Subjective evaluation of facial asymmetry with three-dimensional simulated images among the orthodontists and laypersons: a cross-sectional study

OBJECTIVES

We used three-dimensional (3D) virtual images to undertake a subjective evaluation of how different factors affect the perception of facial asymmetry among orthodontists and laypersons with the aim of providing a quantitative reference for clinics.

MATERIALS AND METHODS

A 3D virtual symmetrical facial image was acquired using FaceGen Modeller software. The left chin, mandible, lip and cheek of the virtual face were simulated in the horizontal (interior/exterior), vertical (up/down), or sagittal (forward or backward) direction in 3, 5, and 7 mm respectively with Maya software to increase asymmetry for the further subjective evaluation. A pilot study was performed among ten volunteers and 30 subjects of each group were expected to be included based on 80% sensitivity in this study. The sample size was increased by 60% to exclude incomplete and unqualified questionnaires. Eventually, a total of 48 orthodontists and 40 laypersons evaluated these images with a 10-point visual analog scale (VAS). The images were presented in random order. Each image would stop for 30 s for observers with a two-second interval between images. Asymmetry ratings and recognition accuracy for asymmetric virtual faces were analyzed to explore how different factors affect the subjective evaluation of facial asymmetry. Multivariate linear regression and multivariate logistic regression models were used for statistical data analysis.

RESULTS

Orthodontists were found to be more critical of asymmetry than laypersons. Our results showed that observers progressively decreased ratings by 1.219 on the VAS scale and increased recognition rates by 2.301-fold as the degree of asymmetry increased by 2 mm; asymmetry in the sagittal direction was the least noticeable compared with the horizontal and vertical directions; and chin asymmetry turned out to be the most sensitive part among the four parts we simulated. Mandible asymmetry was easily confused with cheek asymmetry in the horizontal direction.

CONCLUSIONS

The degree, types and parts of asymmetry can affect ratings for facial deformity as well as the accuracy rate of identifying the asymmetrical part. Although orthodontists have higher accuracy in diagnosing asymmetrical faces than laypersons, they fail to correctly distinguish some specific asymmetrical areas.

Real-time continuous image guidance for endoscopic retrograde cholangiopancreatography based on 3D/2D registration and respiratory compensation

BACKGROUND

It has been confirmed that three-dimensional (3D) imaging allows easier identification of bile duct anatomy and intraoperative guidance of endoscopic retrograde cholangiopancreatography (ERCP), which reduces the radiation dose and procedure time with improved safety. However, current 3D biliary imaging does not have good real-time fusion with intraoperative imaging, a process meant to overcome the influence of intraoperative respiratory motion and guide navigation. The present study explored the feasibility of real-time continuous image-guided ERCP.

AIM

To explore the feasibility of real-time continuous image-guided ERCP.

METHODS

We selected 2 3D-printed abdominal biliary tract models with different structures to simulate different patients. The ERCP environment was simulated for the biliary phantom experiment to create a navigation system, which was further tested in patients. In addition, based on the estimation of the patient's respiratory motion, preoperative 3D biliary imaging from computed tomography of 18 patients with cholelithiasis was registered and fused in real-time with 2D fluoroscopic sequence generated by the C-arm unit during ERCP.

RESULTS

Continuous image-guided ERCP was applied in the biliary phantom with a registration error of 0.46 mm ± 0.13 mm and a tracking error of 0.64 mm ± 0.24 mm. After estimating the respiratory motion, 3D/2D registration accurately transformed preoperative 3D biliary images to each image in the X-ray image sequence in real-time in 18 patients, with an average fusion rate of 88%.

CONCLUSION

Continuous image-guided ERCP may be an effective approach to assist the operator and reduce the use of X-ray and contrast agents.

