Exploratory investigation of virtual lesions in gastrointestinal endoscopy using a novel phase-shift method for three-dimensional shape measurement.

Accurate measurement of the size of lesions or distances between any two points during endoscopic examination of the gastrointestinal tract is difficult owing to the fisheye lens used in endoscopy. To overcome this issue, we developed a phase-shift method to measure three-dimensional (3D) data on a curved surface, which we present herein. Our system allows the creation of 3D shapes on a curved surface by the phase-shift method using a stripe pattern projected from a small projecting device to an object. For evaluation, 88 measurement points were inserted in porcine stomach tissue, attached to a half-pipe jig, with an inner radius of 21 mm. The accuracy and precision of the measurement data for our shape measurement system were compared with the data obtained using an Olympus STM6 measurement microscope. The accuracy of the path length of a simulated protruded lesion was evaluated using a plaster model of the curved stomach and graph paper. The difference in height measures between the measurement microscope and measurement system data was 0.24 mm for the 88 measurement points on the curved surface of the porcine stomach. The error in the path length measurement for a lesion on an underlying curved surface was <1% for a 10-mm lesion. The software was developed for the automated calculation of the major and minor diameters of each lesion. The accuracy of our measurement system could improve the accuracy of determining the size of lesions, whether protruded or depressed, regardless of the curvature of the underlying surface.

Three-dimensional ecological drought identification and evaluation method considering eco-physiological status of terrestrial ecosystems.

Ecological drought is a complex process in terrestrial ecosystems where vegetation's eco-physiological functions are impaired due to water stress. However, there is currently a lack of long-term assessment of ecological drought from an eco-physiological perspective. In this study, the standardized ecological drought index (SESNDI) was developed using actual evaporation, root soil moisture, and kernel normalized difference vegetation index via the Euclidean distance method, reflecting ecosystem physiology, water supply capacity, and vegetation status. Solar-induced chlorophyll fluorescence validated SESNDI by reflecting vegetation photosynthesis. Using China as an example, severely impacted by climate change and ecological restoration, ecological drought's spatio-temporal variation and propagation characteristics was evaluated using clustering algorithms. The results demonstrated that (1) SESNDI showed superior performance over several other drought indices. (2) During 1982-2020, ecological drought was prevalent from 1990 to 2010, especially in the central and northeastern regions. (3) Compared to 1982-2000, the median duration and affected area of ecological drought events during 2001-2020 reduced by four months and 1.51 × 105 km2, respectively, while the median intensity increased by 0.06. (4) Decreased precipitation and increased temperature were the primary factors contributing to the frequent occurrence of ecological drought in China from 1990 to 2010. This study offers a crucial methodology for evaluating ecological drought, serving as a reference for developing effective terrestrial restoration strategies.

Three-dimensional pseudocontinuous arterial spin labeling with dual postlabeling delay for reflecting cerebral blood flow regulation in patients with hydrocephalus: a retrospective cross-sectional study.

