analysis revealed that the accuracy of the digital face models generated by the portable scanners was not significantly different from that of the stationary face-scanning systems (standard mean difference (95% confidence interval) = -0.325 mm (-1.186 to 0.536); z = -0.74; p = 0.459). Within the comparison of the portable systems, no statistically significant difference was found concerning the accuracy of the facial models among scanning methods (p = 0.063). Overall, portable face-scan devices can be considered reliable for obtaining facial models. However, caution is needed when applying face-scanners with respect to scanning device settings, control of involuntary facial movements, landmark and facial region identifications, and scanning protocols.

Accuracy of Mobile Device-Compatible 3D Scanners for Facial Digitization: Systematic Review and Meta-Analysis

Background

The accurate assessment and acquisition of facial anatomical information significantly contributes to enhancing the reliability of treatments in dental and medical fields, and has applications in fields such as craniomaxillofacial surgery, orthodontics, prosthodontics, orthopedics, and forensic medicine. Mobile device–compatible 3D facial scanners have been reported to be an effective tool for clinical use, but the accuracy of digital facial impressions obtained with the scanners has not been explored.

Objective

We aimed to review comparisons of the accuracy of mobile device–compatible face scanners for facial digitization with that of systems for professional 3D facial scanning.

Methods

Individual search strategies were employed in PubMed (MEDLINE), Scopus, Science Direct, and Cochrane Library databases to search for articles published up to May 27, 2020. Peer-reviewed journal articles evaluating the accuracy of 3D facial models generated by mobile device–compatible face scanners were included. Cohen d effect size estimates and confidence intervals of standardized mean difference (SMD) data sets were used for meta-analysis.

Results

By automatic database searching, 3942 articles were identified, of which 11 articles were considered eligible for narrative review, with 6 studies included in the meta-analysis. Overall, the accuracy of face models obtained using mobile device–compatible face scanners was significantly lower than that of face models obtained using professional 3D facial scanners (SMD 3.96 mm, 95% CI 2.81-5.10 mm; z=6.78; P<.001). The difference between face scanning when performed on inanimate facial models was significantly higher (SMD 10.53 mm, 95% CI 6.29-14.77 mm) than that when performed on living participants (SMD 2.58 mm, 95% CI 1.70-3.47 mm, P<.001, df=12.94).

Conclusions

Overall, mobile device–compatible face scanners did not perform as well as professional scanning systems in 3D facial acquisition, but the deviations were within the clinically acceptable range of <1.5 mm. Significant differences between results when 3D facial scans were performed on inanimate facial objects and when performed on the faces of living participants were found; thus, caution should be exercised when interpreting results from studies conducted on inanimate objects.

Application of tpsDig2 Software in Nasal Angle Measurements

INTRODUCTION AND OBJECTIVES

Nose is considered to be a conspicuous feature of human face. Its different parameters like shape, size, nasal angles etc may indicate one's gender, age, race, adapted climatic conditions, and the environment to which one belongs to. Furthermore, it is an important component and determinant of an individual's physical outlook and appearance. The current study provides a new approach for the assistance of anthropologists and forensic experts in human identification and sex determination from the nasal angles.

METHODOLOGY

The study was performed on a total of 500 subjects (250 males and 250 females) belonging to north India (Mandi, Himachal Pradesh State). In comparison to the classical and manual methods for nasal angle measurements, an automated approach was followed in the present study. A Windows-based software called tpsDig2 was used for nasal angle measurements by utilization of the landmarks (nasion, pronasale, subnasale, and alare). Three nasal angles (nasal prominence angle, inter-alar angle, and nasal tip angle) were measured in all the subjects and each measurement was repeated thrice to reduce the measurement error and increase the specificity and efficiency of the results. Discriminant function statistics was used for determination of sex from different nasal angles.

RESULTS AND CONCLUSION

The results of the statistical analysis (ANOVA) performed using SPSS reveal the significant difference between males and females in all the 3 repeated measurements of nasal angles. The final discriminant classification statistics show that 64% of original grouped cases have been correctly classified and the designed statistical model can be used in several forensic scenarios for the sex determination on the basis of the available nasal angles. The study may be further useful in the identification cases pertaining to facial reconstruction. The investigation may also be helpful in providing specific correlation of the nasal angles with the other parts of the face in the cases of remodelling and reformation of craniofacial alterations and reconstructions in plastic surgery and aesthetics.

