Three-dimensional Model Reconstruction Research Articles

From Diagnosis to Precision Surgery: The Transformative Role of Artificial Intelligence in Urologic Imaging.

The multidisciplinary nature of artificial intelligence (AI) has allowed for rapid growth of its application in medical imaging. Artificial intelligence algorithms can augment various imaging modalities, such as X-rays, CT, and MRI, to improve image quality and generate high-resolution three-dimensional images. AI reconstruction of three-dimensional models of patient anatomy from CT or MRI scans can better enable urologists to visualize structures and accurately plan surgical approaches. AI can also be optimized to create virtual reality simulations of surgical procedures based on patient-specific data, giving urologists more hands-on experience and preparation. Recent development of artificial intelligence modalities, such as TeraRecon and Ceevra, offer rapid and efficient medical imaging analyses aimed at enhancing the provision of urologic care, notably for intraoperative guidance during robot-assisted radical prostatectomy (RARP) and partial nephrectomy.

Patient-specific cerebral 3D vessel model reconstruction using deep learning.

Three-dimensional vessel model reconstruction from patient-specific magnetic resonance angiography (MRA) images often requires some manual maneuvers. This study aimed to establish the deep learning (DL)-based method for vessel model reconstruction. Time of flight MRA of 40 patients with internal carotid artery aneurysms was prepared, and three-dimensional vessel models were constructed using the threshold and region-growing method. Using those datasets, supervised deep learning using 2D U-net was performed to reconstruct 3D vessel models. The accuracy of the DL-based vessel segmentations was assessed using 20 MRA images outside the training dataset. The dice coefficient was used as the indicator of the model accuracy, and the blood flow simulation was performed using the DL-based vessel model. The created DL model could successfully reconstruct a three-dimensional model in all 60 cases. The dice coefficient in the test dataset was 0.859. Of note, the DL-generated model proved its efficacy even for large aneurysms (> 10mm in their diameter). The reconstructed model was feasible in performing blood flow simulation to assist clinical decision-making. Our DL-based method could successfully reconstruct a three-dimensional vessel model with moderate accuracy. Future studies are warranted to exhibit that DL-based technology can promote medical image processing.

Assessment of cerebral venous sinus: Anatomical and functional diagnostic performance of three-dimensional reconstruction models based on venous sinus MRI and CT images

Venous sinus stenosis is commonly observed in patients presenting with pulsatile tinnitus (PT). While magnetic resonance imaging (MRI) and computed tomography (CT) are commonly used for assessing venous sinus geometries, the preferred modality remains unclear. In this study, we reconstructed the three-dimensional (3D) geometries of the venous sinus using MRI and CT imaging data from 20 PT patients. We conducted comparisons of the anatomical features of the venous sinus through case-wise analysis and anatomic geometrical parameter-wise analysis. Our findings indicate that by taking the geometries from CT as a reference, MRI could provide a better illustration of venous structure, primarily due to a stronger flow signal concentrated in the vascular tree. We observed high agreements in anatomic parameters measured from 3D geometries reconstructed based on CT and MRI in 19 out of 20 cases. Notably, the cross-sectional area of the sinus and segment length displayed the highest consistency, with a mean difference of -5.01% and 6.5% between modalities, respectively. In addition, we noticed that 55% of cases exhibited consistency in analyzing the confluence of the sinus, while variants of connectivity and collateral branching were observed between CT and MRI. Importantly, CT-based geometric reconstruction provided better detail of inflow side branches in the straight sinus, whereas MRI preserved more side branches of outflow in the downstream sinus. It is important to note that CT-based evaluation may be affected by the bone structures surrounding the venous sinus, whereas MRI-based evaluation focuses on blood flow to the segments, potentially indicating both anatomical and functional abnormalities.