3D-Reconstructed Contact Surface Area and Tumour Volume on Magnetic Resonance Imaging Improve the Prediction of Extraprostatic Extension of Prostate Cancer

This study is to determine whether the volume and contact surface area (CSA) of a tumour with an adjacent prostate capsule on MRI in a three-dimensional (3D) model that can predict side-specific extraprostatic extension (EPE) at radical prostatectomy (RP). Patients with localised prostate cancer (PCa) who underwent robot-assisted RP between July 2015 and March 2021 were included in this retrospective study. MRI-based 3D prostate models incorporating the PCa volume and location were reconstructed. The tumour volume and surface variables were extracted. For the prostate-to-tumour and tumour-to-prostate CSAs, the areas in which the distances were ≤ 1, ≤ 2, ≤ 3, ≤ 4, and ≤ 5 mm were defined, and their surface (cm2) were determined. Differences in prostate sides with and without pathological EPE were analysed. Multivariable logistic regression analysis to find independent predictors of EPE. Overall, 75/302 (25%) prostate sides showed pathological EPE. Prostate sides with EPE had higher cT-stage, higher PSA density, higher percentage of positive biopsy cores, higher biopsy Gleason scores, higher radiological tumour stage, larger tumour volumes, larger prostate CSA, and larger tumour CSA (all p < 0.001). Multivariable logistic regression analysis showed that the radiological tumour stage (p = 0.001), tumour volume (p < 0.001), prostate CSA (p < 0.001), and tumour CSA (p ≤ 0.001) were independent predictors of pathological EPE. A 3D reconstruction of tumour locations in the prostate improves prediction of extraprostatic extension. Tumours with a higher 3D-reconstructed volume, a higher surface area of tumour in contact with the prostate capsule, and higher surface area of prostate capsule in contact with the tumour are at increased risk of side-specific extraprostatic extension.

Development and clinical applicability of MRI-based 3D prostate models in the planning of nerve-sparing robot-assisted radical prostatectomy

The interpretation of conventional MRI may be limited by the two-dimensional presentation of the images. To develop patient-specific MRI prostate-based virtual and three-dimensional (3D)-printed models. To assess the association between 3D imaging and the pathological outcome of RARP specimen. To assess the clinical applicability of 3D models to guide nerve-sparing robot-assisted radical prostatectomy (RARP). We created virtual 3D and 3D-printed 3D models of 20 prostate cancer patients retrospectively. A comparison was made between conventional MRI and 3D-reconstructed images. The concordance between tumour lesion location in 3D models and pathology reporting of RARP specimens was assessed. Seven urologists assessed the side-specific extent of nerve-sparing based on (1) conventional MR images, (2) virtual 3D models, and (3) 3D-printed models. Clinically relevant changes in nerve-sparing and the absolute agreement between observers was analyzed using the Chi-square test and intra-class correlation coefficient (ICC). The index lesion was correctly visualized in 19/20 (95%) 3D models and the expected location of extraprostatic extension was correctly visualized in all 3D models. Clinically relevant changes in the planned extent of nerve-sparing between MRI and virtual 3D models and MRI and 3D-printed models were found in 25% and 26%. The ICC of the planned extent of nerve-sparing between urologists was 0.40 (95% CI 0.28-0.55) for conventional MRI, 0.52 (95% CI 0.39-0.66) for virtual 3D models and 0.58 (95% CI 0.45-0.71) for 3D-printed models. 3D models of the MRI prostate to guide RARP could aid urologists in the planning of nerve-sparing surgery as shown by a higher inter-observer agreement.

Multidetector computed tomography three-dimensional and multiplanar reconstruction diagnosis of a rare cause of gastrointestinal bleeding: A case report

BACKGROUND

Anastomosis of the testicular vein with the superior mesenteric vein rarely causes severe gastrointestinal bleeding. To date, there have been few studies describing its appearance on medical imaging. Here, we present multidetector computed tomography three-dimensional and multiplanar reconstruction (MPR) images of a typical digital subtraction angiography showing proven ectopic bleeding and provide the first review of the image performance.

CASE SUMMARY

A 68-year-old man who had been rushed to the hospital with a four-day history of melena and fainting underwent multiple esophagogastroduodenoscopy procedures that failed to identify the source of bleeding. We used MPR combined with three-dimensional reconstruction images, and found that the testicular vein had anastomosed with the superior mesenteric vein, and they clustered together in the jejunal vessel wall, which caused severe gastrointestinal bleeding. Digital subtraction angiography confirmed the location of bleeding. After transfusion and embolization therapy, the patient’s condition improved.

CONCLUSION

Computed tomography-MPR combined with three-dimensional images offers significant value in the localization and qualitative assessment of rare gastrointestinal hemorrhage. The features of multiphase spiral scanning can improve the accuracy of the diagnosis.