Background: Three-dimensional pseudo-continuous arterial spin-labeling (3D pCASL) with dual postlabeling delay (PLD) captures both early and delayed cerebral blood flow (CBF), yet its potential in reflecting blood flow regulation in hydrocephalus patients remains uncertain. This study investigated the hemodynamic characteristics in patients with hydrocephalus and whether the difference in cerebral blood flow using short and long PLDs (ΔCBF = CBFPLD =2.5 s - CBFPLD =1.5 s) could reflect cerebral regulation and further aimed to demonstrate the associations between regional ΔCBF and the degree of ventricular dilatation. Methods: This retrospective study included consecutive patients with hydrocephalus and control participants attending The Second Affiliated Hospital of Nanchang University from December 2017 to December 2022. The CBF in 18 brain regions was manually delineated by two radiologists. Regional CBF and ΔCBF were compared via covariance analyses. The associations between ΔCBF and the degree of ventricular dilatation were investigated using linear regression analyses and interaction analysis. Results: In total, 58 patients with communicating hydrocephalus, 57 patients with obstructive hydrocephalus, and 52 controls were analyzed. CBF of the hydrocephalus groups was lower than that of the control group at the shorter PLD. CBF was higher at a longer PLD, with no difference between the hydrocephalus groups and the control group in some regions. The hydrocephalus groups showed a higher ΔCBF compared to the control group. Furthermore, in the left medial watershed (10.6±5.66 vs. 7.01±5.88 mL/100 g/min; P=0.038), communicating hydrocephalus exhibited greater ΔCBF than did obstructive hydrocephalus. ΔCBF of the right posterior external watershed [adjusted ß: 0.276; 95% confidence interval (CI): 0.047-0.505; P=0.019] and right parietal cortex (adjusted ß: 0.277; 95% CI: 0.056-0.498; P=0.015) in the obstructive hydrocephalus group and ΔCBF of the left internal watershed (adjusted ß: 0.274; 95% CI: 0.013-0.536; P=0.040) in the communicating hydrocephalus group were associated with the degree of ventricular dilatation, respectively. Conclusions: Patients with hydrocephalus showed cerebral regulation in maintaining adequate CBF, resulting in longer arterial transit times. The ability to regulate CBF in brain regions represented by the watershed was associated with the degree of ventricular dilation.

Novel techniques and future developments in minimally invasive pectus repair.

After the paradigm shift in the treatment of excavated deformities caused by the introduction of the Nuss technique in 1998, several innovative technical modifications and new treatment modalities have radically changed the surgical approach of pectus excavatum in the last couple of years. These new trends attain different topics. On one hand, the use of three-dimensional (3D) printing and implant customization surge as a possibility for a wider audience as 3D printers become available with lower costs. They provide the surgeon with new elements that enable precise planning, simulation, and customized prostheses amidst a tendency to abandon standardization and incorporate personalized medicine. Another topic comprises mandatory sternal elevation, in the continuous search for safety first always. Complete thoracic remodeling as a goal of repair instead of addressing only focal depressions, leaving the upper chest or focal protrusions unresolved. Finally, although the current surgical approach has evolved significantly, many groups still use lateral stabilizers or direct implant fixation with sutures or wires to the ribs. These systems continue to prove unreliable in preventing implant displacement. Fortunately, the bridge technique, described in this review, has come to address this sometimes fatal issue with encouraging results. We provide an updated overview of the latest developments regarding these concepts, related to the current state-of-the-art of the treatment of pectus excavatum.

Application of three-dimensional printed models with near-infrared fluorescence technology in video-assisted thoracoscopic surgery segmentectomy: a single-center propensity-score matching analysis.

Background: The combination of three-dimensional printing (3DP) technology and near-infrared fluorescence (NIF) technology using indocyanine green (ICG) has demonstrated significant potential in enhancing surgical margin and safety, as well as simplifying segmental resection. However, there is limited literature available on the integrated use of these techniques. The current study assessed the effectiveness and value of integrating 3DP-NIF technologies in the perioperative outcomes of thoracoscopic segmental lung resection. Methods: This single-center, retrospective study recruited 165 patients with pulmonary nodules who underwent thoracoscopic segmentectomy. Eligible patients were categorized into two groups: the 3DP-NIF group (71 patients) treated with a combination of 3DP-NIF technology, and the three-dimensional computed tomography bronchography and angiography with modified inflation-deflation (3D-CTBA-ID) group (94 patients). Following rigorous propensity-score matching (PSM) analysis (1:1 ratio), perioperative outcomes between these two approaches were compared. Results: Sixty-six patients were successfully matched in each group. In the 3D-CTBA-ID group, inadequate visualization of segmental planes was noted in 14 cases, compared to only five cases in the 3DP-NIF group (P=0.03). In addition, the 3DP-NIF group demonstrated a shorter time for clear intersegmental boundary line (IBL) presentation {9 [8, 10] vs. 1,860 [1,380, 1,920] s} (P<0.001), and shorter operative time (134.09±34.9 vs. 163.47±49.4 min) (P<0.001), postoperative drainage time (P<0.001), and postoperative hospital stay (P=0.002) compared to the 3D-CTBA-ID group. Furthermore, the incidence of postoperative air leak was higher in the 3D-CTBA-ID group than in the 3DP-NIF group (33.3% vs. 7.6%, P<0.001). Conclusions: The combination of 3DP-NIF technologies served as a reliable technical safeguard, ensuring the safe and efficient execution of thoracoscopic pulmonary segmentectomy.