WITHDRAWN: Coronary artery segmentation based on ACMA-Net and unscented Kalman filter algorithm

Accurate segmentation of coronary arteries is a prerequisite for high-precision reconstruction of three-dimensional (3D) models of coronary arteries. With personalized 3D coronary anatomy, clinicians can more readily visually determine the location, type, and severity of a stenotic lesion. However, due to the complex structure and small size of coronary arteries, and the interference of image acquisition conditions, 3D models of segmented and reconstructed coronary arteries are noisy and prone to disconnection; accurate segmentation of coronary arteries is still a challenge.To overcome the above challenges, this study proposes a two-stage coronary segmentation algorithm. In the first stage, we added an atrous convolution feature fusion module (ACFFM) and a multi-axis attention module (MAM) to 3D U-Net, referred to as ACMA-Net, to enhance the feature expression ability of the network and effect the preliminary segmentation of coronary arteries. In the second stage, the preliminary segmentation results were skeletonized and endpoint detection was performed. The regions of coronary artery disconnection were determined by finding the minimum distance between the main trunk branch and the endpoint of each disconnected branch. The disconnected skeleton was repaired by reconnection using an unscented Kalman filter (UKF) algorithm.On the private CORO dataset and the public ASOCA dataset, our method obtains an average Dice coefficient of 0.818 and 0.731, respectively, so it outperforms most of the state-of-the-art algorithms compared, proving its excellent effectiveness and robustness.

Extra-articular screw placement strategy in Stoppa approach based on three-dimensional reconstruction model

The study aimed to explore an extra-articular screw placement strategy in Stoppa approach. Radiographic data of patients who underwent pelvic computed tomography from January 2016 to June 2017 were imported into Materiaise’s interactive medical image control system software for three-dimensional reconstruction. Superior and lower margins of acetabulum and ipsilateral pelvic brim could be observed simultaneously through inlet-obturator view. A horizontal line from superior acetabular margin intersected pelvic brim at point “A” and another vertical line from lower margin intersected pelvic brim at point “B” were drawn, respectively. Lengths form sacroiliac joint to “A” (a), “A” to “B” (b), and “B” to pubic symphysis (c) were measured. Patients were divided into four groups depending on gender and side difference of measured hemi-pelvis: male left, male right, female left, and female right. Lengths of adjacent holes (d) and spanning different holes (e) of different plates were also measured. Mean lengths of a, b, c in four groups were 40.94 ± 1.85 mm, 40.09 ± 1.93 mm, 41.78 ± 3.62 mm, and 39.77 ± 2.23 mm (P = 0.078); 40.65 ± 1.58 mm, 41.48 ± 1.64 mm, 40.40 ± 1.96 mm, and 40.66 ± 1.70 mm (P = 0.265); 57.03 ± 3.41 mm, 57.51 ± 3.71 mm, 57.84 ± 4.40 mm, and 59.84 ± 4.35 mm (P = 0.165), respectively. Mean d length of different plates was 12.23 mm. Average lengths spanning 1, 2, 3 and 4 holes were 19.33 mm, 31.58 mm, 43.80 mm, and 55.93 mm. Our data showed that zones a and c could be safely inserted three and four screws. Penetration into hip joint could be avoided when vacant 3-hole drilling was conducted in zone b. Fracture line in zone b could serve as a landmark for screw placement.

Correlation between femoral offset, rotation center and leg length discrepancy after total hip arthroplasty based on digital analysis

CT scans combined with Mimics software were used to measure femoral offset (FO), rotation center height (RCH) and lower leg length discrepancy (LLD) following total hip arthroplasty (THA), and the relationship between FO, RCH and LLD after THA is discussed. Retrospective analysis was performed on 40 patients with unilateral THA who met standard cases from October 2020 to June 2022. There were 21 males and 19 females, 18 patients on the left side and 22 patients on the right side, aged range from 30 to 81 years old, with an average age of (58.90 ±14.13) years old, BMI ranged from 17.3 to 31.5 kg·m-2 with an average of (25.3±3.4) kg·m-2. There were 30 cases of femoral head necrosis (Ficat type Ⅳ), 2 cases of hip osteoarthritis (Tönnis type Ⅲ), 2 cases of developmental hip dislocation combined with end-stage osteoarthritis (Crowe type Ⅲ), and 6 cases of femoral neck fracture (Garden type Ⅳ). Three-dimensional CT reconstruction of pelvis was taken preoperative and postoperative, and three-dimensional reconstruction model was established after processing by Mimics software. FO, RCH and LLD were measured on the model. The criteria for FO reconstruction were as follows:postoperative bilateral FO difference less than 5 mm;the standard for equal length of both lower limbs was as follows:postoperative LLD difference less than 5 mm. Bilateral FO difference was positively correlated with LLD (r=0.744, P<0.001). Chi-square test was performed between the FO reconstructed group and the non-reconstructed eccentricity group:The results showed that the isometric ratio of lower limbs in the FO reconstructed group was significantly higher than that in the FO reconstructed group (χ2=6.320, P=0.012). The bilateral RCH difference was significantly negatively correlated with LLD(r=-0.877, P<0.001). There is a linear relationship between bilateral FO difference and bilateral RCH difference and postoperative LLD, and the linear regression equation is satisfied:postoperative LLD=0.038x-0.099y+0.257(x:postoperative bilateral FO difference, y:postoperative bilateral RCH difference; Unit:cm), F=77.993, R2=0.808, P=0.009. After THA, LLD increased with the increase of FO and decreased with the increase of RCH. The effect of lower limb isometric length can be obtained more easily by reconstruction of FO. There is a linear relationship between the bilateral FO difference and the bilateral RCH difference after THA and LLD, and the regression equation can provide a theoretical reference for judging LLD.

