Using Deep Learning and B-Splines to Model Blood Vessel Lumen from 3D Images.

Accurate geometric modeling of blood vessel lumen from 3D images is crucial for vessel quantification as part of the diagnosis, treatment, and monitoring of vascular diseases. Our method, unlike other approaches which assume a circular or elliptical vessel cross-section, employs parametric B-splines combined with image formation system equations to accurately localize the highly curved lumen boundaries. This approach avoids the need for image segmentation, which may reduce the localization accuracy due to spatial discretization. We demonstrate that the model parameters can be reliably identified by a feedforward neural network which, driven by the cross-section images, predicts the parameter values many times faster than a reference least-squares (LS) model fitting algorithm. We present and discuss two example applications, modeling the lower extremities of artery-vein complexes visualized in steady-state contrast-enhanced magnetic resonance images (MRI) and the coronary arteries pictured in computed tomography angiograms (CTA). Beyond applications in medical diagnosis, blood-flow simulation and vessel-phantom design, the method can serve as a tool for automated annotation of image datasets to train machine-learning algorithms.

Accuracy of intraoral scan with prefabricated aids and stereophotogrammetry compared with open tray impressions for complete-arch implant-supported prosthesis: A clinical study.

OBJECTIVES: The aim of this clinical study was to compare the accuracy of intraoral scan system (IOS) with prefabricated aids and stereophotogrammetry (SPG) compared with open tray implant impression (OI) for complete-arch implant-supported fixed dental prostheses (CIFDP). MATERIALS AND METHODS: Patients needing CIFDP were enrolled in this study. OI, reference standard, IOS with prefabricated aids, and SPG were performed for each patient. Distance and angle deviations between all pairs of abutment analogs, root mean square (RMS) errors between the aligned test and reference model, and chairside time were measured. The effect of inter-abutment distance, jaw (maxilla or mandible), number of implants, and arch length on deviations was analyzed. The mixed effect model was applied to analyze deviations and RMS errors. RESULTS: Fifteen consecutive individuals (6 females and 9 males, 47-77 years old) with 22 arches (9 upper and 13 lower jaws) and 115 implants were included. There was no significant difference in distance deviation comparing SPG and IOS with OI (p > .05). IOS showed a significantly greater angle deviation and RMS errors than SPG (median 0.40° vs. 0.31°, 69 µm vs. 45 µm, p < .01). The inter-abutment distance was negatively correlated with the accuracy of SPG and IOS (p < .05). The chairside time for IOS, SPG, and OI was 10.49 ± 3.50, 14.71 ± 2.86, and 20.20 ± 3.01 min, respectively (p < .01). CONCLUSIONS: The accuracy of SPG and IOS with prefabricated aids was comparable. IOS was the most efficient workflow.

Making the Most of Single Sensor Information: A Novel Fusion Approach for 3D Face Recognition Using Region Covariance Descriptors and Gaussian Mixture Models.

Most commercially successful face recognition systems combine information from multiple sensors (2D and 3D, visible light and infrared, etc.) to achieve reliable recognition in various environments. When only a single sensor is available, the robustness as well as efficacy of the recognition process suffer. In this paper, we focus on face recognition using images captured by a single 3D sensor and propose a method based on the use of region covariance matrixes and Gaussian mixture models (GMMs). All steps of the proposed framework are automated, and no metadata, such as pre-annotated eye, nose, or mouth positions is required, while only a very simple clustering-based face detection is performed. The framework computes a set of region covariance descriptors from local regions of different face image representations and then uses the unscented transform to derive low-dimensional feature vectors, which are finally modeled by GMMs. In the last step, a support vector machine classification scheme is used to make a decision about the identity of the input 3D facial image. The proposed framework has several desirable characteristics, such as an inherent mechanism for data fusion/integration (through the region covariance matrixes), the ability to explore facial images at different levels of locality, and the ability to integrate a domain-specific prior knowledge into the modeling procedure. Several normalization techniques are incorporated into the proposed framework to further improve performance. Extensive experiments are performed on three prominent databases (FRGC v2, CASIA, and UMB-DB) yielding competitive results.