[Evaluation of the reproducibility of non-verbal facial expressions in normal persons using dynamic stereophotogrammetric system]

OBJECTIVE

To assess the reproducibility of non-verbal facial expressions (smile lips closed, smile lips open, lip purse, cheek puff) in normal persons using dynamic three-dimensional (3D) imaging and provide reference data for future research.

METHODS

In this study, 15 adults (7 males and 8 females) without facial asymmetry and facial nerve dysfunction were recruited. Each participant was seated upright in front of the 3D imaging system in natural head position. The whole face could be captured in all six cameras. The dynamic 3D system captured 60 3D images per second. Four facial expressions were included: smile lips closed, smile lips open, lip purse, and cheek puff. Before starting, we instructed the subjects to make facial expressions to develop muscle memory. During recording, each facial expression took about 3 to 4 seconds. At least 1 week later, the procedure was repeated. The rest position (T0) was considered as the base frame. The first quartile of expressions (T1), just after reaching the maximum state of expressions (T2), just before the end of maximum state of expressions (T3), the third quartile of expressions (T4), and the end of motion (T5) were selected as key frames. Using the stable part of face such as forehead, each key frame (T1-T5) of the different expressions was aligned on the corresponding frame at rest (T0). The root mean square (RMS) between each key frame and its corresponding frame at rest were calculated. The Wilcoxon signed ranks test was applied to assess statistical differences between the corresponding frames of the different facial expressions.

RESULTS

Facial expressions like smile lips closed, smile lips open, and cheek puff were reproducible. Lip purse was not reproducible. The statistically significant differences were found on the T2 frame of the repeated lip purse movement.

CONCLUSION

The dynamic 3D imaging can be used to evaluate the reproducibility of facial expressions. Compared with the qualitative analysis and two-dimensions analysis, dynamic 3D images can be able to more truly represent the facial expressions which make the research more reliable.

Intentional Replantation to Treat Apical Periodontitis of Maxillary First Molar with Foreign Body Located Outside Apical Foramen Using CBCT: A Case Report

The recent use of cone beam computed tomography (CBCT) in the field of dentistry to obtain 3-dimensional (3D) images has enabled more effective examination and diagnosis in endodontic treatment. Such information has also been reported to be of benefit in surgical endodontic treatment such as intentional replantation. Here, we report a case of intentional replantation with the assistance of CBCT in which a good therapeutic outcome was achieved. The patient was a 30-year-old woman who visited our hospital with the chief complaint of spontaneous pain in the right maxillary first molar. Dental radiographs revealed a radiolucent area in the apical portion of the distal root, and a radiopaque area thought to be a broken shard from a small surgical instrument measuring approximately 1.5 mm in length. The shard was located outside the distal apical foramen. Based on these findings, the diagnosis was acute suppurative apical periodontitis of the right maxillary first molar. Infected root canal therapy was subsequently commenced. The patient's symptoms showed no improvement, however, and the pain persisted. Therefore, dental CBCT was performed to obtain 3D images, which confirmed a radiopaque area thought to be a broken shard from a small surgical instrument located outside the apical foramen of the distal root and facing in a direction that made it impossible to remove from the root canal. Because the patient's symptoms had shown no improvement and a foreign body was observed outside the apical foramen, intentional replantation combined with root resection was performed with informed consent. At a 1-year follow-up visit, progress was good, and there were no reported symptoms or signs. When reaching a diagnosis is difficult based on clinical findings and dental radiographs alone, the 3D images provided by CBCT offer a means of securing a more reliable diagnosis, allowing planning of treatment to be more effective.

An extremely rare case with right superior pulmonary vein translocation

Background

There have been a number of reports on pulmonary venous anomalies. However, most of the reports focused on the anatomical branching pattern of the peripheral pulmonary veins.

Case presentation

We report a 75-year-old female whose right superior pulmonary vein V1 existed dorsal to the right main pulmonary artery and V2+3 existed dorsal to V4+5. Thus, we could not find V1 and V2+3 in the hilum just after a thoracotomy to perform right upper lobectomy for lung cancer. Thus, the right main pulmonary artery and the superior trunk (A1+3) were exposed without cutting the superior pulmonary vein.

Conclusion

There has been no report so far regarding this type of pulmonary vein translocation. Preoperative three-dimensional computed tomography images were helpful to identify this variant.