Investigation of three-dimensional model reconstruction and fractal characteristics of crack propagation in jointed sandstone

The presence of random joints, cracks, and other defects significantly affects the meso-damage mechanism and macro-mechanical behavior of the rock. This study employed micro-CT scanning, digital image processing (DIP), and the rock failure process analysis system (RFPA3D) to reconstruct a genuine mesostructure, creating a three-dimensional (3D) numerical model of jointed sandstone. Under uniaxial stress, this model facilitated the meso-damage evolution process of prefabricated cracks in sandstone with varying dip angles. Additionally, the influence of jointed sandstone heterogeneity and prefabricated cracks with various dip angles on its failure mode and meso-damage mechanical properties were investigated. Utilizing the MATLAB platform, a 3D box dimension algorithm was developed to analyze the fractal characteristics of the mesodamage evolution in the sample. This algorithm enabled the quantitative characterization of the meso-damage evolution of sandstone. This study categorized three types of sandstone final failure modes: composite shear failure, shear failure along the joint surface, and tensile failure. Additionally, linear variations in the elastic modulus and compressive strength of the jointed sandstone were observed with increasing prefabricated fracture inclination, highlighting significant anisotropy. The presence of joints was found to induce and control the failure mode of sandstone. The meso-damage evolution process of sandstone was described in terms of the fractal dimension, indicating that more severe damage corresponded to a larger fractal dimension. This approach offers a novel statistical method for studying the progression of rock damage.

Influence of coal-rock interface inclination on the damage and failure law of original coal-rock combination

In recent years, China's coal mines have gradually entered into deep mining. Ensuring safe and efficient extraction of deep coal resources has emerged as a key concern in the coal mining industry. The characteristics of the coal-rock interface play a significant role in influencing the damage and failure of the coal-rock combination. In order to deeply study the influence of interface inclination on the damage and failure law of the primary coal-rock combination, this paper successfully established the three-dimensional reconstruction model of the coal-rock combination with 5 different inclination angles (0°, 30°, 45°, 60°, 90°) by combining CT technology and AVZIO software. Then PFC2D software was used to simulate the damage and failure of coal-rock combination under different interface angles. The results show that: the loading damage characteristics of coal-rock combinations with different dip angles are similar, that is, the fracture evolution of coal-rock bodies is mainly concentrated in the coal bodies, and the damage and failure of coal-rock interfaces are the most severe. In the early stage of the loading damage, the fractal dimension of the coal-rock combination increases with the increase of interfacial inclination, but the growth rate of the fractal dimension shows a decreasing tendency with the increase of interfacial inclination. With the increase of the inclination angle of the interface of the assemblage, the growth rate of the acoustic emission signal and the total cumulative acoustic emission of the coal-rock combination show a tendency of increasing firstly, then decreasing and then increasing again. The porosity near the coal-rock interface is relatively large when the coal-rock combination is damaged by a load.

Differences and Correlations of Morphological and Hemodynamic Parameters between Anterior Circulation Bifurcation and Side-wall Aneurysms.

