Development of a new three-dimensional cranial imaging system

Accuracy of 3D facial scans: a comparison of three different scanning system in an in vivo study

BACKGROUND

The aim of the study was to compare the accuracy and reproducibility of three different 3D facial scanning systems, relying, respectively, on stereophotogrammetry, structured light and a smartphone app and camera.

METHODS

Thirty subjects have been scanned with three different facial scanning systems, stereophotogrammetry, structured light and a smartphone app and camera. Linear measurements were compared with direct anthropometries measured on the patient's face, while the study of areas (forehead, tip of the nose, chin, right and left cheek) was evaluated by overlapping scans using the Geomagic Control X program. Statistical analyses were conducted using IBM SPSS v28 software.

RESULTS

The ANOVA test was used to compare linear distances and direct anthropometry measurements, revealing statically significant values for all distances investigated, especially for the Face Hunter scanner, except for the Prn-Pog' distance (p = 0.092). The three facial scans were superimposed pairwise almost the 100 per cent of the overlapping areas fell within the tolerance limits for all three comparisons analysed. The chin was the most accurately reproduced, with no differences among scanners, while the forehead proved to be the least accurately reproduced by all scanners.

CONCLUSIONS

All three acquisition systems proved to be effective in capturing 3D images of the face, with the exception of the Face Hunter scanner, that produced statistically significant differences in linear measurements for the distances Tr-Na' and Zyg-Zyg with respect to direct anthropometric measurements.

An Automated Method of 3D Facial Soft Tissue Landmark Prediction Based on Object Detection and Deep Learning

BACKGROUND

Three-dimensional facial soft tissue landmark prediction is an important tool in dentistry, for which several methods have been developed in recent years, including a deep learning algorithm which relies on converting 3D models into 2D maps, which results in the loss of information and precision.

METHODS

This study proposes a neural network architecture capable of directly predicting landmarks from a 3D facial soft tissue model. Firstly, the range of each organ is obtained by an object detection network. Secondly, the prediction networks obtain landmarks from the 3D models of different organs.

RESULTS

The mean error of this method in local experiments is 2.62±2.39, which is lower than that in other machine learning algorithms or geometric information algorithms. Additionally, over 72% of the mean error of test data falls within ±2.5 mm, and 100% falls within 3 mm. Moreover, this method can predict 32 landmarks, which is higher than any other machine learning-based algorithm.

CONCLUSIONS

According to the results, the proposed method can precisely predict a large number of 3D facial soft tissue landmarks, which gives the feasibility of directly using 3D models for prediction.

Using a 3D asymmetry index as a novel form for capturing complex three-dimensionality in positional plagiocephaly

Positional plagiocephaly (PP) is the most common skull deformity in infants. Different classification systems exist for graduating the degree of PP, but all of these systems are based on two-dimensional (2D) parameters. This limitation leads to several problems stemming from the fact that 2D parameters are used to classify the three-dimensional (3D) shape of the head. We therefore evaluate existing measurement parameters and validate a newly developed 3D parameter for quantifying PP. Additionally, we present a new classification of PP based on a 3D parameter. 210 patients with PP and 50 patients without PP were included in this study. Existing parameters (2D and 3D) and newly developed volume parameters based on a 3D stereophotogrammetry scan were validated using ROC curves. Additionally, thresholds for the new 3D parameter of a 3D asymmetry index were assessed. The volume parameter 3D asymmetry index quantifies PP equally as well as the gold standard of 30° diagonal difference. Moreover, a 3D asymmetry index allows for a 3D-based classification of PP. The 3D asymmetry index can be used to define the degree of PP. It is easily applicable in stereophotogrammetric datasets and allows for comparability both intra- and inter-individually as well as for scientific analysis.

3D Photography to Quantify the Severity of Metopic Craniosynostosis

This study aims to determine the utility of 3D photography for evaluating the severity of metopic craniosynostosis (MCS) using a validated, supervised machine learning (ML) algorithm.

This single-center retrospective cohort study included patients who were evaluated at our tertiary care center for MCS from 2016 to 2020 and underwent both head CT and 3D photography within a 2-month period.

The analysis method builds on our previously established ML algorithm for evaluating MCS severity using skull shape from CT scans. In this study, we regress the model to analyze 3D photographs and correlate the severity scores from both imaging modalities.

14 patients met inclusion criteria, 64.3% male (n = 9). The mean age in years at 3D photography and CT imaging was 0.97 and 0.94, respectively. Ten patient images were obtained preoperatively, and 4 patients did not require surgery. The severity prediction of the ML algorithm correlates closely when comparing the 3D photographs to CT bone data (Spearman correlation coefficient [SCC] r = 0.75; Pearson correlation coefficient [PCC] r = 0.82).

The results of this study show that 3D photography is a valid alternative to CT for evaluation of head shape in MCS. Its use will provide an objective, quantifiable means of assessing outcomes in a rigorous manner while decreasing radiation exposure in this patient population.

Morphometry and displacement analysis of the upper lips following maxillary full-arch implant-supported fixed prostheses: a 3D morphometric study

BACKGROUND

With the emergence of three-dimensional (3D) integration technology, analysis of soft tissue displacement and morphological changes after maxillary full-arch implant-supported fixed prostheses can be performed. The aim of this study was to verify the feasibility of the 3D integration method for constructing the relative position of the prostheses and facial soft tissue, evaluate the displacement and morphological variation of the upper lips after maxillary full-arch implant-supported fixed prostheses.

METHODS

Twenty-five maxillary edentulous patients were recruited in this study. At the time of final prosthesis delivery, the 3D prostheses data and three 3D facial profiles were integrated. After method validation, the 3D position changes of seven soft tissue landmarks were used to reflect the 25 upper lips. The variation of four morphological distances were analyzed to reflect the morphological alteration of the upper lips. Two pairs of dentofacial landmarks were used to analyze the sagittal relative position of the prostheses and soft tissue. The included patients were also grouped to determine the impact of sex, upper lip thickness, and length on lip support changes.

RESULTS

The average distance of the two matched relative reliable forehead regions was only 0.32 mm. The sagittal shifts of labrale superius (LS), stomion (STO), crista philtri left (CPHL) and crista philtri right (CPHR) were 3.44 ± 1.39 mm, 2.52 ± 1.38 mm, 3.04 ± 1.18 mm, and 3.12 ± 1.21 mm, respectively. With the exception of the decrease in the length of subnasale (SN)-LS, the length of cheilion right (CHR)-cheilion left (CHL), CPHR-CPHL, and LS-STO significantly increased. The two pairs of dentofacial landmarks had strong positive movement correlations along the sagittal direction. Patients with thinner and longer lips showed more lip support than those with thicker and shorter lips by a clinically insignificant amount.