Design of Three-Dimensional Mesoporous Adamantane-Based Covalent Organic Framework with Exceptionally High Surface Areas.

The development of three-dimensional (3D) covalent organic frameworks (COFs) with large pores and high specific surface areas is of critical for practical applications. However, it remains a tremendous challenge to reconcile the contradiction between high porosity and high specific surface areas, and increasing the length of building blocks leads to structural interpenetration in 3D COFs. Here, we report the preparation of mesoporous three-dimensional COF by a new steric hindrance engineering method. By incorporating adamantane into the monomers instead of carbon centers, we successfully achieve 2-fold interpenetrated diamondoid-structured 3D COFs, featuring permanent mesopores (up to 33 Å), exceptionally high surface areas (>3400 m2 g-1), and low crystal densities (0.123 g cm-3). These properties far surpass those of most conventional 3D COFs with similar topologies. This work not only aims to construct 3D COFs with low interpenetration but also to establish a foundation for the systematic design and structural control of 3D COFs.

Multivariable linear model for predicting graft weight based on 3-dimensional volumetry in regards to body weight change of living liver donor: an observational cohort study.

Purpose: The purpose of this study is to build a prediction model for estimating graft weight about different graft volumetry methods combined with other variables. Methods: Donors who underwent living-donor right hepatectomy from March 2021 to March 2023 were included. Estimated graft volume measured by conventional method and 3-dimensional (3D) software were collected as well as the actual graft weight. Linear regression was used to build a prediction model. Donor groups were divided according to the 3D volumetry of <700 cm3, 700-899 cm3, and ≥900 cm3 to compare the performance of different models. Results: A total of 119 donors were included. Conventional volumetry showed R2 of 0.656 (P < 0.001) while 3D software showed R2 of 0.776 (P < 0.001). The R2 of the multivariable model was 0.842 (P < 0.001) including for 3D volume (ß = 0.623, P < 0.001), body mass index (ß = 7.648, P < 0.001), and amount of weight loss (ß = -7.252, P < 0.001). The median errors between different models and actual graft weight did not differ in donor groups (<700 and 700-899 cm3), while the median error of univariable linear model using 3D software (122.5; interquartile range [IQR], 61.5-179.8) was significantly higher than multivariable-adjusted linear model (41.5; IQR, 24.8-69.8; P = 0.003) in donors with estimated graft weight ≥900 cm3. Conclusion: The univariable 3D volumetry model showed an acceptable outcome for donors with an estimated graft volume <900 cm3. For donors with an estimated graft volume ≥900 cm3, the multivariable-adjusted linear model showed higher accuracy.

Optimization of transplantation methods using isolated mesenchymal stem/stromal cells: clinical trials of inflammatory bowel diseases as an example.

Mesenchymal stem/stromal cells (MSCs) are distributed in various tissues and are used in clinical applications as a source of transplanted cells because of their easy harvestability. Although MSCs express numerous cell-surface antigens, single-cell analyses have revealed a highly heterogeneous cell population depending on the original tissue and donor conditions, including age and interindividual differences. This heterogeneity leads to differences in their functions, such as multipotency and immunomodulatory effects, making it challenging to effectively treat targeted diseases. The therapeutic efficacy of MSCs is controversial and depends on the implantation site. Thus, there is no established recipe for the transplantation of MSCs (including the type of disease, type of origin, method of cell culture, form of transplanted cells, and site of delivery). Our recent preclinical study identified appropriate MSCs and their suitable transplantation routes in a mouse model of inflammatory bowel disease (IBD). Three-dimensional (3D) cultures of MSCs have been demonstrated to enhance their properties and sustain engraftment at the lesion site. In this note, we explore the methods of MSC transplantation for treating IBDs, especially Crohn's disease, from clinical trials published over the past decade. Given the functional changes in MSCs in 3D culture, we also investigate the clinical trials using 3D constructs of MSCs and explore suitable diseases that might benefit from this approach. Furthermore, we discuss the advantages of the prospective isolation of MSCs in terms of interindividual variability. This note highlights the need to define the method of MSC transplantation, including interindividual variability, the culture period, and the transplantation route.