Three-dimensional multi-gene expression maps reveal cell fate changes associated with laterality reversal of zebrafish habenula.

The conserved bilateral habenular nuclei (HA) in vertebrate diencephalon develop into compartmentalized structures containing neurons derived from different cell lineages. Despite extensive studies demonstrated that zebrafish larval HA display distinct left-right (L-R) asymmetry in gene expression and connectivity, the spatial gene expression domains were mainly obtained from two-dimensional (2D) snapshots of colorimetric RNA in situ hybridization staining which could not properly reflect different HA neuronal lineages constructed in three-dimension (3D). Combing the tyramide-based fluorescent mRNA in situ hybridization, confocal microscopy and customized imaging processing procedures, we have created spatial distribution maps of four genes for 4-day-old zebrafish and in sibling fish whose L-R asymmetry was spontaneously reversed. 3D volumetric analyses showed that ratios of cpd2, lov, ron, and nrp1a expression in L-R reversed HA were reversed according to the parapineal positions. However, the quantitative changes of gene expression in reversed larval brains do not mirror the gene expression level in the obverse larval brains. There were a total 87.78% increase in lov+ nrp1a+ and a total 12.45% decrease in lov+ ron+ double-positive neurons when the L-R asymmetry of HA was reversed. Thus, our volumetric analyses of the 3D maps indicate that changes of HA neuronal cell fates are associated with the reversal of HA laterality. These changes likely account for the behavior changes associated with HA laterality alterations.

Assessment of pedicle size in patients with scoliosis using EOS 2D imaging: a validity and reliability study.

PURPOSE: Free-hand pedicle screw insertion methods are widely used for screw insertion during scoliosis surgery. Preoperative knowledge about the pedicle size helps to maximize screw containment and minimize the risk of pedicle breach. Radiographs taken by a biplanar low-dose X-ray device (EOS) have no divergence in the vertical plane. The criterion validity and reliability of preoperative EOS images for pedicle size measurements in patients with idiopathic scoliosis (IS) was investigated in this study. METHODS: Sixteen patients who underwent surgical treatment for IS were prospectively included. Intra- and extracortical pedicle height and width measurements on EOS images were compared with reconstructed intra-operative 3D images of the isthmus of included pedicles. Secondly, intra- and interobserver reliability of pedicle size measurements on EOS images was determined. RESULTS: The total number of analyzed pedicles was 203. The correlation between the EOS and 3D scan measurements was very strong for the intra- and extracortical pedicle height and strong for the intra- and extracortical pedicle width. There are, however, significant, but likely clinically irrelevant differences (mean absolute differences < 0.43 mm) between the two measure methods for all four measurements except for extracortical pedicle height. For pedicles classified as Nash-Moe 0, no significant differences in intra- and extracortical pedicle width were observed. Both intra- and interobserver reliability was excellent for all pedicle size measurements on EOS images. CONCLUSION: The results of this study indicate a good validity and reliability for pedicle size measurements on EOS radiographs. Therefore, EOS radiographs may be used for a preoperative estimation of pedicle size and subsequent screw diameter in patients with IS.

Body measurement of riding horses with a versatile tablet-type 3D scanning device.

The measurement of various body dimensions of horses plays a significant role in quality improvement, genetic breeding, health, and soundness. There has been significant advancement in the technology for acquiring stereoscopic images with a three-dimensional (3D) scanner. This study aimed to validate the accuracy of body measurements obtained from stereoscopic images taken with a 3D scanner. We manually took the following body measurements for 8 riding horses: height at the withers, height at the back, height at the croup, chest depth, width of the chest, width of the croup, width of the waist, girth circumference, cannon circumference, and body length. Using a versatile tablet-type 3D scanning device, we captured a 3D image of each horse. Relative errors varied from -1.37% to 6.25%. The correlation coefficient between manual and 3D measurements was significant for all body measurements (P<0.01) except for width of the waist and cannon circumference. The low accuracy of cannon circumference (r=0.248) was due to effect of hair. A simple regression analysis of all body measurements revealed a strong correlation (P<0.001, R2=0.9994, root-mean-square error [RMSE]=1.522). Notable advantages of this methodology include high accuracy, good operability, non-contact, high versatility, and low cost. Further studies are required for the establishment of an accurate measurement methodology that can scan the whole body in a shorter time.