CONCLUSIONS

The integration method of 3D facial and dental data showed high repeatability in constructing the dentofacial relative position. The linear equations reflecting dentofacial relative position could aid clinicians in evaluating the restoration effect and estimate the upper lip variation.

Evaluation of 3D Face-Scan images obtained by stereophotogrammetry and smartphone camera

OBJECTIVE

The purpose of this study is to compare and analyze the similarities between three-dimensional images captured by a smartphone camera with depth sensors and a conventional 3dMD Face system.

MATERIALS AND METHODS

Twenty six individuals (16 female, 10 male) were involved in this study, agreed to take part and as such had no paralysis, tics, etc., which may prevent taking the image. Anthropometric points were marked, and plasters were placed on the forehead, upper nasal dorsum and zygoma to determine matching areas. 3D images were captured with a DOF (Depth of Field) camera of a smartphone (iPhone X, Apple Inc. CA, USA) and a 3D imaging system (3dMD, Atlanta, GA, USA). Linear and angular measurements were carried. Overlapping area amounts of matched images and X, Y and Z coordinates of landmarks were compared. For comparison of the data, student t-test and Mann-Whitney U test were used at P<0.05.

RESULTS

Statistically significant changes were found in distance between inner commissures of right and left eye fissure and nasolabial angle. RMS (Root Mean Square) values were found between 0.58 and 1.

CONCLUSION

Images captured with a DOF camera of a smartphone, can be used to record and evaluate 3D soft tissue changes. However, due to the anatomical features of some regions, the deficiency of clear visualization needs improvements.

Postoperative helmet therapy following fronto-orbital advancement and cranial vault remodeling in patients with unilateral coronal synostosis

Out of all the synostotic corrective surgeries, fronto-orbital advancement and cranial vault remodeling for patients with unilateral coronal synostosis is one of the hardest to maintain symmetric and proportional correction without some amount of relapse. Over the course of 20 years operating on these patients, the senior author has made multiple adjustments to compensate for relapse asymmetry, including overcorrection on the affected side, increased points of fixation, periosteal release, and scalp expansion with galeal scoring to minimize tension of the closure. As a result of these interventions, we have seen improved immediate results following surgery. However, we have continued to note clinically significant relapse postoperatively. As such, we have started to implement postoperative helmet therapy (PHT) to help maintain the surgical correction, improve secondary brachycephaly, and increase overall symmetry. PHT is a reasonable low-risk complement to fronto-orbital advancement and cranial vault remolding. Clinically, PHT appears to help minimize relapse and improve overall head symmetry. Further investigation and increased patient enrollment are required to determine the true benefits of PHT in this patient population.

Accuracy and Reliability of Kinect Motion Sensing Input Device’s 3D Models: A Comparison to Direct Anthropometry and 2D Photogrammetry

AIM: This study aims to evaluate the accuracy and reliability of Kinect motion sensing input device’s three-dimensional (3D) models by comparing it with direct anthropometry and digital 2D photogrammetry. MATERIALS AND METHODS: Six profiles and four frontal parameters were directly measured on the faces of 80 participants. The same measurements were repeated using two-dimensional (2D) photogrammetry and (3D) images obtained from Kinect device. Another observer made the same measurements for 30% of the images obtained with 3D technique, and interobserver reproducibility was evaluated for 3D images. Intraobserver reproducibility was evaluated. Statistical analysis was conducted using the paired samples t-test, interclass correlation coefficient, and Bland-Altman limits of agreement. RESULTS: The highest mean difference was 0.0084 mm between direct measurement and photogrammetry, 0.027 mm between direct measurement and 3D Kinect’s models, and 0.018 mm between photogrammetry and 3D Kinect’s. The lowest agreement value was 0.016 in the all parameter between the photogrammetry and 3D Kinect’s methods. Agreement between the two observers varied from 0.999 Sn-Me to 1 with the rest of linear measurements. CONCLUSION: Measurements done using 3D Images obtained from Kinect device indicate that it may be an accurate and reliable imaging method for use in orthodontics. It also provides an easy low-cost 3D imaging technique that has become increasingly popular in clinical settings, offering advantages for surgical planning and outcome evaluation.

Evaluation of the Soft Tissue Changes after Rapid Maxillary Expansion Using a Handheld Three-Dimensional Scanner: A Prospective Study

Facial soft tissue esthetics is a priority in orthodontic treatment, and emerging of the digital technologies can offer new methods to help the orthodontist toward an esthetic outcome. This prospective study aimed to assess the soft tissue changes of the face after six months of retention following Rapid Maxillary Expansion (RME). The sample consisted of 25 patients (13 females, 12 males, mean age: 11.6 years) who presented with unilateral or bilateral posterior crossbite requiring RME, which was performed with a Hyrax expander. 3D facial images were obtained before treatment (T₀) and at the end of a six-month retention period after the treatment (T₁) using a structured-light 3D handheld scanner. Linear and angular measurements were performed and 3D deviation analyses were done for six morphological regions of the face. Significant changes in various areas of the nasal and the upper lip regions were observed. Based on the results of the study and within the limitations of the study, RME with a Hyrax expander results in significant morphological changes of the face after a six-month retention period.

Three-dimensional surface scanning methods in osteology: A topographical and geometric morphometric comparison

Objectives

Three‐dimensional (3D) data collected by structured light scanners, photogrammetry, and computed tomography (CT) scans are increasingly combined in joint analyses, even though the scanning techniques and reconstruction software differ considerably. The aim of the present study was to compare the quality and accuracy of surface models and landmark data obtained from modern clinical CT scanning, 3D structured light scanner, photogrammetry, and MicroScribe digitizer.

Material and methods

We tested 13 different photogrammetric software tools and compared surface models obtained by different methods for four articulated human pelves in a topographical analysis. We also measured a set of 219 landmarks and semilandmarks twice on every surface as well as directly on the dry bones with a MicroScribe digitizer.

Results

Only one photogrammetric software package yielded surface models of the complete pelves that could be used for further analysis. Despite the complex pelvic anatomy, all three methods (CT scanning, 3D structured light scanning, photogrammetry) yielded similar surface representations with average deviations among the surface models between 100 and 200 μm. A geometric morphometric analysis of the measured landmarks showed that the different scanning methods yielded similar shape variables, but data acquisition via MicroScribe digitizer was most prone to error.