Visualization of the infratemporal fossa: enhancing anatomical learning through three-dimensional modeling.

The infratemporal fossa and pterygopalatine fossa are critical pathways for blood vessels and nerves leading to the orbit, nasal cavity, and oral cavity. Anatomical observation of these areas is challenging for learners due to their complex connections with surrounding structures and their deep location within the body. Since it is not easy to understand this area in three dimensions with only textbook images, there is a need to produce three-dimensional (3D) content. Most existing 3D data have reconstructed the digital imaging and communication in medicine files from computed tomography images with high accuracy; however, the surrounding structures often obstruct the view. For this reason, this project utilized Cinema4D (R18; Maxon) software to refine the modeled bones and to create 3D models of muscles, blood vessels, and nerves that accurately represent their anatomical shapes and pathways. To facilitate easier access for learners via PC, the content was converted into PDF format. This enables the educational materials to be more easily viewed and the main structures more clearly observed using a computer-based viewer.

Personalized biomodel of the cervical spine for laboratory laminoplasty training.

OBJECTIVE: The use of biomodels in the laboratory for studying and training cervical laminoplasty has not yet been reported. We propose the use of a cervical spine biomodel for surgical laminoplasty training. METHODS: This is an experimental study. Ten 3D identical cervical spine biomodels were printed based on CT and MRI scans of a patient diagnosed with spondylotic cervical myelopathy. The additive manufacturing method employed fused deposition modeling (FDM) and polylactic acid (PLA) and selected as the raw material. The sample was divided into two groups: control (n = 5; the biomodels were submitted to CT scanning) and open-door (n = 5; the biomodels were submitted to open-door laminoplasty and postoperative CT). The area and anteroposterior diameter of the vertebral canal were measured on CT scans. RESULTS: Printing each piece took twelve hours. During the surgical procedure, there was sufficient support from the biomodels to keep them immobilized. Using the drill was feasible; however continuous irrigation was mandatory to prevent plastic material overheating. The raw material made the biomodel CT study possible. The vertebral canal dimensions increased 24.80% (0.62 cm2) in the area and 24.88% (3.12 mm) in the anteroposterior diameter. CONCLUSIONS: The cervical spine biomodels can be used for laminoplasty training, even by using thermosensitive material such as PLA. The use of continuous irrigation is essential while drilling.

Developmental three-dimensional examination of the pelvic cavity of Hamdani crossbred sheep fetuses (Ovis aries) in the last two periods of gestation.

BACKGROUND: Türkiye is a country in the world ranking in terms of sheep breeding. Hamdani crossbred sheep breed is one of the sheep breeds that can adapt to the difficult conditions in our country. In addition, the sentence may be corrected as 'Especially in the southeastern part of the Türkiye, crossbreeding is preferred by breeders to increase the yield characteristics of sheep'. OBJECTIVES: In our study, it was aimed to perform a pelvimetric analysis of Hamdani crossbred sheep fetuses in the second and third trimesters by three-dimensional modelling method. METHODS: For this purpose, a total of 40 second-trimester (10 females, 10 males) and third-trimester (10 females, 10 males) fetuses were used. The pelvises of the fetuses were imaged with CT and 3D models were created. Sixteen pelvimetric measurements were performed from the models. The results obtained were evaluated statistically. RESULTS: The study found statistically significant differences between male and female fetuses in terms of vertical diameter (VD) and foramen obturatum width (FOW) measurement parameters in the second trimester. In the third trimester, there were statistically significant differences between genders in acetabulum (AC) (p < 0.01), medial ischial tuberosities (MIT), and ischiatic arch (IA) (p < 0.05) parameters. As a result of the correlation analysis, it was determined that the pelvis length (PL) measurement parameter was positively correlated with different parameters in varying degrees in both periods, while the IA parameter did not show significant correlations with the other parameter in the last two periods of pregnancy. CONCLUSION: In conclusion, the data obtained will be useful in pelvimetric evaluations of human and animal fetuses, anatomy education, zooarchaeology and taxonomy studies.