Utilization of a new technology of 3D biliary CT for ERCP-related procedures: a case report.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is still performed using two-dimensional (2D) X-ray images. The success rate and risk of complications are considered operator-dependent. We explored performing an ERCP-related procedure with 3D-computed tomography (CT) biliary imaging for preoperative simulation and intraoperative reference in a patient with malignant biliary obstruction. CASE PRESENTATION: The patient was a 66-year-old man who underwent rectal resection and postoperative chemotherapy for rectal cancer. A liver metastasis caused obstructive jaundice and acute cholangitis, necessitating emergency hospitalization. A 3.5 cm mass in the hilar region of the biliary tree caused type IV biliary obstruction according to the Bismuth-Corlette classification of hilar cholangiocarcinoma. ERCP and biliary drainage were performed repeatedly, but had no effect. Given that selective bile duct drainage had proven extremely difficult with the conventional procedures, three-dimensional (3D) images were created from preoperative CT image data using a 3D image reconstruction system (SYNAPSE VINCENT version 5, FUJIFILM Corporation, Tokyo, Japan). Using the 3D images for preoperative planning and intraoperative reference, biliary drainage and stent placement were successfully performed without complications. Postoperatively, the patient had no further cholangitis or need for stent replacement up to his death. CONCLUSIONS: We report the first case of an ERCP-related procedure with 3D biliary imaging for preoperative simulation and intraoperative reference in a patient with malignant biliary obstruction. The 3D image reconstruction is useful for preoperative planning and could contribute to an increased success rate, decreased complications, a shorter operation time, and reduced radiation exposure to the operator.

Three-Dimensional Visualisation of Skeletal Cavities.

Bones contain spaces within them. The extraction and the analysis of those cavities are crucial in the study of bone tissue function and can inform about pathologies or past traumatic events. The use of medical imaging techniques allows a non-invasive visualisation of skeletal cavities opening a new frontier in medical inspection and diagnosis. Here, we report the application of a new mesh-based approach for the isolation of skeletal cavities of different size and geometrical structure. We apply a mesh-based approach to extract (i) the main virtual cavities inside the human skull, (ii) a complete human endocast, (iii) the inner vasculature of the malleus bone and (iv) the medullary of a human femur. The detailed description of the mesh-based isolation method and its pioneristic application to four different case-studies show the potential of this approach in medical visualisation.

Longitudinal 3D Assessment of Facial Asymmetry in Unilateral Cleft Lip and Palate.

OBJECTIVE: Longitudinal evaluation of asymmetry of the surgically managed unilateral cleft lip and palate (UCLP) to assess the impact of facial growth on facial appearance. DESIGN: Prospective study. SETTING: Glasgow Dental Hospital and School, University of Glasgow, United Kingdom. PATIENTS: Fifteen UCLP infants. METHOD: The 3-D facial images were captured before surgery, 4 months after surgery, and at 4-year follow-up using stereophotogrammetry. A generic mesh which is a mathematical facial mask that consists of thousands of points (vertices) was conformed on the generated 3-D images. Using Procustean analysis, an average facial mesh was obtained for each age-group. A mirror image of each average mesh was mathematically obtained for the analysis of facial dysmorphology. Facial asymmetry was assessed by measuring the distances between the corresponding vertices of the original and the mirror copy of the conformed meshes, and this was displayed in color-coded map. RESULTS: There was a clear improvement in the facial asymmetry following the primary repair of cleft lip. Residual asymmetry was detected around the nasolabial region. The nasolabial region was the most asymmetrical region of the face; the philtrum, columella, and the vermillion border of the upper lip showed the maximum asymmetry which was more than 5 mm. Facial growth accentuated the underlying facial asymmetry in 3 directions; the philtrum of the upper lip was deviated toward the scar tissue on the cleft side. The asymmetry of the nose was significantly worse at 4-year follow-up ( P < .05). CONCLUSION: The residual asymmetry following the surgical repair of UCLP was more pronounced at 4 years following surgery. The conformed facial mesh provided a reliable and innovative tool for the comprehensive analysis of facial morphology in UCLP. The study highlights the need of refining the primary repair of the cleft and the potential necessity for further corrective surgery.