Discussion

We demonstrated that three‐dimensional models obtained by different methods can be combined in a single analysis. Photogrammetry proved to be a cheap, quick, and accurate method to generate 3D surface models at useful resolutions, but photogrammetry software packages differ enormously in quality.

Accuracy of an automated method of 3D soft tissue landmark detection

INTRODUCTION

Due to technological advances, the quantification of facial form can now be done via three-dimensional (3D) photographic systems such as stereophotogrammetry. To enable comparison with traditional cephalometry, soft-tissue anatomical landmark definitions have been modified to incorporate the third dimension. Annotating these landmarks manually, however, is still a time-consuming and arduous process.

OBJECTIVE

To develop an automated algorithm to accurately identify anatomical landmarks on three-dimensional soft tissue images.

METHODS

Thirty 3dMD images were selected from a private orthodontic practice consisting of 15 males and 15 females between 9 and 17 years of age. The soft-tissue 3D images were aligned along a reference plane to setup a Cartesian coordinate system. Screened by 2 observers, 21 landmarks were manually annotated and their coordinates defined. An automated landmark identification algorithm, based on their anatomical definitions, was developed to compare the landmark validity against the manually identified counterpart.

RESULTS

Twenty-one landmarks were analysed in detail. Inter-observer and intra-observer reliability using ICC was >0.9. The average difference and standard deviation between manual and automated methods for all landmarks was 3.2 and 1.64 mm, respectively. Sixteen out of twenty-one landmarks had a mean difference less than 4 mm. The landmarks of greatest agreement (≤2 mm) were mainly in the midline: pronasale, subnasale, subspinale, labiale superius, stomion, with the exception of chelion right. Five linear facial measurements were found to have moderate to good agreement between the manual and automated identification methods.

CONCLUSIONS

The developed algorithm was determined to be clinically relevant in the detection of midsagittal landmarks and associated measurements within the studied sample of adolescent Caucasian subjects.

[Validation of the digital integration technology for evaluating the nasolabial morphology variation after the cross-arch fixed restoration of maxillary implant-supported prostheses]

OBJECTIVE

To explore the applicability of integration between three-dimensional (3D) facial and dental data to evaluate the nasolabial morphology variation before and after the cross-arch fixed restoration of the maxillary implant-supported prostheses.

METHODS

Twelve patients (4 women and 8 men), mean age (54.82±5.50) years (from 45 to 62 years) referred to the Department of Oral Implan-tology, Peking University School and Hospital of Stomatology, were selected and diagnosed with edentulous maxilla. For all the patients, 4 to 6 implants were inserted into the maxilla. Six months later, the final cross-arch fixed prostheses were delivered. The 3D facial images were collected before and after the final restoration. The 3D data of prostheses were also captured. All the 3D data were registered and measured in the same coordinate system. Then the displacement of all the landmarks [cheilion left (CHL), cheilion right (CHR), crista philtri left (CPHL), crista philtri right (CPHR), labrale supe-rius (LS), subnasale (SN), stomion (STO), upper incisor (UI), upper flange border of the prostheses (F-point, F)], and the variation of the distances between these landmarks (SN-LS, CPHR-CPHL, CHR-CHL, LS-STO) were analyzed and compared.

RESULTS

The consistency test among three measurements of the length of F-SN indicated that the integration method of the dental prostheses and soft tissue had the good repetitiveness, ICC=0.983 (95%CI: 0.957-0.995). After wearing the final cross-arch maxillary implant-supported prostheses, all the landmarks on the soft tissue moved forward. The nasal base area changed minimally, and the shift of SN in the sagittal direction was only (0.61±0.44) mm. But the sagittal shift of LS was (3.12±1.38) mm. In the vertical direction, SN, LS, CPHL, and CPHR moved upward. But STO, CHL, and CHR moved downward a little. Except for the slight decrease of the length of philtrum (SN-LS), the length of CHL-CHR, CPHL-CPHR, and the height of upper lip were increased together (P < 0.01). In the direction of Z axis, the strong correlations were found not only between the movements of SN and F (r=0.904 3) but also between the movements of LS and UI (r=0.958 4).

CONCLUSION

The integration method of 3D facial and dental data showed good repetitiveness. And the strong correlations between the landmarks of prostheses and nasolabial soft tissue in the sagittal direction were found by this new method.

Helmet Treatment of Infants With Deformational Brachycephaly

Deformation of the cranium in infancy represents a spectrum of deformity, ranging from severe asymmetric yet proportional distortion of the skull in plagiocephaly, to nearly symmetric yet disproportional distortion in brachycephaly. As such, the condition is best described as deformational plagiocephaly-brachycephaly with isolated plagiocephaly and/or isolated brachycephaly being at either ends of the spectrum. Due to its symmetric appearance, deformational brachycephaly is often incorrectly dismissed as being less concerning, and it has sometimes erroneously been reported that brachycephaly cannot be treated successfully with a cranial orthosis. We prospectively report on 4205 infants with isolated deformational brachycephaly treated with a cranial orthosis from 2013 to 2017. These results demonstrate that the orthosis is successful in the treatment of deformational brachycephaly with an 81.4% improvement toward normal (95.0 to 89.4) in cephalic index. We furthermore demonstrate that entrance age influences treatment results, with younger infants demonstrating both improved outcomes and shorter treatment times.

Quantification of Plagiocephaly and Brachycephaly in Infants Using a Digital Photographic Technique

Objectives

The aims of the study were: (1) to develop a technique to quantify plagiocephaly that is safe, accurate, objective, easy to use, well tolerated, and inexpensive; and (2) to compare this method with tracings from a flexicurve ruler.

Design

A case-control study of 31 case infants recruited from outpatient plagiocephaly clinics and 29 control infants recruited from other pediatric outpatient clinics.

Participants

Infants in the study had been diagnosed with nonsynostotic plagiocephaly or brachycephaly and were between 2 and 12 months old.

Interventions

Infants’ head shapes were measured using (a) digital photographs of a head circumference band and (b) a flexicurve ruler. Flexicurve tracings were scanned, and both the digital photos and the scanned flexicurve tracings were analyzed using a custom-written computer program.

Main Outcome Measures

The oblique cranial length ratio was used to quantify cranial asymmetry, and the cephalic index was used to quantify the degree of brachycephaly.

Results

The infants tolerated the photo technique better than the flexicurve. Also, mothers preferred the photo technique. There was less within-subject variance for the photos than for the flexicurve measurements. The results suggested that an oblique cranial length ratio of ≥ 106% can define plagiocephaly and that a cephalic index of ≥ 93% can define brachycephaly.