Clinical value of low-dose three-dimensional reconstruction by multi-slice spiral computed tomography and by traditional X-ray in the diagnosis of distal radius epiphyseal injury in children.

OBJECTIVE: To compare the clinical value of multi-slice spiral computed tomography (MSCT) low-dose three-dimensional reconstruction and traditional X-ray in the auxiliary diagnosis of distal radius epiphyseal injury in children. METHODS: A retrospective analysis was performed on 105 children with distal radius bone scale injury (classified by Salter-Harris classification) admitted from March 2020 to June 2022. All children underwent MSCT three-dimensional reconstruction examination and traditional X-ray examination. The detection rate of epiphyseal injury of the distal radius was compared, along with the resolution, sensitivity and specificity. The image clarity and display degree of bone structure were analyzed. The radiation dose-related indicators and the time required for diagnosis were compared. RESULTS: The detection rate and diagnostic accuracy of MSCT (100%, 92.38%) was significantly higher than that of X-ray (76.19%, 64.76%). In terms of radiation dose index, the volume dose index CTDI of MSCT ranged from 1-5 mGy while the X-ray group ranged from 5-10 mGy. The dose length product (DLP) value of the MSCT group was lower than in the X-ray group (20-100 mGy·cm vs. 50-150 mGy·cm). The diagnostic scan time for MSCT was shorter than that of conventional X-ray. The acceptance rate with MSCT was 99%, significantly higher than that with conventional X-ray (85%). CONCLUSIONS: Low-dose three-dimensional reconstruction of MSCT in the diagnosis of epiphyseal injury of distal radius in children shows significant advantages over traditional CT in the detection rate, diagnostic accuracy, postoperative reduction quality evaluation, and radiation dose.

Effective degradation of bentazone by two-dimensional and three-phase, three-dimensional electro-oxidation system: kinetic studies and optimization using ANN.

Bentazone is a broad-leaved weed-specific herbicide in the pesticide industry. This study focused on removing bentazone from water using three different methods: a two and three-dimensional electro-oxidation process (2D/EOP and 3D/EOP) with a fluid-type reactor arrangement using tetraethylenepentamine-loaded particle electrodes and an adsorption method. Additionally, we analysed the effects of two types of supporting electrolytes  (Na2SO4 and NaCl) on the degradation process. The energy consumption amounts were calculated to evaluate the obtained results. The degradation reaction occurs 3.5 times faster in 3D/EOP than in 2D/EOP at 6 V in Na2SO4. Similarly, the degradation reaction of bentazone in NaCl occurs 2.5 times faster in 3D/EOP than in 2D/EOP at a value of 7.2 mA/cm2. Removal of bentazone is significantly better in 3D/EOPs than in 2D/EOPs. The use of particle electrodes can significantly enhance the degradation efficiency. The study further assessed the prediction abilities of the machine learning model (ANN). The ANN presented reasonable accuracy in bentazone degradation with high R2 values of 0.97953, 0.98561, 0.98563, and 0.99649 for 2D with Na2SO4, 2D with NaCl, 3D with Na2SO4, and 3D with NaCl, respectively.

Post-operative outcomes of primary benign orbital tumor resection are independent of tumor size and morphology.

KEY POINTS: Using 3D modeling, we studied the influence of orbital tumor morphology on post-operative outcomes. Orbital tumor volume did not influence postoperative complication rates. Less spherical tumors may be correlated with a more extensive surgical approach.

The analysis of different types of anorectal abscesses was conducted using the MRI 3D reconstruction technique.

