Dimensional Reconstruction Techniques Research Articles

The study of DIEA three dimensional reconstruction technique based on CTA in preoperative perforator selection

Preoperative selection of perforator is one of the key steps for successful surgery. The purpose of this study is to simulate the selection process of the perforator of the flap using the 3D models of the deep inferior epigastric artery (DIEA). A retrospective study was performed of women who underwent deep inferior epigastric perforator flap breast reconstruction from January 2011 to July 2021. Construct 3D models of the DIEA using computerized tomography angiography images, and then computational fluid dynamics simulations were performed. Correlation and regression analyses were used to analyze the geometric and hemodynamic parameters. Statistical analysis suggested that the outlet flow was positively correlated with the inlet area (r=0.338, p=0.000), outlet area (r=0.840, p=0.000), the average radius of the perforator (r=0.592, p=0.000), and negatively correlated with the length of perforator(r=-0.210, p=0.024). The results of linear regression analysis showed that the outlet area (p=0.000), the average radius (p=0.000), and the length (p=0.044) of the perforator were the influencing factors on outlet flow. In multiple perforators analysis, there was a significant difference in the total outlet flow among single perforator, double perforators, and triple perforators (p=0.002). The successful implementation of this experiment provides a new approach for the selection of dominant perforators in the future.

The growth of image-related three dimensional reconstruction techniques in deep learning-driven era：a critical summary

The growth of image-related three dimensional reconstruction techniques in deep learning-driven era：a critical summary

A review of three dimensional reconstruction techniques

Three dimensional (3D) modeling is an important stereoscopic representation of an object for multiple viewpoints aggregation and geometrical information. A general 3D modeling pipeline consists of data acquisition, 3D reconstruction and surface reconstruction. The core computational process in 3D modeling is always associated with the 3D reconstruction, which can be categorized into three types, i.e. statistical models, discriminative learning models and generative learning models. Statistical models derive handcrafted feature descriptor from mathematical theory to extract the spatial and geometric features of 3D data. A corresponding matching is performed between multiple viewpoints 3D data to search for the maximum region likelihood across datasets and compute the best match of affine transformation. Discriminative learning models learn spatial coherent of 3D data through data-driven training that leads to the computation of affine transformation with data inferencing. Generative models, on the other hand, have the unsupervised capability of ingesting raw 3D data directly to learn latent representation of input 3D data and later generate ambient output sample from the latent representation. In this paper, a detailed comparison on the three types of 3D reconstruction techniques are reviewed in term of input data structure, correspondence accuracy, precision and recall using four benchmark datasets, i.e. ModelNet10/40, ICL-NUIM, and Semantic3D. The advantages and disadvantages of 3D reconstruction techniques are highlighted for implementation guideline and future improvement.

Complete form factors in Yang-Mills from unitarity and spinor helicity in six dimensions

We present a systematic procedure to compute complete, analytic form factors of gauge-invariant operators at loop level in pure Yang-Mills. We consider applications to operators of the form $\mathrm{Tr}\, F^n$ where $F$ is the gluon field strength. Our approach is based on an extension to form factors of the dimensional reconstruction technique, in conjunction with the six-dimensional spinor-helicity formalism and generalised unitarity. For form factors this technique requires the introduction of additional scalar operators, for which we provide a systematic prescription. We also discuss a generalisation of dimensional reconstruction to any number of loops, both for amplitudes and form factors. Several novel results for one-loop minimal and non-minimal form factors of $\mathrm{Tr}\, F^n$ with $n>2$ are presented. Finally, we describe the \texttt{Mathematica} package \texttt{SpinorHelicity6D}, which is tailored to handle six-dimensional quantities written in the spinor-helicity formalism.

IMAGING STUDY ON LUMBAR PLEXUS BY MINIMALLY INVASIVE LATERAL TRANSPSOAS APPROACH

To analyze the relative position between lumbar plexus and access corridor of minimally invasive lateral transpsoas approach based on magnetic resonance imaging distribution of lumbar plexus by three dimensional reconstruction technique, so as to evaluate approach safety. Three-dimensional fast imaging employing steady-state acquisition sequences of lumbar spine were performed on 71 patients with lumbar degenerative diseases between July 2012 and January 2015. The axial image distance between the anterior edge of lumbar plexus and sagittal central perpendicular line (SCPL) of disc was determined using the distance formula at the mid-disc space from L1, 2 to L4, 5 level. SCPL was drawn perpendicularly to the sagittal plane of intervertebral disc and it passed through its central point, which is initial dilator trajectory for transpsoas approach. With respect to the SCPL of disc, the distance with a positive value indicated neural tissue posterior to it whereas anterior to it represented by a negative value. Various branches of lumbar plexus which passed through the psoas major anterior to the SCPL of disc were identified in 42 (59.2%), 58 (81.7%), and 70 (98.6%) patients at L2, 3, L3, 4, and L4, 5 levels, respectively. It is possible to infer the presence of genitofemoral nerve in accordance with relevant anatomic research. A ventral migration of intrapsoas nerves is identified from L1, 2 to L4, 5 level. All differences between levels were statistically significant (P<0.05). With respect to the SCPL of disc, a pass way of guide wire or a radiographic reference landmark to place working channel, lumbar plexus lie posterior to it from L1, 2 to L3, 4 level and shift anteriorly to it at L4, 5 level, while genitofemoral nerve locate anterior to the SCPL from L2, 3 to L4, 5 level. Neural retraction may take place during sequential dilation of working channel especially at L4, 5 level.