Characteristic features of the insertions of the distal tibiofibular ligaments on three-dimensional computed tomography- cadaveric study

Purpose

The purpose of this study was to clarify the insertion sites of the anterior inferior tibiofibular ligament (AITFL) and posterior inferior tibiofibular ligament (PITFL) and related osseous landmarks on three-dimensional computed tomography images.

Methods

Twenty-nine non-paired, formalin-fixed human cadaveric ankles were evaluated. The tibial and fibular insertion sites of the AITFL and PITFL were identified. The morphology and location of the insertion sites and their positional relationships with osseous structures were analyzed on three-dimensional computed tomography images.

Results

The AITFL had a trapezoidal shape, with fibers that ran obliquely lateral from a wider insertion at the lateral distal tibia to the medial distal fibula. The PITFL had a similar shape to the AITFL; however, it ran more horizontally, with fibers running in the same direction. In the tibia, the anterior capsular ridge and the Chaput’s and Volkmann’s tubercles were useful osseous landmarks for the insertion sites. In the fibula, the centers of the insertion sites of the AITFL and PITFL were located on the edges of the distal anterior and posterior fibula, which were useful osseous landmarks. The mean distances between the center points of the tibial and fibular insertion sites of the AITFL and PITFL were 10.1 ± 2.4 mm and 11.7 ± 2.6 mm, respectively.

Conclusions

The relationships between the characteristic features of the distal tibia and fibula and the insertions of the AITFL and PITFL were consistent. The present findings improve the understanding of the anatomy of the insertions of the distal tibiofibular syndesmotic joint.

Muscle fibre morphology and microarchitecture in cerebral palsy patients obtained by 3D synchrotron X-ray computed tomography

BACKGROUND

Synchrotron X-ray computed tomography (SXCT) allows for three-dimensional imaging of objects at a very high resolution and in large field-of-view.

PURPOSE

The aim of this study was to use SXCT imaging for morphological analysis of muscle tissue, in order to investigate whether the analysis reveals complementary information to two-dimensional microscopy.

METHODS

Three-dimensional SXCT images of muscle biopsies were taken from participants with cerebral palsy and from healthy controls. We designed morphological measures from the two-dimensional slices and three-dimensional volumes of the images and measured the muscle fibre organization, which we term orientation consistency.

RESULTS

The muscle fibre cross-sectional areas were significantly larger in healthy participants than in participants with cerebral palsy when carrying out the analysis in three dimensions. However, a similar analysis carried out in two dimensions revealed no patient group difference. The present study also showed that three-dimensional orientation consistency was significantly larger for healthy participants than for participants with cerebral palsy.

CONCLUSION

Individuals with CP have smaller muscle fibres than healthy control individuals. We argue that morphometric measures of muscle fibres in two dimensions are generally trustworthy only if the fibres extend perpendicularly to the slice plane, and otherwise three-dimensional aspects should be considered. In addition, the muscle tissue of individuals with CP showed a decreased level of orientation consistency when compared to healthy control tissue. We suggest that the observed disorganization of the tissue may be induced by atrophy caused by physical inactivity and insufficient neural activation.

Does vaginal delivery cause more damage to the pelvic floor than cesarean section as determined by 3D ultrasound evaluation? A systematic review

INTRODUCTION AND HYPOTHESIS

Pregnancy and delivery are well-established risk factors for pelvic floor dysfunction (PFD), but the physiopathology, such as the delivery route, is not well understood. This study evaluated the impact of delivery route on the pelvic floor muscles via 3D ultrasound.

METHODS

This review is registered in the PROSPERO database. The criteria for inclusion were prospective studies with 3D translabial ultrasound assessment in primigravida women during pregnancy and postpartum published in English, Spanish or Portuguese between 1980 and 2016. We excluded studies that did not include the topic of urogenital hiatus measurement and literature reviews. The MeSH terms were obstetric delivery, postpartum period, labor, parturition, three-dimensional images, ultrasonography, pelvic floor, and pelvic floor disorders.

RESULTS

The search retrieved 155 articles. After analysis, 6 articles were included. Four studies showed that vaginal delivery (VD) was associated with a larger hiatal area. One study associated the hiatal area with levator ani muscle (LAM) defects in VD. Four articles evaluated the bladder neck, 3 of which showed a significant increase in bladder neck mobility associated with VD and 1 showed decreased bladder neck elevation, not associated with the delivery mode; the first 3 articles all evaluated LAM injuries and showed an association between VD and LAM injury. Women who underwent VD presented defects of the puborectalis muscle.