Conclusions

The photographic technique was better accepted and more repeatable than the flexicurve measuring system. We propose that “normal” head shape is indicated in infants with both an oblique cranial length ratio of less than 106% and a cephalic index of less than 93%.

Comparison of Plaster Casting with Three-Dimensional Cranial Imaging

Objective

The development of a new cranial imaging system to capture a three-dimensional (3D) model of an infant's head has been previously reported. The accuracy of this new system has been independently established. However, before replacing the traditional plaster casting technique, the two methods require a comparison to ensure that the models they produce are equivalent.

Methods

Ten sequential infants were digitized by the 3D imaging system and the plaster casting technique following previously reported protocols. The cast models were also digitized so they could be compared with the digitized images. The two models (3dImage and Cast) were then imported into dimensional analysis software and aligned and registered with well-established registration algorithms. Difference maps that identified the variation between the two surfaces were generated for each pair, and descriptive statistics of these differences were recorded.

Results

The mean difference between the cast and the digitized models was 0.052 mm (standard deviation = 0.988), with a root mean square (RMS) difference of 1.028 mm. Two-dimensional slices obtained from the registered 3D surfaces demonstrated excellent agreement between the cranial contours.

Conclusions

In this investigation, the 3D models created by the new imaging system were found to be within 1.0 mm RMS of the models created by the plaster casting technique. Two-dimensional cranial contours demonstrated excellent agreement between the two methods. The results of this investigation confirmed that the new cranial imaging system and the traditional plaster casting technique yield equivalent models.

A novel computer system for the evaluation of nasolabial morphology, symmetry and aesthetics after cleft lip and palate treatment. Part 1: General concept and validation

PURPOSE

The need for a widely accepted method suitable for a multicentre quantitative evaluation of facial aesthetics after surgical treatment of cleft lip and palate (CLP) has been emphasized for years. The aim of this study was to validate a novel computer system 'Analyse It Doc' (A.I.D.) as a tool for objective anthropometric analysis of the nasolabial region.

MATERIALS AND METHODS

An indirect anthropometric analysis of facial photographs was conducted with the A.I.D. system and Adobe Photoshop/ImageJ software. Intra-rater and inter-rater reliability and the time required for the analysis were estimated separately for each method and compared.

RESULTS

Analysis with A.I.D. system was nearly 10-fold faster than that with the reference evaluation method. The A.I.D. system provided strong inter-rater and intra-rater correlations for linear, angular and area measurements of the nasolabial region, as well as a significantly higher accuracy and reproducibility of angular measurements in submental view. No statistically significant inter-method differences were found for other measurements.

CONCLUSIONS

The hereby presented novel computer system is suitable for simple, time-efficient and reliable multicenter photogrammetric analyses of the nasolabial region in CLP patients and healthy subjects.

The 3D Tele Motion Tracking for the Orthodontic Facial Analysis

Aim. This study aimed to evaluate the reliability of 3D-TMT, previously used only for dynamic testing, in a static cephalometric evaluation. Material and Method. A group of 40 patients (20 males and 20 females; mean age 14.2 ± 1.2 years; 12–18 years old) was included in the study. The measurements obtained by the 3D-TMT cephalometric analysis with a conventional frontal cephalometric analysis were compared for each subject. Nine passive markers reflectors were positioned on the face skin for the detection of the profile of the patient. Through the acquisition of these points, corresponding plans for three-dimensional posterior-anterior cephalometric analysis were found. Results. The cephalometric results carried out with 3D-TMT and with traditional posterior-anterior cephalometric analysis showed the 3D-TMT system values are slightly higher than the values measured on radiographs but statistically significant; nevertheless their correlation is very high. Conclusion. The recorded values obtained using the 3D-TMT analysis were correlated to cephalometric analysis, with small but statistically significant differences. The Dahlberg errors resulted to be always lower than the mean difference between the 2D and 3D measurements. A clinician should use, during the clinical monitoring of a patient, always the same method, to avoid comparing different millimeter magnitudes.

Effects of rapid maxillary expansion on facial soft tissues : Deviation analysis on three-dimensional images

OBJECTIVE

Changes in soft tissue in various morphological regions of the face immediately after rapid maxillary expansion (RME) were examined using three-dimensional (3D) deviation analyses.

PATIENTS AND METHODS

A total of 50 patients were included in the study; 25 patients (11 female and 14 male) presented with a unilateral or bilateral posterior crossbite malocclusion requiring RME. In addition, 25 patients (13 female and 12 male) were included as a control group. The mean ages of the study group and control group were 9.8 years (range 8.1-12.6 years) and 9.6 years (range 8.3-12.2 years), respectively. The 3D stereophotogrammetric images acquired immediately before the appliance was cemented and after expansion had been completed in the treatment group were compared using Rapidform software. The 3D deviation analyses were made for the complete face and in the upper and lower face, upper and lower lips and nose regions. The amount of negative and positive deviations and the mean deviations were examined on the facial meshes for the 95th percentiles.

RESULTS

Immediately after RME, the mean absolute deviation over the complete face was 0.54 ± 0.16 mm. The mean change for the upper face was 0.42 ± 0.17 mm (mean positive deviation: 0.37 ± 0.17 mm; mean negative deviation: -0.48 ± 0.18 mm). The mean absolute deviation was 0.62 ± 0.28 mm in the upper lip and 0.60 ± 0.34 mm in the lower lip. In the nose area, the absolute deviation was 0.41 ± 0.21 mm (mean positive deviation: 0.39 ± 0.16 mm; mean negative deviation: -0.43 ± 0.26 mm).

CONCLUSIONS

Changes in facial soft tissues in the upper face, lower face, nasal soft tissues, and lower and upper lip regions were observed after RME.

Evaluation of Facial Volume Changes after Rejuvenation Surgery Using a 3-Dimensional Camera

BACKGROUND

Surgical rejuvenation alters facial volume distribution to achieve more youthful aesthetic contours. These changes are routinely compared subjectively. The introduction of 3-dimensional (3D) stereophotogrammetry provides a novel method for measuring and comparing surgical results.

OBJECTIVES

We sought to quantify how specific facial areas are changed after rejuvenation surgery using the 3D camera.

METHODS

Patients undergoing facial rejuvenation were imaged preoperatively and postoperatively with 3D stereophotogrammetry. Images were registered using facial surface landmarks unaltered by surgery. Colorimetric 3D analysis depicting postoperative volume changes was performed utilizing the 3D imaging software and quantitative volume measurements were constructed.