The objective of this research was to explore the difference and correlation of the morphological and hemodynamic features between sidewall and bifurcation aneurysms in anterior circulation arteries, utilizing computational fluid dynamics as a tool for analysis. In line with the designated inclusion criteria, this study covered 160 aneurysms identified in 131 patients who received treatment at Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, China, from January 2021 to September 2022. Utilizing follow-up digital subtraction angiography (DSA) data, these cases were classified into two distinct groups: the sidewall aneurysm group and the bifurcation aneurysm group. Morphological and hemodynamic parameters in the immediate preoperative period were meticulously calculated and examined in both groups using a three-dimensional DSA reconstruction model. No significant differences were found in the morphological or hemodynamic parameters of bifurcation aneurysms at varied locations within the anterior circulation. However, pronounced differences were identified between sidewall and bifurcation aneurysms in terms of morphological parameters such as the diameter of the parent vessel (Dvessel), inflow angle (θF), and size ratio (SR), as well as the hemodynamic parameter of inflow concentration index (ICI) (P<0.001). Notably, only the SR exhibited a significant correlation with multiple hemodynamic parameters (P<0.001), while the ICI was closely related to several morphological parameters (R>0.5, P<0.001). The significant differences in certain morphological and hemodynamic parameters between sidewall and bifurcation aneurysms emphasize the importance to contemplate variances in threshold values for these parameters when evaluating the risk of rupture in anterior circulation aneurysms. Whether it is a bifurcation or sidewall aneurysm, these disparities should be considered. The morphological parameter SR has the potential to be a valuable clinical tool for promptly distinguishing the distinct rupture risks associated with sidewall and bifurcation aneurysms.

Grey Wolf Optimizer with Behavior Considerations and Dimensional Learning in Three-Dimensional Tooth Model Reconstruction.

Three-dimensional registration with the affine transform is one of the most important steps in 3D reconstruction. In this paper, the modified grey wolf optimizer with behavior considerations and dimensional learning (BCDL-GWO) algorithm as a registration method is introduced. To refine the 3D registration result, we incorporate the iterative closet point (ICP). The BCDL-GWO with ICP method is implemented on the scanned commercial orthodontic tooth and regular tooth models. Since this is a registration from multi-views of optical images, the hierarchical structure is implemented. According to the results for both models, the proposed algorithm produces high-quality 3D visualization images with the smallest mean squared error of about 7.2186 and 7.3999 μm2, respectively. Our results are compared with the statistical randomization-based particle swarm optimization (SR-PSO). The results show that the BCDL-GWO with ICP is better than those from the SR-PSO. However, the computational complexities of both methods are similar.

Research on Secondary Innovation Design of Valve Products based on 3D Printing Technology and Reverse Engineering

This study will take simple valves as the research object, the data extraction of some parts of valves, explore the research idea of three-dimensional model reconstruction of valves based on reverse engineering technology using forward and reverse integration modeling method, and deeply analyze the application prospect of 3D printing technology and reverse engineering technology in the valve industry. For domestic and foreign valve product users to provide rapid prototyping, secondary innovation design can be used for reference ideas.

Which Skeletal Factors Can Affect Lip Canting in Facial Asymmetry?: Statistical Analysis.

Lip canting, which is a noticeable factor in patients with facial asymmetry, can be influenced by the dentofacial skeleton. During orthognathic surgery, postoperative changes in facial soft tissue occur along the newly positioned hard tissue. Therefore, the evaluation of soft tissue before surgery is important. The purpose of this study was to investigate the skeletal factors that can affect lip canting by statistically comparing 2 facial horizontal planes using a three-dimensional reconstruction model. The findings of the present study showed a statistical correlation between lip canting and 3 skeletal factors: menton deviation, maxillary canting, and ramal length differences. Furthermore, a statistical correlation was identified between the Frankfort Horizontal plane and the intercanthal plane compared with the lip canting line. This result suggests that the intercanthal plane could be a standard horizontal plane in three-dimensional reconstruction model analysis.