Are there vocal cues to human developmental stability? Relationships between facial fluctuating asymmetry and voice attractiveness.

Fluctuating asymmetry (FA), deviation from perfect bilateral symmetry, is thought to reflect an organism's relative inability to maintain stable morphological development in the face of environmental and genetic stressors. Previous research has documented negative relationships between FA and attractiveness judgments in humans, but scant research has explored relationships between the human voice and this putative marker of genetic quality in either sex. Only one study (and in women only) has explored relationships between vocal attractiveness and asymmetry of the face, a feature-rich trait space central in prior work on human genetic quality and mate choice. We therefore examined this relationship in three studies comprising 231 men and 240 women from two Western samples as well as Hadza hunter-gatherers of Tanzania. Voice recordings were collected and rated for attractiveness, and FA was computed from two-dimensional facial images as well as, for a subset of men, three-dimensional facial scans. Through meta-analysis of our results and those of prior studies, we found a negative association between FA and vocal attractiveness that was highly robust and statistically significant whether we included effect sizes from previously published work, or only those from the present research, and regardless of the inclusion of any individual sample or method of assessing FA (e.g., facial or limb FA). Weighted mean correlations between FA and vocal attractiveness across studies were -.23 for men and -.29 for women. This research thus offers strong support for the hypothesis that voices provide cues to genetic quality in humans.

Effect of Leg-to-Body Ratio on Body Shape Attractiveness.

Recent studies have examined various aspects of human physical attractiveness. Attractiveness is considered an evolved psychological mechanism acquired via natural selection because an attractive body reflects an individual's health and fertility. The length of the legs is an often-emphasized aspect of attractiveness and has been investigated using the leg-to-body ratio (LBR), which reflects nutritional status of the infant, health status, fecundity, and other factors that are predictive of physical fitness. However, previous studies of leg length and physical fitness have produced mixed results. The present study investigated the relationship between LBR, defined as the height to perineum divided by total height, and perceived attractiveness. Three-dimensional stimuli (11 male and 11 female) were constructed with various LBR features. Each stimulus was rated by 40 women and 40 men in Japan on a 7-point scale. The results showed that the values closest to the average LBRs were rated as the most attractive. Furthermore, by fitting a quadratic curve on the relationship between attractiveness and LBR, an inverted U-shaped curve with the peak located at the average LBR was observed. In addition, high LBR values were rated as more attractive in females, whereas the opposite was true for males. These results suggest that average LBR is indicative of good health and good reproductive potential, whereas more extreme values are avoided because they could be indicative of diseases and other maladaptive conditions.

A study of the effect of visual depth information on upper limb movement by use of measurement of smoothness.

[Purpose] This study verified that the smoothness of reaching movements is able to quantitatively evaluate the effects of two- and three-dimensional images on movement in healthy people. In addition, clinical data of cerebrovascular accident patients were also analyzed by the same method. [Subjects] Ten healthy adult volunteers and two male patients with previous cerebrovascular accidents participated. [Methods] The subjects were tasked with reaching for objects shown on a display. The target and virtual limb, rendered with computer graphics, were shown on the display. Movements of the virtual limb were synchronized with those of the subject. Healthy subjects reached for targets with their dominant arm, and cerebrovascular accident patients used their paretic arm. A polarized display and polarized glasses were used when the subjects were shown three-dimensional images. In the present study, jerk cost was used to quantify the smoothness of movement. [Results] Six of the 10 healthy subjects had significantly smoother reaching movements when viewing the three-dimensional images. The two cerebrovascular accident patients tended to have smoother movements in response to the three-dimensional images. [Conclusion] Analysis of the smoothness of movement was able to detect the influence of the depth cue in vision on movement quantitatively for the healthy subjects and cerebrovascular accident patients.

Teaching Pterygopalatine Fossa Anatomy Using 3D Images and Physical Model: A Novel Teaching Strategy.