CONCLUSIONS

Vaginal delivery was associated with a higher number of LAM injuries, puborectalis defects, increased bladder neck mobility, and enlargement of the hiatal area.

Feasibility Study of the Three-Dimensional Flexible Endoscope in Endoscopic Submucosal Dissection: An ex vivo Animal Study

BACKGROUND/AIM

Clinical application of 3-dimensional (3D) technology for flexible endoscopes has not been reported. We developed a 3D flexible endoscope and conducted a feasibility study of endoscopic submucosal dissection (ESD) in porcine stomach.

METHODS

Four endoscopists used a 3D flexible endoscope to perform a total of 8 ESD procedures on resected porcine stomachs. We assessed the en bloc resection rate, perforation rate, and mechanical issues that arise during ESD. A visual analog scale (0, 2D superior; 100, 3D superior) was used to evaluate the depth perception, sense of security of the procedure, and eyestrain of 3D visualization.

RESULTS

En bloc resection was achieved in all cases and there were no cases of perforation or mechanical issues. Depth perception and sense of security were rated 85.5 ± 12.4 and 70.7 ± 9.7 respectively (mean ± SDs). Eyestrain was rated high for 3D visualization (mean ± SDs, 12.6 ± 8.6).

CONCLUSIONS

ESD using a 3D flexible endoscope was technically feasible. The endoscopists reported good depth perception and a high sense of security when using 3D visualization but also noted strong eyestrain.

Evaluation of cephalometric landmark identification on CBCT multiplanar and 3D reconstructions

OBJECTIVE

To evaluate the reliability of three-dimensional (3D) landmark identification in cone-beam computed tomography (CBCT) using two different visualization techniques.

MATERIALS AND METHODS

Twelve CBCT images were randomly selected. Three observers independently repeated three times the identification of 30 landmarks using 3D reconstructions and 28 landmarks using multiplanar views. The values of the coordinates X, Y, and Z of each point were obtained and the intraclass correlation coefficient (ICC) was calculated.

RESULTS

The ICC of the 3D visualization was rated >0.90 in 67.76% and 45.56%, and ≤0.45 in 13.33% and 14.46% of the intraobserver and interobserver assessments, respectively. The ICC of the multiplanar visualization was rated >0.90 in 82.16% and 78.56% and ≤0.45 in only 16.7% and 8.33% of the intraobserver and interobserver assessments, respectively. An individual landmark classification was done according to ICC values.

CONCLUSIONS

The frequency of highly reliable values was greater for multiplanar than 3D reconstructions. Overall, lower reliability was found for points on the condyle and higher reliability for those on the midsagittal plane. Depending on the anatomic region, the observer must choose the most reliable type of image visualization.

The perception of facial asymmetry using 3-dimensional simulated images

OBJECTIVE

To investigate the perception of facial asymmetry in young adults to identify the amounts of chin asymmetry that can be regarded as normal and may benefit from correction.

MATERIALS AND METHODS

Three-dimensional (3D) images of 56 individuals of mixed ethnicity were obtained and used to produce average 3D images of male and female faces. Distortion was then applied to these average faces using a 3D graphics package to simulate different amounts of chin point asymmetry. Five observer groups (lay individuals, dental students, dental care professionals, dental practitioners, and orthodontists) assessed timed presentations of 3D images, rating them as "normal," "acceptable," or "would benefit from correction." Time-to-event analysis was used to assess the level of chin asymmetry perceived as normal and beneficial for correction for each group.

RESULTS

The factors influencing the perception of facial asymmetry were the degree of asymmetry and the observer group. Direction of the asymmetry and gender of the assessed individual did not affect the perception of asymmetry, except in the 4- to 6-mm distortion range. The gender of the observer had no influence on perception. There were statistically significant differences in the amounts of asymmetry that the laypeople and orthodontists considered to be normal (5.6 ± 2.7 mm and 3.6 ± 1.5 mm, respectively; P < .001) and felt would benefit from surgical correction (11.8 ± 4.0 mm and 9.7 ± 3.0 mm, respectively; P  =  .001).

CONCLUSIONS

Perception of asymmetry is affected by the amount of asymmetry and the observer group, with orthodontists being more critical.