Three-Dimensional Reconstruction of Railway Bridges Based on Unmanned Aerial Vehicle–Terrestrial Laser Scanner Point Cloud Fusion

To address the incomplete image data collection of close-to-ground structures, such as bridge piers and local features like the suspension cables in bridges, obtained from single unmanned aerial vehicle (UAV) oblique photography and the difficulty in acquiring point cloud data for the top structures of bridges using single terrestrial laser scanners (TLSs), as well as the lack of textural information in TLS point clouds, this study aims to establish a high-precision, complete, and realistic bridge model by integrating UAV image data and TLS point cloud data. Using a particular large-scale dual-track bridge as a case study, the methodology involves aerial surveys using a DJI Phantom 4 RTK for comprehensive image capture. We obtain 564 images circling the bridge arches, 508 images for orthorectification, and 491 images of close-range side views. Subsequently, all images, POS data, and ground control point information are imported into Context Capture 2023 software for aerial triangulation and multi-view image dense matching to generate dense point clouds of the bridge. Additionally, ground LiDAR scanning, involving the placement of six scanning stations both on and beneath the bridge, was conducted and the point cloud data from each station are registered in Trimble Business Center 5.5.2 software based on identical feature points. Noise point clouds are then removed using statistical filtering techniques. The integration of UAV image point clouds with TLS point clouds is achieved using the iterative closest point (ICP) algorithm, followed by the creation of a TIN model and texture mapping using Context Capture 2023 software. The effectiveness of the integrated modeling is verified by comparing the geometric accuracy and completeness of the images with those obtained from a single UAV image-based model. The integrated model is used to generate cross-sectional profiles of the dual-track bridge, with detailed annotations of boundary dimensions. Structural inspections reveal honeycomb surfaces and seepage in the bridge piers, as well as painted rust and cracks in the arch ribs. The geometric accuracy of the integrated model in the X, Y, and Z directions is 1.2 cm, 0.8 cm, and 0.9 cm, respectively, while the overall 3D model accuracy is 1.70 cm. This method provides technical reference for the reconstruction of three-dimensional point cloud bridge models. Through 3D reconstruction, railway operators can better monitor and assess the condition of bridge structures, promptly identifying potential defects and damages, thus enabling the adoption of necessary maintenance and repair measures to ensure the structural safety of the bridges.

Technology in the Administration of Justice: Forensic Scene Research in International Approach

Technology begins to play a leading role in the administration of justice, in particular in case of complex proceedings, to which basic forensic methods, techniques and tools have not yet been applied. Humans as an end users of a computer software more and more often use highly specialized software in daily work, thanks to which a number of further analyses can be performed. Such operations, the vast majority of which have been forwarded from competent foreign institutions, are conducted by domestic centres with the application of the latest achievements in forensic science. Recent efforts aimed at introducing commercial services (also made available for use by public institutions) to the market of solutions for the study of sceneprompted the author to scientifically analyse the use of modern technologies in forensic science, with particular emphasis on the crime scene (being the place where traces are discovered and evidence is secured) for the purposes of proceedings conducted by competent law enforcement institutions. Thus, the study can be deemed original and its purpose is to fill the cognitive gap in the indicated scope.Individual sections of the article are devoted to the indication of the role that photography plays in forensic science, issues related to satellite imaging, creation of threedimensional reconstruction models of crime scenes using scanning technology, with an emphasis on the role played by artificial intelligence algorithms in this process as well. As a research thesis, an assumption was made that scene research (its detailed scope, correctness, duration, the possibility of conducting analyses, drawing conclusions), necessary to adequately secure the crime scene, is not independent of the progress of technology. The study includes both theoretical considerations, for which an analysis of Polish and foreign language sources was used, as well as focuses on presenting practical possibilities of applying the described tools. The issue raised remains up-to-date, in particular given the need to seek international opportunities to use the latest, constantly developing technologies for the purpose of conducting criminal proceedings. This focus contributes to the presentation of a comprehensive study, for which a qualitative descriptive method supported by a critical analysis of sources has been used. The article also contains final conclusions and research postulates, including de lege ferendalegislative suggestions.

Three-Dimensional Customized Imaging Reconstruction for Urological Surgery: Diffusion and Role in Real-Life Practice from an International Survey.