Medical students often struggle to appreciate the anatomy of the pterygopalatine fossa. This is due to the difficulty in understanding the spatial orientation through textbook diagrams, as well as its deeper location and smaller size in cadaveric specimens. Research has proven that three-dimensional visualization enhances the spatial understanding of anatomy. However, studies have not compared the effectiveness of two different instructional designs that cater to 3D visualization. We conducted a mixed methodology (quasi-experimental pre-test/post-test control design with additional qualitative components) study to compare the effectiveness of a physical model and a 3D image in small-group teaching. The students were divided into control and intervention groups based on their roll numbers. The control group utilized a series of 3D images delivered through Microsoft PowerPoint software on computers. The students in the intervention group used a physical model made of cardboard, with colored wires representing the neurovascular structures. We used 20 spatial anatomy-based multiple-choice questions (MCQs) to assess knowledge acquisition before and after the small group discussion. Additionally, we utilized a validated 10-item feedback questionnaire to evaluate participants' perception of the teaching sessions. There was no significant difference in the knowledge gain and perception scores between the control and intervention groups. These findings suggest that a well-designed 3D image can provide an equivalent learning outcome and level of satisfaction compared to a physical model. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-024-02063-3.

One-shot technology for three-dimensional imaging of large animals: perspectives for ruminant management.

In numerous systems of animal production, there is increasing interest in the use of three-dimensional (3D)-imaging technology on farms for its ability to easily and safely measure traits of interest in living animals. With this information, it is possible to evaluate multiple morphological indicators of interest, either directly or indirectly, and follow them through time. Several tools for this purpose were developed, but one of their main weaknesses was their sensitivity to light and animal movement, which limited their potential for large-scale application on farms. To address this, a new device, called Deffilait3D and based on depth camera technology, was developed. In tests on 31 Holstein dairy cows and 13 Holstein heifers, the values generated for most measured indicators were highly repeatable and reproducible, with coefficients of variation lower than 4%. A comparison of measurements obtained from both Deffilait3D and the previous validated system, called Morpho3D, revealed a high degree of similarity for most selected traits, e.g., less than 0.2% variation for animal volume and 1.2% for chest depth, with the highest degree of difference (8%) noted for animal surface area. Previously published equations used to estimate body weight with the Morpho3D device were equally valid using Deffilait3D. This new device was able to record 3D images regardless of the movement of animals and it is affected only by direct daylight. The ongoing step is now to develop methods for automated analysis and extraction from images, which should enable the rapid development of new tools and potentially lead to the large-scale adoption of this type of device on commercial farms.

Preoperative Simulation of Intraoperative Findings in Surgical Clipping of Posterior Communicating Artery Aneurysms Using T2-Weighted 3D Images.

BACKGROUND: Tentorium resection and detachment from the oculomotor nerve are sometimes required for surgical clipping of unruptured posterior communicating artery (PCoA) aneurysms. Using T2-weighted 3D images, we aimed to identify the preoperative radiological features required to determine the necessity of these additional procedures. METHODS: We reviewed 30 patients with unruptured PCoA aneurysms who underwent surgical clipping and preoperative simulation using T2-weighted 3D images for measurement of the distance between the tentorium and aneurysm. Aneurysms were classified into superior type (superior to the tentorium) and inferior type (inferior to the tentorium). RESULTS: Seven patients (23%) underwent tentorium resection; all had the inferior type (superior vs. inferior, 0% vs. 33%, p = 0.071). In the 21 patients with the inferior type, the distance from the tentorium to the aneurysmal neck was 2.2 ± 1.1 mm and 0.0 ± 0.5 mm without and with tentorium resection (p < 0.01), respectively. An optimal cutoff value of ≤ +0.84 mm was identified for tentorium resection (area under the curve (AUC) = 0.96). Furthermore, 17 patients (57%) showed tight aneurysm attachment to the oculomotor nerve; all had the inferior type (0% vs. 81%, p < 0.01). The distance from the aneurysm tip to the tentorium was 1.1 ± 1.2 mm and -1.7 ± 1.4 mm without and with attachment (p < 0.01). The optimal cutoff value was ≤ +0.45 mm (AUC = 0.92). CONCLUSIONS: Measurement of the distance between the tentorium and aneurysmal neck or tip with T2-weighted 3D images is effective for preoperative simulation for surgical clipping of PCoA aneurysms.