Scan time, reliability and accuracy of craniofacial measurements using a 3D light scanner

Aim

To evaluate time, reliability and accuracy of craniofacial measurements with a 3D light scanner, considering prior demarcation of surface points on the face.

Materials and methods

Eleven facial measurements of 15 volunteers were obtained by a scanner (Artec Eva TM) and by a caliper directly on the face, with or without demarcation of facial reference points. Inter and intra-method comparison were examined by intraclass correlation coefficient and analysis of random error by the Dahlberg formula. Agreement between the methods was analyzed by the Bland-Altman. A Wilcoxon test was used to compare the time for each method, at p < 0.05.

Results

Marking points on the face improved accuracy for both methods. In the inter-methods analysis with landmarks, the scanner showed excellent reliability in all measures (ICC = 0.92-0.97, p < 0.0001). Measurements accuracy with scanner was around 2 mm when the points were not previously marked and about 1 mm when the points were marked. Measures taken with the scanner, however, took twice as long, compared with the direct method.

Conclusions

Craniofacial measurements obtained with scanner showed excellent reliability and accuracy, which qualifies this method for clinical and scientific use. Accuracy is improved when the points were previously marked on face. However, the time needed to obtain measurements is greater than about 4 min for the direct method.

Caucasian Mediterranean patients seeking rhinoplasty-Anthropometric measurements and prevalence of major deformities

OBJECTIVE

To describe the average values of the nasal anthropometric measurements of Caucasian Mediterranean patients seeking rhinoplasty and evaluate the major nasal deformities.

DESIGN

Prospective, observational and cross-sectional study.

SETTING

Centro Hospitalar do Porto.

PARTICIPANTS

A 100 Caucasian Mediterranean patients seeking rhinoplasty.

OUTCOMES

Standardized photography was used to obtain nasal anthropometric measurements and to evaluate the major nasal defects. Data regarding age, gender, skin type and Fitzpatrick scale were also collected.

RESULTS

There was a statistically significant difference in the means values of palpebral fissure, intercanthal width, upper lip height, nasal root width, morphological nose width, nose height, nasal tip projection and nasofrontal-hump and nasofrontal-supratip angles between females and males. The major nasal deformity was dorsal hump (78.0%), followed by rinomegalia (53.0%) and boxy bulbous tip (47.0%).

CONCLUSION

The present study shows statistically significant gender differences between anthropometric nasal measurements and the mean values are greater than standard values obtained on general population. This might be one of the reasons why Caucasian Mediterranean patients seek aesthetical rhinoplasty. On both genders, dorsal hump, rinomegalia and boxy bulbous tip were the major nasal defects. This emphasize the importance of rhinoplasty techniques designed to reconstruct nasal dorsum and nasal tip on Caucasian Mediterranean patients. To the best of our knowledge, our study is the first study of digital anthropometric nasal analysis and evaluation of major nasal defects specifically in Caucasian Mediterranean patients who applied for rhinoplasty. With this results, we provide a reference material for the evaluation of the Caucasian and Mediterranean patient when planning a cosmetic nasal surgery.

Perspective: Are We Ready to Measure Child Nutritional Status with Lasers?

The continued use of basic, manual anthropometric tools (e.g., boards and tapes) leaves anthropometry susceptible to human error. A potential solution, 3-dimensional (3D) imaging systems for anthropometry, has been around since the 1950s. In the 1980s, 3D imaging technology advanced from photographs to the use of lasers for body digitization; and by the 2000s, the falling price of 3D scanners made commercial application feasible. The garment sector quickly adopted imaging technology for surveys because of the need for numerous measurements and large sample sizes. In the health sector, 3D imaging for anthropometry was not widely adopted; its use was limited to research and specialized purposes. The different cost and logistical requirements for measurement in the garment and health sectors help to explain why the technology was adopted in one sector and not the other. Despite reductions, the price of 3D imaging systems remained a barrier to the use of 3D imaging for regular nutritional assessment in the health sector. Additional barriers in the health sector were that imaging systems required dedicated space and were not designed for capturing measurements in young children. In recent years, the development of light-coding technology may have removed these barriers, and a handheld imaging system was developed specifically for young children. There are not yet recommendations to replace manual equipment with 3D imaging for nutritional assessment, and there is a need for more research on low-cost, handheld imaging systems-particularly research that evaluates the ability of 3D imaging to improve the quality of anthropometric data and indicators.