Despite the arising interest in three-dimensional (3D) reconstruction models from 2D imaging, their diffusion and perception among urologists have been scarcely explored. The aim of the study is to report the results of an international survey investigating the use of such tools among urologists of different backgrounds and origins. Beyond demographics, the survey explored the degree to which 3D models are perceived to improve surgical outcomes, the procedures mostly making use of them, the settings in which those tools are mostly applied, the surgical steps benefiting from 3D reconstructions and future perspectives of improvement. One hundred responders fully completed the survey. All levels of expertise were allowed; more than half (53%) were first surgeons, and 59% had already completed their training. Their main application was partial nephrectomy (85%), followed by radical nephrectomy and radical prostatectomy. Three-dimensional models are mostly used for preoperative planning (75%), intraoperative consultation and tailoring. More than half recognized that 3D models may highly improve surgical outcomes. Despite their recognized usefulness, 77% of responders use 3D models in less than 25% of their major operations due to costs or the extra time taken to perform the reconstruction. Technical improvements and a higher availability of the 3D models will further increase their role in surgical and clinical daily practice.

Finite Element Parametric Design of Hallux Valgus Orthosis Based on Orthogonal Analysis.

To design appropriate orthosis for hallux valgus, a difficult foot condition that affects a quarter of the body's bones, we need to clarify the numerical biomechanical features, which have not been established in previous biomechanical studies. Therefore, we constructed a finite element model of the bunion foot to investigate the orthopaedic force compensation mechanism. A patient with moderate hallux valgus was recruited. CT imaging data in DICOM format were extracted for three-dimensional foot model reconstruction. In conjunction with the need for rapid design of bunion orthosis, a metatarsal force application sizing method based on an orthogonal test design was investigated. The orthogonal test design was used to obtain the hallux valgus angle (HVA) and the inter metatarsal angle (IMA) data for different force combinations. Based on the extreme difference analysis and analysis of variance of the test results, the influence of different force combinations on the bunion angle was quickly determined. The results showed that the stress concentration occurred mainly in the first metatarsal bone. The distribution trend was in the medial and lateral middle of the bone and gradually decreased to the dorsal base of the bone body. The greatest stress occurs in the cartilage between the phalanges and metatarsals. In 25 groups of simulation experiments, HVA was reduced from 27.7° to 13°, and IMA was reduced from 12.5° to 7.3°. Applying detailed orthopaedic force collocation to the first metatarsal column can effectively restore the mechanics and kinematics of hallux valgus, and provide a reference for the treatment of bunion valgus and the design of orthopaedic devices.

Hierarchical Edge-Preserving Dense Matching by Exploiting Reliably Matched Line Segments

Image dense matching plays a crucial role in the reconstruction of three-dimensional models of buildings. However, large variations in target heights and serious occlusion lead to obvious mismatches in areas with discontinuous depths, such as building edges. To solve this problem, the present study mines the geometric and semantic information of line segments to produce a constraint for the dense matching process. First, a disparity consistency-based line segment matching method is proposed. This method correctly matches line segments on building structures in discontinuous areas based on the assumption that, within the corresponding local areas formed by two corresponding line pairs, the disparity obtained by the coarse-level matching of the hierarchical dense matching is similar to that derived from the local homography estimated from the corresponding line pairs. Second, an adaptive guide parameter is designed to constrain the cost propagation between pixels in the neighborhood of line segments. This improves the rationality of cost aggregation paths in discontinuous areas, thereby enhancing the matching accuracy near building edges. Experimental results using satellite and aerial images show that the proposed method efficiently obtains reliable line segment matches at building edges with a matching precision exceeding 97%. Under the constraint of the matched line segments, the proposed dense matching method generates building edges that are visually clearer, and achieves higher accuracy around edges, than without the line segment constraint.