RESULTS

Nine patients who underwent combined facelift procedures and fat grafting were evaluated. Median time for postoperative imaging was 4.8 months. Positive changes in facial volume occurred in the forehead, temples, and cheeks (median changes, 0.9 mL ± 4.3 SD; 0.8 mL ± 0.47 SD; and 1.4 mL ± 1.6 SD, respectively). Negative changes in volume occurred in the nasolabial folds, marionette basins, and neck/submental regions (median changes, -1.0 mL ± 0.37 SD; -0.4 mL ± 0.9 SD; and -2.0 mL ± 4.3 SD, respectively).

CONCLUSIONS

The technique of 3D stereophotogrammetry provides a tool for quantifying facial volume distribution after rejuvenation procedures. Areas of consistent volume increase include the forehead, temples, and cheeks; areas of negative volume change occur in the nasolabial folds, marionette basins, and submental/chin regions. This technology may be utilized to better understand the dynamic changes that occur with facial rejuvenation and quantify longevity of various rejuvenation techniques.

LEVEL OF EVIDENCE

4 Diagnostic.

Development of a Three-Dimensional Hand Model Using Three-Dimensional Stereophotogrammetry: Assessment of Image Reproducibility

Purpose

Using three-dimensional (3D) stereophotogrammetry precise images and reconstructions of the human body can be produced. Over the last few years, this technique is mainly being developed in the field of maxillofacial reconstructive surgery, creating fusion images with computed tomography (CT) data for precise planning and prediction of treatment outcome. Though, in hand surgery 3D stereophotogrammetry is not yet being used in clinical settings.

Methods

A total of 34 three-dimensional hand photographs were analyzed to investigate the reproducibility. For every individual, 3D photographs were captured at two different time points (baseline T0 and one week later T1). Using two different registration methods, the reproducibility of the methods was analyzed. Furthermore, the differences between 3D photos of men and women were compared in a distance map as a first clinical pilot testing our registration method.

Results

The absolute mean registration error for the complete hand was 1.46 mm. This reduced to an error of 0.56 mm isolating the region to the palm of the hand. When comparing hands of both sexes, it was seen that the male hand was larger (broader base and longer fingers) than the female hand.

Conclusions

This study shows that 3D stereophotogrammetry can produce reproducible images of the hand without harmful side effects for the patient, so proving to be a reliable method for soft tissue analysis. Its potential use in everyday practice of hand surgery needs to be further explored.

Accuracy and reliability of 3D stereophotogrammetry: A comparison to direct anthropometry and 2D photogrammetry

OBJECTIVE

To evaluate the accuracy of three-dimensional (3D) stereophotogrammetry by comparing it with the direct anthropometry and digital photogrammetry methods. The reliability of 3D stereophotogrammetry was also examined.

MATERIALS AND METHODS

Six profile and four frontal parameters were directly measured on the faces of 80 participants. The same measurements were repeated using two-dimensional (2D) photogrammetry and 3D stereophotogrammetry (3dMDflex System, 3dMD, Atlanta, Ga) to obtain images of the subjects. Another observer made the same measurements for images obtained with 3D stereophotogrammetry, and interobserver reproducibility was evaluated for 3D images. Both observers remeasured the 3D images 1 month later, and intraobserver reproducibility was evaluated. Statistical analysis was conducted using the paired samples t-test, intraclass correlation coefficient, and Bland-Altman limits of agreement.

RESULTS

The highest mean difference was 0.30 mm between direct measurement and photogrammetry, 0.21 mm between direct measurement and 3D stereophotogrammetry, and 0.5 mm between photogrammetry and 3D stereophotogrammetry. The lowest agreement value was 0.965 in the Sn-Pro parameter between the photogrammetry and 3D stereophotogrammetry methods. Agreement between the two observers varied from 0.90 (Ch-Ch) to 0.99 (Sn-Me) in linear measurements. For intraobserver agreement, the highest difference between means was 0.33 for observer 1 and 1.42 mm for observer 2.

CONCLUSIONS

Measurements obtained using 3D stereophotogrammetry indicate that it may be an accurate and reliable imaging method for use in orthodontics.

Reciprocal Relationship between Head Size, an Autism Endophenotype, and Gene Dosage at 19p13.12 Points to AKAP8 and AKAP8L

Microcephaly and macrocephaly are overrepresented in individuals with autism and are thought to be disease-related risk factors or endophenotypes. Analysis of DNA microarray results from a family with a low functioning autistic child determined that the proband and two additional unaffected family members who carry a rare inherited 760 kb duplication of unknown clinical significance at 19p13.12 are macrocephalic. Consideration alongside overlapping deletion and duplication events in the literature provides support for a strong relationship between gene dosage at this locus and head size, with losses and gains associated with microcephaly (p=1.11x10(-11)) and macrocephaly (p=2.47x10(-11)), respectively. Data support A kinase anchor protein 8 and 8-like (AKAP8 and AKAP8L) as candidate genes involved in regulation of head growth, an interesting finding given previous work implicating the AKAP gene family in autism. Towards determination of which of AKAP8 and AKAP8L may be involved in the modulation of head size and risk for disease, we analyzed exome sequencing data for 693 autism families (2591 individuals) where head circumference data were available. No predicted loss of function variants were observed, precluding insights into relationship to head size, but highlighting strong evolutionary conservation. Taken together, findings support the idea that gene dosage at 19p13.12, and AKAP8 and/or AKAP8L in particular, play an important role in modulation of head size and may contribute to autism risk. Exome sequencing of the family also identified a rare inherited variant predicted to disrupt splicing of TPTE / PTEN2, a PTEN homologue, which may likewise contribute to both macrocephaly and autism risk.

Virtual techniques for designing and fabricating a retainer

The purpose of this article was to report a procedure for using 3-dimensional cone-beam computed tomography imaging, computer-aided design, computer-aided manufacturing, and rapid prototyping to design and produce a retainer.

Orthodontic soft-tissue parameters: a comparison of cone-beam computed tomography and the 3dMD imaging system

INTRODUCTION

Orthodontists rely heavily on soft-tissue analysis to determine facial esthetics and treatment stability. The aim of this retrospective study was to determine the equivalence of soft-tissue measurements between the 3dMD imaging system (3dMD, Atlanta, Ga) and the segmented skin surface images derived from cone-beam computed tomography.

METHODS

Seventy preexisting 3dMD facial photographs and cone-beam computed tomography scans taken within minutes of each other for the same subjects were registered in 3 dimensions and superimposed using Vultus (3dMD) software. After reliability studies, 28 soft-tissue measurements were recorded with both imaging modalities and compared to analyze their equivalence. Intraclass correlation coefficients and Bland-Altman plots were used to assess interexaminer and intraexaminer repeatability and agreement. Summary statistics were calculated for all measurements. To demonstrate equivalence of the 2 methods, the difference needed a 95% confidence interval contained entirely within the equivalence limits defined by the repeatability results.