Automatic Analysis of Lateral Cephalograms Based on Multiresolution Decision Tree Regression Voting

Cephalometric analysis is a standard tool for assessment and prediction of craniofacial growth, orthodontic diagnosis, and oral-maxillofacial treatment planning. The aim of this study is to develop a fully automatic system of cephalometric analysis, including cephalometric landmark detection and cephalometric measurement in lateral cephalograms for malformation classification and assessment of dental growth and soft tissue profile. First, a novel method of multiscale decision tree regression voting using SIFT-based patch features is proposed for automatic landmark detection in lateral cephalometric radiographs. Then, some clinical measurements are calculated by using the detected landmark positions. Finally, two databases are tested in this study: one is the benchmark database of 300 lateral cephalograms from 2015 ISBI Challenge, and the other is our own database of 165 lateral cephalograms. Experimental results show that the performance of our proposed method is satisfactory for landmark detection and measurement analysis in lateral cephalograms.

Anthropometric Analysis of the External Nose of the Egyptian Males

OBJECTIVE

The aim of this study was to describe average nasal anthropometric measurements for young Egyptian males by using the Rhinobase^® software.

MATERIALS AND METHODS

This was a cross-sectional study involving the evaluation of facial photographs. Frontal, right lateral and basal photographs for 300 healthy adult male Egyptian volunteers (n = 300) were taken; then, the photos were edited using Rhinobase^® Software and CorelDraw graphics (2017) software. Twenty anthropometric landmarks were determined. The calculated measurements of the soft tissue of the external nose included ten linear measurements and five angles.

RESULTS

The means of the linear measurements of the external nose in this study were as follows: nasal height (56.12 mm), nasal bridge length (47.0 mm), columella length (9.1 mm), alar length (29.3 mm), morphological nose width (41.0 mm), anatomical nose width (38.0 mm), nasal tip protrusion (21.0 mm), nasal tip projection using 'Goode's method' (29.36 mm), dorsum width (9.6 mm) and nasion height (2.04 mm). The means of the angular measurements of the nose were as follows: nasofacial angle (33.1°), nasofrontal angle (144.0°), nasolabial angle (104.5°), nasomental angle (127.6°) and mentocervical angle (104.7°).

CONCLUSIONS

Racial differences of the external nasal anthropometric values exist; hence, it is important to establish the average anthropometric measures for several races and ethnic groups. Measurements collected in this study can serve as a database for anthropometric average values of the external nose in healthy adult Egyptian males. Moreover, these measurements can aid in planning prior to nasal reconstruction and esthetic rhinoplasty by serving as a reference standard. Although the Rhinobase^® software is an easy, reliable and safe indirect method for nasal analysis, we should be cautious during interpretation of some edited landmarks on Rhinobase^® software pictures. In addition, inserting two rulers (in the horizontal and vertical dimension) allows accurate assessment of the linear anthropometric measurements.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Computer Image-Guided Template for Horizontal Advancement Genioplasty

BACKGROUND

Horizontal advancement genioplasty can be extremely rewarding for microgenia. However, it is challenging for even very experienced surgeon to determine the three-dimensional position of the distant bone fragment during the operation. This study aimed to apply and evaluate computer-aided design (CAD) and computer-aided manufacturing techniques for horizontal advancement genioplasty to improve surgical accuracy.

METHODS

Seven patients with microgenia were prospectively enrolled in the study. Preoperative and postoperative computed tomography (CT), photographs, and lateral cephalograms were performed. Computer-aided design was done based on preoperative CT data, and then surgical templates (cutting guide templates and fixation templates) were designed accordingly to guide horizontal advancement genioplasty. All surgeries were performed by junior surgeons. The accuracy of the authors' method was evaluated by the relative error (the mean value of discrepancy between postoperative CT and preoperative design at 6 points selected randomly/preoperative design movement × 100%), Pg position error (postoperative Pg Advancement - preoperative CAD Pg Advancement)/preoperative CAD Pg Advancement × 100%), and Me position error (postoperative Me downward movement - preoperative CAD Me downward movement)/preoperative CAD Me downward movement × 100%). They are all calculated by Geomagic automatically.