It has not yet been proven whether sepsis affects the tissue around the anal canal. To address this issue, we established three-dimensional models for various types of anorectal abscesses and utilize 3D reconstruction of Magnetic Resonance Imaging scans to assess the extent of muscle damage caused by anorectal abscesses. Patients diagnosed with anorectal abscess, selected from January 2019 to January 2022 underwent pre- and post-operative scanning of pelvic floor and perianal tissues. The aforementioned structures were segmented for the reconstruction of a three-dimensional visual model and measurement of volumes for the abscess as well as the internal and external sphincters and levator ani muscle. The study included a total of 42 patients. Three-dimensional visualization models were created for different types of anorectal abscesses, including perianal, intersphincteric, ischiorectal, and supralevator abscesses. No statistically significant differences were observed in the volume of the internal sphincter, external sphincter, and levator ani muscle between pre- and post-operative patients. The 3D model of anorectal abscess, reconstructed from MRI data, offers a precise and direct visualization of the anatomical structures associated with various types of anorectal abscesses. The infection did not result in any damage to the internal and external anal sphincter and levator ani muscle.

Three dimensional analysis of factors affecting the prognosis of calcaneal fractures.

PURPOSE: Analyzing the correlation between patients' basic information, three-dimensional parameters after calcaneal fractures, and the prognosis of calcaneal fractures. METHODS: A retrospective analysis was conducted on 43 patients with calcaneal fractures who underwent surgical treatment in the Foot and Ankle Surgery, Xi'an Honghui Hospital, from September 2019 to August 2022. Patient demographics including gender and age were collected, as well as the preoperative posterior articular surface collapse area, number of fracture fragments, length, width, height, and volume of the calcaneus obtained from preoperative three-dimensional imaging. Patients were followed up for VAS, AOFAS, and SF-36 scores. Correlation analysis was performed on the obtained data. RESULTS: All 43 included patients received complete follow-up, including 40 males and 3 females, with an average follow-up time of 35.37 ± 10.73 months, and an average age of 43.98 ± 12.08 years. All patients' VAS, AOFAS, and SF-36 scores at the last follow-up showed no correlation with patient age, gender, or the area of posterior articular collapse, number of fracture fragments, length, width, height, or volume of the calcaneus. CONCLUSIONS: The prognosis of calcaneal fractures is unrelated to three-dimensional factors such as patient age, gender, length, width, height, volume of the calcaneus, area of the posterior joint, and number of fracture fragments.

Management of mandibular angle and body fractures using miniplates and 3D plates.

Mandibular angle fractures have the greatest recorded rate of postoperative complications of any mandibular location and hence they present an especially difficult task for surgeons. Therefore, it is of interest to compare the conventional miniplates and three dimensional (3D) plates in management of mandibular angle fracture and body fractures.60 patients with isolated non-comminuted mandibular angle fractures and body fractures were randomly assigned into two groups by lottery. Utilizing Champy's osteosynthesis standards, group one (n = 30) received treatment with 2-mm standard miniplate and group two (n = 30) had treatment with open reduction and internal fixation utilizing 2-mm 3D locking stainless steel plates. The mean operative time was greater in conventional miniplate category as compared to three dimensional plates. Need for postoperative occlusion correction was lesser n 3 dimensional plate category. The incidence of postoperative infection was comparable in both categories. Incidental tooth damage was lesser in three-dimensional plate's category three-dimensional locking plates are an alternate strategy that has a comparable result profile to miniplates.

How Right is the Right Ventricle in Predicting Cardiac Mortality in Cardiac Failure: A 6-year Prospective Cohort Study.