RESULTS

Statistically significant differences were reported for the vermilion height, mouth width, total facial width, mouth symmetry, soft-tissue lip thickness, and eye symmetry.

CONCLUSIONS

There are areas of nonequivalence between the 2 imaging methods; however, the differences are clinically acceptable from the orthodontic point of view.

Nostril Morphometry Evaluation before and after Cleft Lip Surgical Correction: Clinical Evidence

Introduction The purpose to this work is to review systematically the morphological changes of the nostrils of patients undergoing surgery for correction of cleft lip and identify in the literature the issues involved in the evaluation of surgical results in this population.

Review of Literature A review was conducted, searching for clinical evidence from MEDLINE. The search occurred in January 2012. Selection criteria included original articles and research articles on individual subjects with cleft lip or cleft palate with unilateral nostril anthropometric measurements before and after surgical correction of cleft lip and measurements of soft tissues. There were 1,343 articles from the search descriptors and free terms. Of these, five articles were selected.

Discussion Most studies in this review evaluated children in Eastern countries, using different measurement techniques but with the aid of computers, and showed improved nostril asymmetry postoperatively compared with preoperatively.

Conclusion There is a reduction of the total nasal width postoperatively compared with preoperative measurements in patients with cleft lip.

Three-dimensional laser scanner evaluation of facial soft tissue changes after LeFort I advancement and rhinoplasty surgery: patients with cleft lip and palate vs patients with nonclefted maxillary retrognathic dysplasia (control group)

OBJECTIVE

The aim of this study was to analyze the differences in facial soft tissue changes, despite the same extent of upper jaw forward movement, between patients with unilateral cleft lip and palate (uCLP) and those without, after LeFort I osteotomy and secondary rhinoplasty.

STUDY DESIGN

Twelve patients with maxillary retrognathic dysplasia and nose deformity were divided in 2 groups, A (uCLP) and B (control), and compared on the basis of the same maxillary advancement. Cephalometry and 3D mean facial model of groups A and B were obtained before and after surgery. Linear and angular measurements were calculated.

RESULTS

Upper vermilion and alar base remained unchanged in group A but increased in group B. In both groups, symmetry of the nasal base was improved, and an increase of the sagittal projection of the lips was observed.

CONCLUSIONS

3D analysis showed that surgical procedures for uCLP can provide a satisfactory aesthetic outcome, but some differences are evident in comparison with the control group.

Outcome analysis after helmet therapy using 3D photogrammetry in patients with deformational plagiocephaly: the role of root mean square

Deformational plagiocephaly (DP) is a multifactorial non-synostotic cranial deformity with a reported incidence as high as 1 in 7 infants in North America. Treatment options have focused on non-operative interventions including head repositioning and the use of an orthotic helmet device. Previous studies have used linear and two dimensional outcome measures to assess changes in cranial symmetry after helmet therapy. Our objective was to demonstrate improvement in head shape after treatment with a cranial molding helmet by using Root Mean Square (RMS), a measure unique to 3D photogrammetry, which takes into account both changes in volume and shape over time. Three dimensional photographs were obtained before and after molding helmet treatment in 40 infants (4-10 months old) with deformational plagiocephaly. Anatomical reference planes and measurements were recorded using the 3dMD Vultus(®) analysis software. RMS was used to quantify symmetry by superimposing left and right quadrants and calculating the mean value of aggregate distances between surfaces. Over 95% of the patients demonstrated an improvement in symmetry with helmet therapy. Furthermore, when the sample of infants was divided into two treatment subgroups, a statistically significant correlation was found between the age at the beginning of treatment and the change in the RMS value. When helmet therapy was started before 7 months of age a greater improvement in symmetry was seen. This work represents application of the technique of RMS analysis to demonstrate the efficacy of treatment of deformational plagiocephaly with a cranial molding helmet.

Facial Scanning With a Digital Camera: A Novel Way of Screening for Primary Angle Closure

PURPOSE

We hypothesize that patients with primary angle closure (PAC) have common significant facial characteristics that set them apart from an age-matched, sex-matched, and race-matched control population. The primary objective of this study was to test whether a 3-dimensional (3D) camera could pick up these differences in order to differentiate PAC patients from controls.

PATIENTS

A total of 55 patients with PAC and 38 controls were included in the study.

MATERIALS AND METHODS

Cases and controls had their facial photographs taken using a 3-dimensional digital camera (3dMdFace System). The facial features in the captured photographs were analyzed using a computer software (Neural Network Toolbox). A regression formula was devised to show whether these facial parameters could be used to distinguish between patients and controls.

RESULTS

Thirteen facial parameters were measured, and using a regression formula and neural network classification we were able to mathematically distinguish patients from controls using this method of screening.

CONCLUSIONS

PAC patients have distinct facial features that may be differentiated from those of normal individuals mathematically using 3D photography. There is potential for this 3D facial scanning technology in screening for PAC in the general population.

Methods to quantify soft-tissue based facial growth and treatment outcomes in children: a systematic review

Context

Technological advancements have led craniofacial researchers and clinicians into the era of three-dimensional digital imaging for quantitative evaluation of craniofacial growth and treatment outcomes.

Objective

To give an overview of soft-tissue based methods for quantitative longitudinal assessment of facial dimensions in children until six years of age and to assess the reliability of these methods in studies with good methodological quality.

Data Source

PubMed, EMBASE, Cochrane Library, Web of Science, Scopus and CINAHL were searched. A hand search was performed to check for additional relevant studies.

Study Selection

Primary publications on facial growth and treatment outcomes in children younger than six years of age were included.

Data Extraction

Independent data extraction by two observers. A quality assessment instrument was used to determine the methodological quality. Methods, used in studies with good methodological quality, were assessed for reliability expressed as the magnitude of the measurement error and the correlation coefficient between repeated measurements.

Results

In total, 47 studies were included describing 4 methods: 2D x-ray cephalometry; 2D photography; anthropometry; 3D imaging techniques (surface laser scanning, stereophotogrammetry and cone beam computed tomography). In general the measurement error was below 1 mm and 1° and correlation coefficients range from 0.65 to 1.0.

Conclusion

Various methods have shown to be reliable. However, at present stereophotogrammetry seems to be the best 3D method for quantitative longitudinal assessment of facial dimensions in children until six years of age due to its millisecond fast image capture, archival capabilities, high resolution and no exposure to ionizing radiation.