RESULTS

All 7 patients were satisfied with their aesthetic outcomes. The average absolute relative error is 1.8%. The average absolute Pg position error is 1.9% and the average absolute Me position error value is 1.3%.

CONCLUSIONS

The authors' study showed that applying computer-assisted techniques for horizontal advancement genioplasty provided accurate surgical result. With this technique, best result for horizontal advancement genioplasty could be achieved by even inexperienced surgeons.

A Survey on Computer Vision for Assistive Medical Diagnosis From Faces

Automatic medical diagnosis is an emerging center of interest in computer vision as it provides unobtrusive objective information on a patient's condition. The face, as a mirror of health status, can reveal symptomatic indications of specific diseases. Thus, the detection of facial abnormalities or atypical features is at upmost importance when it comes to medical diagnostics. This survey aims to give an overview of the recent developments in medical diagnostics from facial images based on computer vision methods. Various approaches have been considered to assess facial symptoms and to eventually provide further help to the practitioners. However, the developed tools are still seldom used in clinical practice, since their reliability is still a concern due to the lack of clinical validation of the methodologies and their inadequate applicability. Nonetheless, efforts are being made to provide robust solutions suitable for healthcare environments, by dealing with practical issues such as real-time assessment or patients positioning. This survey provides an updated collection of the most relevant and innovative solutions in facial images analysis. The findings show that with the help of computer vision methods, over 30 medical conditions can be preliminarily diagnosed from the automatic detection of some of their symptoms. Furthermore, future perspectives, such as the need for interdisciplinary collaboration and collecting publicly available databases, are highlighted.

Facial anthropometric analysis of a healthy group of young Brazilian adults by means of stereophotogrammetry technique

Abstract Introduction: Anthropometry is the science responsible for measuring the weight, size, and proportions of the human body, providing valuable and objective insights into how to characterize phenotypic variation and dysmorphology. Among the newer methods for facial analysis, the stereophotogrammetry technique has shown excellent results given its use of a group of fast cameras that photograph subjects from multiple angles. Objective: The aims of the present study were: (1) to analyze the facial profile of a group of healthy young Brazilian adults, between 18 and 30 years of age, (2) to define common facial values among the subjects, (3) to create a database of facial measurements of a portion of this young healthy Brazilian population to be used in future works, and (4) to test the precision and repeatability of the Vectra M3® equipment. Material and method: Sixty healthy young Brazilian adults participated in the study, 30 males and 30 females. Temporary craniometrical landmarks were performed in soft tissue, and those subjects underwent image capturing by the stereophotogrammetry technique. Thirty landmarks were used to take the measurements (in mm) of 35 distances. The equipment repeatability was tested in 20% of the sample (i.e., 12 subjects). Result: The values between the first and second acquisitions were statistically (p<0.05) similar for all 35 distances analyzed. The findings allowed the creation of a reliable database containing facial distances of a portion of the young healthy Brazilian population. In addition, the distances Tr-N, N-Sn, Ls-Sto, Sto-Li, En[r]-En[l] and Prn-Sn were not statistically different for the group of men (GM) and the group of women (GW), while the other 29 distances were significantly greater in GM. Conclusion: The technique and methods employed in the study yielded objective analyses of the facial profile of this group of healthy young Brazilian adults, and the equipment Vectra M3® showed a high level of precision and repeatability.

Isolated Autologous Free Fat Grafting for Management of Facial Contour Asymmetry in a Subset of Growing Patients With Craniofacial Microsomia

BACKGROUND

To report autologous free fat grafting as an isolated procedure to manage facial contour asymmetry of a subset of growing patients with craniofacial microsomia (CFM).