Study of rock damage characteristics in decoupled slit charge blasting based on computer tomography scanning

Controlling blast load damage and destruction of the remaining rock mass in rock blasting has been the focus of scientific research. By studying various decoupling ratios of the slit charges, blasting experiments and numerical calculations of the small charge were carried out on the glauconite specimen. The internal fracture and damage characteristics of the damaged specimens (post blast) were quantified by computed tomography (CT) scanning and three-dimensional (3D) model reconstruction. The results showed that the damage to the glauconite specimens was mainly radial, with the main crack surface in the slit direction and the “X-type” and “Y-type” non-slit directions. With the increase in the decoupling ratio of the slit charge, the fractal dimension of the explosion crack face tends to increase, and the degree of damage gradually increased; When the decoupling ratio was 1.67, the fractal dimension of the explosive crack surface decreased, the smallest degree of damage. LS-DYNA simulation software was used to study the dynamic fracture process and the effective stress peak of the blasthole wall in the slit and non-slit directions for different decoupling ratios of the slit charge. The numerical calculation results showed that with the increase in the decoupling ratio, the peak effective stress of the blasthole wall characteristic unit in the slit direction was larger than that in the non-slit direction; The effective stress peak showed an increasing trend, and the maximum peak effective stress was 567.7 MPa when the decoupling ratio was 1.67. Therefore, this method can be a suitable means to reconstructing the spatial distribution of internal cracks and numerical calculation to evaluate the damage mechanism of slit charge blasting; Furthermore, within the range of the optimal slit charge decoupling ratio, this method can guide the site to prevent the damage and destruction of the remaining rock mass, allowing for more, allocation and utilization of the explosion energy.

Variation of the stapes and its surrounding anatomical structures based on micro-computed tomography.

Stapedotomy is the most efficient treatment for otosclerosis. The anatomical structure of the operation area is complex, but it has a great impact on the postoperative effect. We measure the anatomical parameters of the stapes and its surrounding structures to provide an anatomical reference for stapes surgery in otosclerosis. Fifteen adult cadaver heads (30 samples) were scanned using micro-CT. The stapes, facial nerve and external auditory canal were reconstructed by image processing. The stapes parameters and relationships between the stapes and surrounding structures were measured using a three-dimensional reconstruction model. The length, width and thickness of the stapes footplate were 2.93 ± 0.17 mm, 1.46 ± 0.08 mm and 0.30 ± 0.11 mm, respectively. The distance between the stapes footplate and long process of the incus was 3.79±0.39 mm. The angle of the incudostapedial joint was 88.29 ± 11.58°. The distance from the center of the stapes footplate to the facial canal was 1.60 ± 0.34 mm. In simulated stapes surgery, the minimum depth of the external auditory canal to be removed was 2.17 ± 0.91 mm, and no significant difference was found between the left and right sides and between men and women (P > 0.05). A three-dimensional model of the stapes bone and its surrounding anatomical structures was established based on Micro-CT imaging. Anatomical parameters of the stapes bone and its surrounding structures were measured using the model. In stapedotomy, the implanted piston diameter should be around 0.6mm, with a length of approximately 4.6mm. Care should be taken to protect the facial nerve canal during the surgery. These data provide reference for otologists.

Age estimation by modified Suchey-Brooks method using three-dimensional reconstructed CT images of Chinese Han population

The method proposed by Suchey-Brooks for adult age estimation based on the surface morphology of the pubic symphysis has been widely accepted. The applicability of the method varies considerably in different populations. The present study established a virtual reference sample and aimed to develop population-specific criteria that can be used for age estimation in different skeletal samples. First, The dry bone specimens from 100 individuals were compared with their corresponding three-dimensional (3D) reconstruction model and showed high inter-method agreement (k = 0.743–0.811), suggesting that the virtual bone model and physical bone specimens have comparable performances in describing the surface morphology of the pubic symphysis. We retrospectively collected clinical computed tomography (CT) data from 895 Chinese patients to create a virtual reference sample of the pubic symphysis. Based on the original Suchey-Brooks method, each of the 895 reference samples was assigned a phase, for each sex and phase, data on the mean age, standard deviation, and 95% age range of the corresponding sample were obtained, which was then used as the “method modified for Chinese” (modified method) and compared to the “SB method”. Compared to the SB method, modified method had a lower inaccuracy in dry bones for males over 35 years and females over 45 years, in dry bone CT test sample for males over 55 years and females over 45 years, and in postmortem CT test sample for males over 35 years and females over 55 years. The modified method can improve the accuracy of age estimation for older samples over 40 years. It has shown considerable reliability when applied as a population-specific criterion, but its accuracy is still not sufficient, and caution is needed when using it.