Outcomes in facial aesthetics in cleft lip and palate surgery: a systematic review

BACKGROUND

While there are internationally validated outcome measures for speech and facial growth in cleft lip and palate patients, there is no such internationally accepted system for assessing outcomes in facial aesthetics.

METHOD

A systematic critical review of the scientific literature from the last 30 years using PUBMED, Medline and Google Scholar was conducted in-line with the PRISMA statement recommendations. This encompassed the most relevant manuscripts on aesthetic outcomes in cleft surgery in the English language.

RESULTS

Fifty-three articles were reviewed. Four main means of determining outcome measures were found: direct clinical assessment, clinical photograph evaluation, clinical videographic assessment and three-dimensional evaluation. Cropped photographs were more representative than full face. Most techniques were based on a 5-point scale, evolving from the Asher-McDade system. Multiple panel-based assessments compared scores from lay or professional raters, the results of which were not statistically significant. Various reports based on cohorts were poorly matched for gender, age, clinical condition and ethnicity, making their results difficult to reproduce.

CONCLUSIONS

The large number of outcome measure rating systems identified, suggests a lack of consensus and confidence as to a reliable, validated and reproducible scoring system for facial aesthetics in cleft patients. Many template and lay panel scoring systems are described, yet never fully validated. Advanced 3D imaging technologies may produce validated outcome measures in the future, but presently there remains a need to develop a robust method of facial aesthetic evaluation based on standardised patient photographs. We make recommendations for the development of such a system.

Teaching 3D sculpting to facial plastic surgeons

This article describes the authors' course, which takes facial plastic surgeons through specific exercises to demonstrate the esthetic impact of 3D manipulations of the nose and face. The course components are described, which include 3D assessment, exercises in manual dexterity, and improving imagination in sculpting facial and nasal features for the optimal esthetic result and match to a given facial shape. The overlap and relationship between a course in 3D sculpting in facial plastic surgery and current 3D tools for design and image analysis being used for facial plastic surgery are discussed.

Accuracy and precision of a 3D anthropometric facial analysis with and without landmark labeling before image acquisition

OBJECTIVE

To determine the influence of landmark labeling on the accuracy and precision of an indirect facial anthropometric technique.

MATERIALS AND METHODS

Eighteen standard linear craniofacial measurements were obtained from 10 adults using the 3dMDface system, with landmarks labeled (Labeled_3D) and without landmarks labeled (Unlabeled_3D) before image acquisition, and these were compared with direct anthropometry (Caliper). Images were acquired twice in two different sessions 1 week apart (T1 and T2). Accuracy and precision were determined by comparing mean measurement values and absolute differences between the three methods.

RESULTS

Mean measurements derived from three-dimensional (3D) images and direct anthropologic measurements were mostly similar. However, statistically significant differences (P < .01) were noted for seven measurements in Labeled_3D and six measurements in Unlabeled_3D. The magnitudes of these differences were clinically insignificant (<2 mm). In terms of precision, results demonstrated good reproducibility for both methods, with a tendency toward more precise values in Labeled_3D, when compared with the other two techniques (P < .05). We found that Labeled_3D provided the most precise values, Unlabeled_3D produced less precise measurements, and Caliper was the least capable of generating precise values.

CONCLUSIONS

Overall, soft tissue facial measurement with the 3dMDface system demonstrated similar accuracy and precision with traditional anthropometry, regardless of landmarking before image acquisition. Larger disagreements were found regarding measurements involving ears and soft tissue landmarks without distinct edges. The 3dMDface system demonstrated a high level of precision, especially when facial landmarks were labeled.

Variation of the face in rest using 3D stereophotogrammetry

To evaluate treatment outcomes following oral and maxillofacial surgery, pre- and post-treatment three-dimensional (3D) photographs of the patient's face can assessed, but this procedure is accurate only if the face is captured with the same facial expression every time. The purpose of this prospective study was to determine variations in the face at rest; 100 3D photographs of the same individual were acquired at different times. Initially, 50 3D photographs were obtained; 25 using a wax bite to ensure similar occlusion between subsequent photographs and 25 without wax bite. This procedure was repeated 6 weeks later. Variation of the face at rest was computed. The influence of time and wax bite was investigated. Different anatomical regions were investigated separately. A mean variation of 0.25 mm (0.21-0.27 mm) was found (standard deviation 0.157 mm). No large differences were found between different time points or use of wax bite. Regarding separate anatomical regions, there were small variations in the nose and forehead regions; the largest variations were found in the mouth and eyes. This study showed small overall variation within the face at rest. In conclusion, different 3D photographs can be reproduced accurately and used in a clinical setting for treatment follow-up and evaluation.

3-dimensional analyses of outcomes following secondary treatment of unilateral cleft lip nose deformity

OBJECTIVE

To analyze the 3-dimensional nasal forms after secondary treatment of unilateral cleft lip nose deformity.

PATIENTS AND METHODS

Thirteen Japanese adolescents with severe nose deformity associated with unilateral complete cleft lip with/without palate underwent definitive nose correction at the Department of Oral and Maxillofacial Surgery, Kagoshima University Hospital, and were followed for 1 to 3 years. Twenty healthy Japanese age-matched adolescents were included as controls. All patients were treated by open rhinoplasty through bilateral reverse-U incision and transcolumellar incision, correction of the columellar base with/without septoplasty, columellar strut graft, and medial-upward advancement of nasolabial components with vestibular expansion using a free mucosal graft. Pre- and postoperative nasal forms were measured using a 3-dimensional noncontact laser scanner. Angular and linear measurements, symmetry of the alar groove arch, and deviation of the nasal midline were analyzed.

RESULTS

Comparison of pre- with postoperative 3-dimensional nasal forms showed that postoperative nasal height was significantly increased (P < .01) but still shorter than that of controls. The significant preoperative differences in the nasal dorsal angle (P < .05) and bilateral alar groove arch (P < .01) disappeared after the operation. The deviation of the nasal midline was improved in the lower half of the nose (P < .05) postoperatively. There were no serious complications in any patients.

CONCLUSIONS

These surgical procedures can provide a symmetric and protruded nasal form, but there remain some differences between postoperative patients and healthy Japanese subjects.

Picture perfect? Reliability of craniofacial anthropometry using three-dimensional digital stereophotogrammetry

BACKGROUND

Quantification of facial characteristics is important for research in dysmorphology, otolaryngology, oral and maxillofacial, and plastic surgical disciplines, among others. Three-dimensional surface imaging systems offer a quick and practical method for quantifying craniofacial variation and appear to be highly reliable. However, some sources of measurement error have not yet been thoroughly evaluated.