METHODS

A retrospective analysis of CFM patients (n = 11) with low socioeconomic and intellectual status, poor oral hygiene, living far from our center, Pruzansky-Kaban I/II mandibles, without functional concerns, and with no craniofacial skeletal surgery who underwent isolated free fat grafting between 2012 and 2013 was conducted. Surgeon and parent/patient satisfaction were elicited. Computerized photogrammetric quantitative and qualitative facial symmetry analyses were performed.

RESULTS

All patients underwent isolated autologous free fat grafting to restore the facial contour symmetry. Surgeon and patient/parent were mostly satisfied. There were significant (all P < 0.05) postoperative quantitative facial symmetry enhancement and an overall qualitative facial symmetry enhancement.

CONCLUSIONS

A significant improvement of facial symmetry was obtained in this subset of growing CFM patients using only isolated free fat grafting.

Progressive frontal morphology changes during the first year of a modified Pi procedure for scaphocephaly

PURPOSE

The purpose of this study was to quantify the changes in frontal morphology in patients with scaphocephaly treated with a modified Pi procedure.

METHODS

Consecutive scaphocephalic patients (n = 13) who underwent surgery before 12 months of age that had more than 1 year of follow-up and standard preoperative, 3-month, and 1-year photographs were included. Anthropometric measurements were used to document the craniofacial index. Computerized photogrammetric analyses of five craniofacial angles (bossing angle, nasofrontal angle, angle of facial convexity, and angle of total facial convexity) were also performed.

RESULTS

Comparisons of the preoperative and postoperative direct anthropometric measurements of the cephalic index showed a significant (all p < 0.05) increase in the postoperative period, with no significant differences in early versus late postoperative period comparisons. Comparisons of the preoperative and postoperative computerized photogrammetric measurements of the craniofacial angles showed a significant (all p < 0.05) reduction (bossing angle, angle of facial convexity, and angle of total facial convexity) and increase (nasofrontal angle) in the early and late postoperative periods.

CONCLUSIONS

Frontal morphology significantly changed over the first year of the modified Pi procedure.

Morphometrics, 3D Imaging, and Craniofacial Development

Recent studies have shown how volumetric imaging and morphometrics can add significantly to our understanding of morphogenesis, the developmental basis for variation, and the etiology of structural birth defects. On the other hand, the complex questions and diverse imaging data in developmental biology present morphometrics with more complex challenges than applications in virtually any other field. Meeting these challenges is necessary in order to understand the mechanistic basis for variation in complex morphologies. This chapter reviews the methods and theory that enable the application of modern landmark-based morphometrics to developmental biology and craniofacial development, in particular. We discuss the theoretical foundations of morphometrics as applied to development and review the basic approaches to the quantification of morphology. Focusing on geometric morphometrics, we discuss the principal statistical methods for quantifying and comparing morphological variation and covariation structure within and among groups. Finally, we discuss the future directions for morphometrics in developmental biology that will be required for approaches that enable quantitative integration across the genotype-phenotype map.

Noninvasive computerized scanning method for the correlation between the facial soft and hard tissues for an integrated three-dimensional anthropometry and cephalometry

OBJECTIVES

The article describes a new methodology to scan and integrate facial soft tissue surface with dental hard tissue models in a three-dimensional (3D) virtual environment, for a novel diagnostic approach.The facial and the dental scans can be acquired using any optical scanning systems: the models are then aligned and integrated to obtain a full virtual navigable representation of the head of the patient.

METHODS

In this article, we report in detail and further implemented a method for integrating 3D digital cast models into a 3D facial image, to visualize the anatomic position of the dentition. This system uses several 3D technologies to scan and digitize, integrating them with traditional dentistry records. The acquisitions were mainly performed using photogrammetric scanners, suitable for clinics or hospitals, able to obtain high mesh resolution and optimal surface texture for the photorealistic rendering of the face. To increase the quality and the resolution of the photogrammetric scanning of the dental elements, the authors propose a new technique to enhance the texture of the dental surface.

RESULTS

Three examples of the application of the proposed procedure are reported in this article, using first laser scanning and photogrammetry and then only photogrammetry. Using cheek retractors, it is possible to scan directly a great number of dental elements. The final results are good navigable 3D models that integrate facial soft tissue and dental hard tissues. The method is characterized by the complete absence of ionizing radiation, portability and simplicity, fast acquisition, easy alignment of the 3D models, and wide angle of view of the scanner.