Aim: Two-dimensional speckle tracking echocardiography (2D-STE) and three-dimensional echocardiography (3DE) may overcome many limitations of the conventional 2D echocardiography (2DE) in assessing right ventricular (RV) function. We sought to determine whether characteristics of the right atrium and right ventricle as measured by 2D-STE and 3DE are associated with cardiac mortality in patients with ischemic heart failure, over a 6-year follow-up. Materials and Methods: The inclusion criteria were ischemic cardiomyopathy with left ventricular ejection fraction of <40% diagnosed using standard 2DE, 2D-STE, and 3DE examination. Patients were followed for 6 years, and cardiac mortality was recorded. Results: The study sample comprised a total of 54 participants. During the period of follow-up, 24% (13/54) died. The 2DE models showed that being older, having a higher body mass index (BMI), having higher systolic pulmonary artery pressure (SPAP), and a lower RV global longitudinal strain were associated with cardiac mortality in our cohort after 6-year follow-up. Finally, the 3DE models showed that in addition to being older, having higher BMI, having a higher SPAP baseline, lower baseline 3DE RV stroke volume, and larger 3DE RV end-diastolic volume and 3DE RV end-systolic volume were associated with cardiac mortality over 6-year follow-up. Conclusion: This study provides evidence that RV dysfunction as seen on 2D-STE and 3DE could be associated with increased risk of cardiac-related mortality in patients with heart failure over 6 years.

Validation of automated registration of intraoral scan onto Cone Beam Computed Tomography for an efficient digital dental workflow.

OBJECTIVE: This study aimed to validate a newly developed automated method (Relu® Creator, Leuven, Belgium) for multimodal registration of intraoral scan (IOS) and Cone Beam Computed Tomography (CBCT). METHODS: Time point-matched IOS and CBCT scans of forty patients with variable dental statuses (natural dentition, partial edentulism, presence of orthodontic brackets) were selected. Three operators registered IOS and CBCT scans using three state-of-the-art softwares for orthodontics and orthognathic surgery (IPS Case Designer Proplan CMF and Dolphin Imaging). Automated registration was compared to expert-performed semi-automated registration. Time consumption, accuracy, and consistency of the proposed method were benchmarked to semi-automated registration using root mean squared error calculations. The robustness of the automated registration was evaluated in relationship to the dental status of the patients in the dataset. RESULTS: On average, automatic registration was 7.3 times faster than semi-automatic registration performed by an expert operator. Automatic registration yielded reliable results with low deviation errors compared to the differently skilled operators and semi-automated software. Automated registration surpassed human variability as expressed in intra- and inter-operator inconsistencies. Neither orthodontic brackets nor edentulism impacted registration accuracy. CONCLUSIONS: The presented automated method for IOS and CBCT registration is faster, equally accurate, and more consistent than semi-automatic registration performed by an expert or an occasional operator. With similar results among cases with different dental statuses, the clinical feasibility of the method is ensured. CLINICAL SIGNIFICANCE: A validated automated registration method provides accurate and fast multimodal image integration without incorporating operator bias at the very start of the digital workflows for dentistry, periodontics, orthodontics and orthognathic surgery.

Impact of an educational intervention utilising a three-dimensional-printed model for ultrasound-guided intra-articular injections of the dislocated shoulder.

OBJECTIVE: Intra-articular injection of local anaesthetic provides safe and effective analgesia for patients with shoulder dislocation. We designed a three-dimensional-printed ultrasound model of the shoulder to educate ED clinicians on use of this technique. We aimed to evaluate the impact of a 1-h training session using this model on participants' knowledge, skills and clinical practice. METHODS: This was a prospective study of the clinicians working at two EDs in New Zealand. Participants (n = 20) took part in a 1-h educational session. We tested participants' performance before the session, afterwards and at 3 months using a 10-point objective structured clinical examination. We reviewed clinical records to determine whether there was increased utilisation of this technique among ED patients before and after the training. RESULTS: There was improvement in participants' OCSE performance (median pre-training score = 4.00, median 3-month post-training score = 7.00, P = 0.044) and self-reported competence and knowledge, which were sustained to the end of the study. There was increased use of intra-articular injection among ED patients with shoulder dislocation: 2 of 68 patients (3%) before and 11 of 76 patients (14.5%) after the study. Notably, most were performed by clinicians who did not take part in the study (n = 9). CONCLUSION: A 1-h training session using a three-dimensional-printed model improved participants objective structured clinical examination performance in ultrasound-guided injection of the shoulder joint. Although there was minimal change in the practice of participating clinicians, overall use of the procedure increased.