Three-Dimensional Analysis of the Windlass Mechanism Using Weightbearing Computed Tomography in Healthy Volunteers.

BACKGROUND: The windlass mechanism (WM) increases the longitudinal arch of the foot via tension of the plantar aponeurosis during dorsiflexion of the metatarsophalangeal (MTP) joint. The purpose of this study was to perform a 3-dimensional evaluation of the displacement of each joint and the height of the navicular during dorsiflexion of the first MTP joint by using weightbearing computed tomography (CT). METHODS: Participants were 6 men and 8 women with 23 healthy feet. CT of the foot with a load equivalent to the participant's body weight was performed. The first MTP joint was in the neutral position and dorsiflexed 30 degrees. Between the conditions, we measured the (1) rotation of each bone, (2) rotation of the distal bone with respect to the proximal bone at each joint, and (3) height of the navicular. RESULTS: With respect to the tibia, the calcaneus was at 0.8 ± 0.7 degrees dorsiflexion and 1.4 ± 0.9 degrees inversion, while the talus was at 2.0 ± 1.2 degrees dorsiflexion and 0.1 ± 0.8 degrees eversion. The navicular was at 1.3 ± 1.2 degrees dorsiflexion and 3.2 ± 2.1 degrees inversion, whereas the medial cuneiform was at 0.3 ± 0.6 degrees plantarflexion and 1.3 ± 1.1 degrees inversion. At the talonavicular joint, the navicular was at 0.7 ± 1.3 degrees plantarflexion, whereas at the cuneonavicular joint, the medial cuneiform bone was at 1.4 ± 1.4 degrees plantarflexion. The height of the navicular increased by 1.1 ± 0.6 mm. CONCLUSION: We 3-dimensionally confirmed the dynamics of WM and found that the calcaneus, navicular, and medial cuneiform moved in all 3 planes. The results suggest that the cuneonavicular joint has the greatest movement among the joints. We believe that these findings will help to elucidate the pathogenesis of WM-related diseases and lead to advances in treatments for pathologies involving the longitudinal arch. LEVEL OF EVIDENCE: Level IV, case series.

Higher femoral anteversion restoration accuracy after total hip arthroplasty with a proximally fixed anatomic stem than with a generic straight double-tapered stem.

BACKGROUND: Femoral antetorsion in uncemented hip replacement hardly can be modified and the restoration of the anatomic anteversion might be difficult with standard stems. We compared femoral anteversion restoration of a generic straight stem with a proximally fixed anatomic stem that included a dual sagittal curvature and a proximal torsion. It was hypothesised that the restoration of the anteversion was more accurate with the anatomic stem. PATIENTS AND METHODS: In this comparative study data were collected prospectively of 80 consecutive patients with total hip arthroplasty for primary osteoarthritis. In the first 40 patients (Group I) a cementless proximally fixed anatomic stem with 15° antetorsion of the shaft and a dual sagittal curvature was used. Its design was based on a database of 3D CT images of 600 hips. For comparison a cementless generic straight double-tapered stem was implanted in the next 40 patients (Group II). All operations were performed by one experienced surgeon. All patients had a preoperative 3D planning. A low-dose CT scan was performed at 3 months postoperatively to determine the postoperative stem anteversion. RESULTS: The demographics were similar in both groups. In group I the mean postoperative femoral anteversion was similar to the preoperative one (22.1° ± 10.2° vs. 20.4° ± 9°; p = 0.2). In Group II, the mean postoperative femoral anteversion was lower (12.9° ± 10.8°, vs. 18.3° ± 12°; p = 0.02). CONCLUSIONS: Uncemented standard femoral stems tend to reduce femoral anteversion. The used anatomic stem restored femoral anteversion better. The clinical impact of this finding has to be proven.

Assessing Enamel Wear of Monolithic Ceramics With Micro-CT and Intra-oral Scanner.