CONCLUSIONS

This method is completely noninvasive and can be repeated any time the physician needs new clinical records. The 3D virtual model is a precise representation both of the soft and the hard tissue scanned, and it is possible to make any dimensional measure directly in the virtual space, for a full integrated 3D anthropometry and cephalometry. Moreover, the authors propose a method completely based on close-range photogrammetric scanning, able to detect facial and dental surfaces, and reducing the time, the complexity, and the cost of the scanning operations and the numerical elaboration.

Photographic Facial Soft Tissue Analysis by Means of Linear and Angular Measurements in an Adolescent Persian Population

Objective : To obtain objective average measurements of the profile and frontal facial soft tissue to be used as a guide for aesthetic treatment goals. Methods and Materials : This observational study included 110 females and 130 males high school students aged 16-18 years. None of the subjects had any facial deformities. All of them and their parents gave consent to take part in this study. In each case, two standard photographs of profile and frontal views were taken 27 landmarks were digitized on photographs. The mean, standard deviation, and range for a total of 43 facial indices were calculated digitally by computer software. The Student’s t-test was used to compare males and females. Results : The ratio between the lower and middle facial thirds was one to one, but the height of the upper facial third was proportionally smaller than the other two-thirds in both sexes. Boys had greater nasal length, depth, and prominence than girls with statistically significant differences. Both upper and lower lips were more prominent in girls than in boys. All measurements of the chin showed sexual dimorphism characterized by greater chin height and prominence and deeper mentolabial sulcus. Boys had greater facial dimensions than girls. Mouth width, nasal base width, and intercanthal distance were significantly greater in boys. Conclusion : The labial, nasal, and chin areas showed sexual dimorphism in most of the parameters used in this study. Boys had larger faces, greater facial heights, longer nasal, labial, and chin lengths, and greater nasal, labial, and chin prominence.

Facial changes after early treatment of unilateral coronal synostosis question the necessity of primary nasal osteotomy

BACKGROUND

The premature fusion of unilateral coronal suture can cause a significant asymmetry of the craniofacial skeleton, with an oblique deviation of the cranial base that negatively impacts soft tissue facial symmetry. The purpose of this study was to assess facial symmetry obtained in patients with unilateral coronal synostosis (UCS) surgically treated by 2 different techniques. We hypothesized that nasal deviation should not be addressed in a primary surgical correction of UCS.

METHODS

Consecutive UCS patients were enrolled in a prospective study and randomly divided into 2 groups. In group 1, the patients underwent total frontal reconstruction and transferring of onlay bone grafts to the recessive superior orbital rim (n = 7), and in group 2, the patients underwent total frontal reconstruction and unilateral fronto-orbital advancement (n = 5). Computerized photogrammetric analysis measured vertical and horizontal axis of the nose and the orbital globe in the preoperative and postoperative periods. Intragroup and intergroup comparisons were performed.

RESULTS

Intragroup preoperative and postoperative comparisons showed a significant (all P < 0.05) reduction of the nasal axis and the orbital-globe axis in the postoperative period in the 2 groups. Intergroup comparisons showed no significant difference (all P > 0.05).

CONCLUSIONS

Facial symmetry was achieved in the patients with UCS who underwent surgery regardless of surgical approach evaluated here. Our data showed a significant improvement in nasal and orbital-globe deviation, leading us to question the necessity of primary nasal correction in these patients.

3D facial landmarks: Inter-operator variability of manual annotation

Background

Manual annotation of landmarks is a known source of variance, which exist in all fields of medical imaging, influencing the accuracy and interpretation of the results. However, the variability of human facial landmarks is only sparsely addressed in the current literature as opposed to e.g. the research fields of orthodontics and cephalometrics. We present a full facial 3D annotation procedure and a sparse set of manually annotated landmarks, in effort to reduce operator time and minimize the variance.

Method

Facial scans from 36 voluntary unrelated blood donors from the Danish Blood Donor Study was randomly chosen. Six operators twice manually annotated 73 anatomical and pseudo-landmarks, using a three-step scheme producing a dense point correspondence map. We analyzed both the intra- and inter-operator variability, using mixed-model ANOVA. We then compared four sparse sets of landmarks in order to construct a dense correspondence map of the 3D scans with a minimum point variance.