METHODS

The authors assessed the reliability of using stereophotogrammetry for measuring craniofacial characteristics in 40 individuals, including 20 without craniofacial conditions and 20 with 22q11.2 deletion syndrome. The authors recruited staff and relatives of staff, and individuals with a laboratory-confirmed 22q11.2 deletion. Thirty anthropometric measurements were obtained on participants and on three-dimensional images.

RESULTS

Intrarater and interrater reliability for most interlandmark distances on three-dimensional images had intraclass correlation coefficients greater than 95 percent, mean absolute differences of less than 1 mm, relative error measurement less than 5, and technical error of measurement less than 1 mm. The Pearson correlation coefficients of greater than 0.9 for most distances suggest high intermethod reliability between direct and image-based measurements. Three-dimensional image-based measurements were systematically larger for the head length and width, forehead, and skull base widths, and upper and lower facial widths.

CONCLUSIONS

This study provides further evidence of the high reliability of three-dimensional imaging systems for several craniofacial measurements, including landmarks and interlandmark distances not included in previous studies. The authors also discuss possible errors introduced with palpable landmarks and when working with less compliant participants, such as children. The authors offer guidelines for establishing protocols that can be tailored to each population and research question to maximize the accuracy of image-based measurements.

A 3D digital medical photography system in paediatric medicine

In 2004, traditional clinical photography services at the Educational Resource Centre were extended using new technology. This paper describes the establishment of a 3D digital imaging system in a paediatric setting at the Royal Children's Hospital, Melbourne.

Management of facial asymmetry

Asymmetries of the craniofacial region encompass a multitude of diverse and potentially complex abnormalities that may be the result of numerous causes. The expression and degree of asymmetry for a given condition, although a highly variable process, is the ultimate determinant of the nature of its treatment. This article highlights some of the key features and treatment strategies for various common facial asymmetries.

Validity and reliability of craniofacial anthropometric measurement of 3D digital photogrammetric images

BACKGROUND

Direct anthropometry performed during a patient examination is the standard technique for quantifying craniofacial dysmorphology, as well as for surgical planning and outcome assessment. Several new technologies have been designed to computerize anthropometric measurements, including three-dimensional (3D) digital photogrammetry. These digital systems have the advantage of acquiring patient craniofacial surface images quickly and noninvasively. Before morphometry using digital photogrammetry can be applied in clinical and research practice, it must be assessed against direct anthropometry.

OBJECTIVE

To evaluate the validity and reliability of facial anthropometric linear distances imaged by 3D digital photogrammetry with respect to direct anthropometry. DESIGN, SETTING, PARTICIPANTS, MEASURES: Standard craniofacial distances were directly measured twice on 20 normal adult volunteers. Craniofacial surfaces were also imaged using the 3dMDface digital photogrammetry system, and distances were digitally measured twice for each subject. Validity measures of accuracy and bias (for direct versus digital measurements) and reproducibility measures of precision and test-retest reliability (for repeated sets of digital measurements) were computed.

RESULTS

Seventeen of the 18 direct measurements correlated highly with digital values (mean r = 0.88). The correlation for one measurement (upper prolabial width) was not statistically significant. The overall precision of all 17 digital measurements was less than 1 mm, and the reliability was high (mean r = 0.91).

CONCLUSIONS

Craniofacial anthropometry using the 3dMDface System is valid and reliable. Digital measurements of upper prolabial width may require direct marking, prior to imaging, to improve landmark identification.

Stereolithography for Craniofacial Surgery

Advances in computer technology have aided in the diagnostic and clinical management of complex congenital craniofacial deformities. The use of stereolithographic models has begun to replace traditional milled models in the treatment of craniofacial deformities. Research has shown that stereolithography models are highly accurate and provide added information in treatment planning for the correction of craniofacial deformities. These include the added visualization of the complex craniofacial anatomy and preoperative surgical planning with a highly accurate three-dimensional model. While the stereolithographic process has had a beneficial impact on the field of craniofacial surgery, the added cost of the procedure continues to be a hindrance to its widespread acceptance in clinical practice. With improved technology and accessibility the utilization of stereolithography in craniofacial surgery is expected to increase. This review will highlight the development and current usage of stereolithography in craniofacial surgery and provide illustration of it use.

Reconstruction of facial morphology from laser scanned data. Part I: reliability of the technique

OBJECTIVES

The aim of this study was to evaluate the effects of scanning parameters on the precision of the data acquired using a facial laser scanner and to assess the reliability of automatic model recording in humans.

METHODS

Data were acquired using a laser scanner (Cyberware 3030RGB); analysis and measurements were performed with Rapid Form 2004 software. A mannequin and six volunteers were scanned to investigate the effects of environmental conditions, positioning, head orientation, and software procedures. Precision and accuracy of the data were evaluated comparing six linear measures calculated on scanned data with those obtained directly. Two sessions with different head inclination were performed. The reliability of repeated scans was also assessed measuring the distance between the surfaces reconstructed from two separate scans of the same subject, at 12 anatomical points, in 5 subjects, during two sessions using a different head inclination. Differences were analysed using paired t-tests or analysis of variance (ANOVA).

RESULTS

The accuracy of scanning was +/-0.65 mm. The development of a specific protocol resulted in a mean scanning error of 1-1.2 mm and a recording error of 0.3-0.4 mm on repeated scans of human subjects.

CONCLUSIONS

This study indicates that scanning of the human face may be hampered by errors and artefacts, mainly due to movements. While the effect of trembling and involuntary movements during the exam may be minimized using faster scanning devices, comparative observation over time may be affected by unreal differences due to the uncertainty of facial expression. The overall error is, however, in the range useful for most clinical studies.

Neurodevelopmental implications of "deformational" plagiocephaly

Over the past decade there has been a dramatic increase in referrals to specialty clinics, craniofacial centers, plastic surgeons, and neurosurgeons for assessment and treatment of deformational plagiocephaly (DP). Though considered a medically benign condition, preliminary reports suggest that DP may be associated with developmental problems. However, mechanisms to account for this association have not been hypothesized or empirically tested. Although treatment justifications often center on prevention of atypical appearance, little is known about the cosmetic outcomes of treated and untreated children. In this review we hypothesize different etiological pathways linking DP with neurodevelopment (e.g., environmental positioning limitations with and without underlying CNS pathology). We outline directions for research on incidence and prevalence, developmental outcomes, sex differences, determinants of treatment participation, and craniofacial appearance. Despite the paucity of existing research, preliminary findings suggest that children with this condition should be screened and monitored for developmental delays or deficits, as we await more conclusive information from future studies.