OBJECTIVE: This in vitro study aimed to investigate enamel wear against 3 monolithic ceramics using 2 methods of measurement. METHODS: Three groups of standard flat monolithic ceramic specimens including zirconia-reinforced lithium silicate glass (Vita Suprinity, VITA Zahnfabrik), yttria-stabilised tetragonal zirconia (Lava Esthetic Zirconia), and lithium disilicate glass (IPS e.max Press, Ivoclar Vivadent) were prepared, with human enamel used as the control group. Each specimen was subjected to the 2-body wear test at 49 N for 250,000 cycles. Enamel antagonists were evaluated with micro-computed tomography (CT) and intra-oral scanner, allowing 3-dimensional images of vertical wear and volumetric loss of enamel antagonists to be calculated. One-way analysis of variance followed by Student-Newman-Keuls post hoc tests were used to examine the differences in vertical wear/volumetric loss amongst the groups. Paired t tests and intra-class correlations were used to compare vertical wear/volumetric loss between the micro-CT and intra-oral scanner groups. RESULTS: No significant difference in vertical wear was found amongst all groups. More volumetric loss was found in all test groups than in the control group (P < .001), but no significant difference was found amongst the test groups. There was a moderate positive correlation (r = 0.535, P = .033) between the vertical wear and volumetric loss. No significant difference between the 2 methods of measurement was found. CONCLUSIONS: Monolithic ceramics induce more enamel wear than natural teeth. Both micro-CT and intra-oral scanners can be used for measuring tooth wear with similar performance.

Right gyrus cinguli low-grade astrocytoma recurrence removed through a contralateral transfalcine approach with a 4K-3D exoscope.

BACKGROUND: Brain tumor surgery has been using operative microscope for years. Recently, thanks to developments in surgical technology with procedures performed on head-up displays, exoscopes have been introduced as an alternative to microscopic vision. CASE PRESENTATION: We present a case of a 46-year-old patient with a low-grade glioma recurrence of the right gyrus cinguli removed with a contralateral transfalcine approach using an exoscope (ORBEYE 4K-three-dimensional (3D) exoscope, Sony Olympus Medical Solutions Inc., Tokyo, Japan). The operating room setup for this approach is illustrated. During the procedure, the surgeon was seated with head and back in an upright position, while the camera was aligned with the surgical corridor. The exoscope provided detailed, high-quality 4K-3D images of the anatomical structures and optimal depth perception, making surgery accurate and precise. At the end of the resection, an intraoperative MRI scan showed complete removal of the lesion. The patient was discharged on postoperative day 4 with an excellent performance on neuropsychological examination. CONCLUSIONS: In this clinical case the contralateral approach was favorable because the glioma was located close to the midline and because it offered a straight path to the tumor, minimizing retraction on the brain. The exoscope provided the surgeon with important advantages in terms of anatomical visualization and ergonomics during the entire procedure.

Anatomists' uses of human skeletons: Ethical issues associated with the India bone trade and anonymized archival collections.

Concerns have recently been expressed about the continuing availability of human bones from India, obtained originally for educational purposes but lacking the requisite informed consent that would be expected today. More generally, a broader claim is being made, namely, that the practice of using any unconsented bones in educational settings is unethical and should cease. These calls, in turn, raise broader issues regarding the availability of anonymous archival collections in anatomy museums. Although this debate centers on undergraduate anatomy teaching, much anthropological research utilizes human remains of past populations for which there can have been no consent. A suggested alternative for undergraduate teaching is the use of 3D images of human bones, rather than the bones themselves. In addressing these issues, the background to the India bone trade is assessed, and the year 1985 is pinpointed as having significant ethical weight. The cultural and ethical interests inherent in studying archival anonymous skeletal material are weighed against indiscriminate reburial. Although any use of unconsented material represents ethical compromise, account should be taken of changing ethical expectations with time. It is concluded that: there is no justification for repatriation or disposal of all bones for which specific informed consent has not been obtained; continued use of anonymous archival human bones in a professional setting is acceptable, even in the absence of informed consent, with the proviso that there are no culturally relevant groups seeking repatriation; the continued existence of bones in long-standing private collections cannot be justified since it amounts to long-term storage with no identified goals; the notion that 3D images are an ethically superior alternative to actual human bones is unsustainable, since there is an intimate connection between the bones and the 3D images.