Results

The anatomical landmarks of the eye were associated with the lowest variance, particularly the center of the pupils. Whereas points of the jaw and eyebrows have the highest variation. We see marginal variability in regards to intra-operator and portraits. Using a sparse set of landmarks (n=14), that capture the whole face, the dense point mean variance was reduced from 1.92 to 0.54 mm.

Conclusion

The inter-operator variability was primarily associated with particular landmarks, where more leniently landmarks had the highest variability. The variables embedded in the portray and the reliability of a trained operator did only have marginal influence on the variability. Further, using 14 of the annotated landmarks we were able to reduced the variability and create a dense correspondences mesh to capture all facial features.

Relação entre a desnutrição infantil e a antropometria orofacial

OBJETIVOS: descrever medidas antropométricas orofaciais segundo a idade e o sexo; comparar a média do lado esquerdo da face com a média do lado direito da face, segundo a idade e o sexo. MÉTODOS: 27 crianças afro-descendentes portadoras de desnutrição com idade entre 4 e 6 anos. RESULTADOS: não houve diferença estatística para as medidas antropométricas orofaciais segundo idade e sexo. Para lábio inferior, filtro e o lado esquerdo da face, as medidas apresentaram-se em proporção maior no sexo masculino. Não foi constatada diferença significante entre o lado direito e o lado esquerdo no que se refere à distância do canto externo do olho ao cheilion, segundo idade e sexo. CONCLUSÃO: a idade não representou significância nos achados, mas ocorreram diferenças para o fator sexo. Não há diferenças estatísticas na comparação das medidas entre os lados da face para idade ou sexo.

Digital anthropometric shape analysis of 110 rhinoplasty patients in the Black Sea Region in Turkey

PURPOSE

The aim of the study was to describe the average values of the nasal anthropometric measurements by using the landmark-based geometric morphometric technique in young male patients who applied for rhinoplasty in the Black Sea Region in Turkey.

MATERIALS AND METHODS

The study group consisted of 110 healthy male patients all were born in the Black Sea Region, Turkey. The landmark-based geometric morphometric technique was used to analyze the nasal shapes as described in the literature. The mean age was 29 years (ranging from 23 to 35). All patients underwent primary rhinoplasty in our clinic between 2006 and 2011 years. All data were obtained from standardized digital photographic images. Anterior and worm's eye view photos of the patients were analyzed by using standard anthropometric measurement methods.

RESULTS

The mean total length and nasal bridge length of the noses were 58.90 and 57.35 mm, respectively. The mean nasal bridge width and the morphologic nose width were 32.65 and 35.50mm, respectively. The average width of the anatomic nose was 26.25 mm. The mean length and width of the ala were 22.72 and 4.73 mm, respectively. The mean length and width of the columella were 11.35 and 5.20mm, respectively. The mean frontonasal angle was 137.88° and the mean nasolabial angle was 87.34°.

CONCLUSION

Black Sea nose was characterized by being considerably longer than average in nasal length and columellar height. Also nasolabial angle was found to be more acute than average when compared to other noses.

Accuracy and Repeatability of Anthropometric Facial Measurements Using Cone Beam Computed Tomography

Objective

The purpose of this study was to determine the accuracy and repeatability of linear anthropometric measurements on the soft tissue surface model generated from cone beam computed tomography scans.

Materials and Methods

The study sample consisted of seven cadaver heads. The accuracy and repeatability were assessed by means of a series of 21 standardized, linear facial measurements derived from 11 landmarks taken both directly on the face with a set of digital calipers and indirectly from a three-dimensional soft tissue surface model generated from a cone beam computed tomography scan of the heads using SimPlant® Ortho Pro software. The landmarks and measurements were chosen to cover various regions of the face with an emphasis on the oral-nasal region. The cone beam computed tomography measurements were compared with the physical measurements. Statistical analysis for the repeatability was done by means of the intraclass coefficient. Accuracy was determined by means of the absolute error and absolute percentage error.

Results

The cone beam computed tomography measurements were very accurate when compared with the physical measurements (0.962 to 0.999). Except for one measurement, between point tragion (t) and nasion (n) (mean, 1.52 mm), all the measurements had a mean absolute error of less than 1.5 mm.

Conclusions

The three-dimensional surface models derived from cone beam computed tomography images are sufficiently precise and accurate for the anthropometric measurements.

Three-dimensional photogrammetry for surgical planning of tissue expansion in hemifacial microsomia

BACKGROUND

We aim to illustrate the applications of 3-dimensional (3-D) photogrammetry for surgical planning and longitudinal assessment of the volumetric changes in hemifacial microsomia.

METHODS

A 3-D photogrammetric system was employed for planning soft tissue expansion and transplantation of a vascularized scapular flap for a patient with hemifacial microsomia. The facial deficiency was calculated by superimposing a mirror of the normal side on the preoperative image. Postsurgical volumetric changes were monitored by serial superimposition of 3-D images.

RESULTS

A total of 31 cm(3) of tissue expansion was achieved within a period of 4 weeks. A scapular free flap measuring 8 cm × 5 cm was transplanted to augment the facial deficiency. Postsurgical shrinkage of the flap was observed mainly in the first 3 months and it was minimal thereafter.

CONCLUSION

3-D photogrammetry can be used as a noninvasive objective tool for assessing facial deformity, planning, and postoperative follow-up of surgical correction of facial asymmetry.

Three-Dimensional Color Maps: A Novel Tool for Assessing Craniofacial Changes

Introduction. Three-dimensional (3D) color maps are useful for analyzing data acquired by laser scanning, stereophotography, or computed tomography (CT). The authors aim to illustrate the different applications of color maps in the craniomaxillofacial region. Methods. The images obtained from the above techniques at 2 different time points are superimposed based on a common area unaffected by the surgical intervention or growth. Using specialized software, the distance differences between the 2 superimposed images are depicted in a graphical format as a 3D color map. A color-coded scale indicating the distances accompanies these maps. Results. 3D color maps can be manipulated and viewed in a variety of angles to extract the maximum diagnostic information. They facilitate the critical evaluation of facial asymmetry, accuracy of fusing CT and 3D photo data sets, and postsurgical changes. Conclusion. 3D color maps aid the objective assessment of craniofacial structures while enhancing visual comprehension and communication with patients.

Computer-Aided Maxillofacial Surgery: An Update

Introduction. Recent developments in technology have revolutionized medicine and surgery. This article aims at providing an update on the current trends in computer-aided maxillofacial surgery and illustrates these advances with clinical cases. Methods. The PubMed database was searched for articles published during the past 5 years using the keywords “maxillofacial” and “surgery, computer-assisted.” Full texts of relevant articles were retrieved, and their study details were extracted. Results. Among the 133 articles, most focused on cone-beam computed tomography (CBCT), stereophotography, surgical panning software, and intraoperative navigation. Stereophotography produces 3D facial photographs with natural color and texture, whereas CBCT generates excellent hard-tissue images with a substantially lower radiation than conventional CT scans. Information gathered from CBCT and stereophotography can be used for accurate diagnosis, virtual planning, and simulation of surgery with the aid of specialized software. The preplanned treatment can be executed accurately via intraoperative surgical navigation. Conclusion. Tremendous potential exists for computer-aided maxillofacial surgery as it moves from research to clinical care.

A review of facial image analysis for delineation of the facial phenotype associated with fetal alcohol syndrome

The facial anomalies associated with fetal alcohol syndrome (FAS), some of which are also present in individuals with less severe forms of the broader category of fetal alcohol spectrum disorders (FASD), are typically identified with the aid of linear distance measurements taken between facial landmarks. Digital facial imaging methods are increasingly being used in syndrome delineation. Distance measurements derived from stereo-photogrammetry and facial surface imaging have been used to study the FAS facial anomalies. Geometric morphometric methods capture the spatial arrangement between landmarks, providing a statistical platform for comparison of facial shapes, and have been shown to hold promise for characterizing the FAS facial shape. We review the progression in the use of imaging and image analysis methods in studies on the facial phenotype associated with FAS.