Safety assessment of hepatectomy for huge hepatocellular carcinoma by three dimensional reconstruction technique

To explore the effectiveness of three-dimentional(3D)reconstruction technique in safety assessment of hepatectomy for large hepatocellular carcinoma(HCC). The clinical records of 28 patients who underwent resection of HCC greater than 10 cm in diameter from January 2013 to December 2015 at Department of Hepatic Surgery, Tongji Hospital, Tongji Medical College Huazhong University of Science and Technology were studied retrospectively. All patients underwent enhanced computer tomography (CT), then 3D images of liver and tumor were reconstructed by uploading the CT imaging data to IQQA-Liver system. The individual surgery plan was simulated and liver volume (LV), standard liver volume(LV), tumor volume(TV), functional liver volume(FLV), excised liver volume(ELV), excised functional liver volume (EFLV), residual functional liver volume (RELV) were calculated. Simulated surgery plans were compared with actual procedures. ELV was compared with actual excised liver volume (AELV) by paired Student's t test. Postoperative complications and motility were analyzed. The correlation between TV and EFLV, RFLV, RFLV/FLV, RFLV/SLV were calculated by Spearman test. TV ranged from 202 cm(3) to 2 125 cm(3,) RELV ranged from 401 cm(3) to 1 633 cm(3).There were 13 patients whose RFLV/LV<30% and 28 patients whose RFLV/FLV>30%(34.8%-94.0%). RFLV/SLV ranged from 35.9% to 139.0%.All simulated surgery plans matched with the actual operation procedure. ELV was equal to AELV, which confirmed by the high precision of IQQA-Liver system(t=0.636, P>0.05). No severe complications (hepatic encephalopathy or liver failure) and perioperative death occurred after operation. Positive correlation was observed between TV and RFLV, TV and RFLV/FLV, TV and RFLV/SLV(r=0.641, 0.629 and 0.732, all P<0.01). Negative correlation was observed between TV and EFLV (r=-0.539, P<0.01). 3D reconstruction technique could accurately simulate surgery procedure, calculate liver volume and evaluate the safety of hepatectomy for huge hepatocellular carcinoma. When the anatomical liver resection was performed, the larger tumor volume means the smaller excision functional liver volume and larger residual liver volume.

Structural analysis of theridiid spider's testicular cyst using 3D reconstruction rendering

AbstractA three dimensional reconstruction technique was used for the analysis of a theridiid spider's (Achaearanea tepidariorum) testicular cyst. Although microscopic techniques have greatly improved, most of the information gathered is still based on two‐dimensional images. Particularly in spiders, it is very difficult to count the exact number of sperm in a single cyst, since their spermatogenetic processes takes place within the spherical cysts through the flagellar coiling process. Since morphological features of spider sperm provide detailed information on the whole spermatogenetic processes, we analyzed the exact number of germ cells per cyst in A. tepidariorum through a three‐dimensional image reconstruction technique. For image processing, serially sectioned histological images were scanned using a light microscope and 3D rendering images were reconstructed from these sections. Based on the three dimensional image analysis of the testicular cyst, the number of secondary spermatocytes per cyst was calculated to be 32 (25). Therefore the total number of sperm produced from a single cyst can be calculated as 64 (26), which indicates that a single spermatogonium undergoes four mitotic divisions and an additional two meiotic divisions to produce mature spermatozoa.

Sa1861 Post-Ablation Safety Margin of Radiofrequency Ablation of Hepatocellular Carcinoma: Precise Assessment With a Three Dimensionalreconstruction Technique

cell lines FRH, TFK-1and EGI were examined for basal expression of VEGF, VEGFR1, and VEGFR2 by western blotting (WB). The cells were treated with recombinant human VEGF (rhVEGF), and VEGFR phosphorylation was examined by WB, and cell proliferation was evaluated by BrdU incorpation assay. Cells were then treated with 0, 60, or 120 nM of apatinib for 24 hour, and were assayed for VEGFR signaling and cell proliferation. Finally, FRH cells were inoculated into nude mice for further evaluation for apatinib treatment efficacy in vivo. Results: All three EBDC cell lines expressed VEGF and phosphorylated (p) VEGF receptor 1 (pVEGFR1) and 2 (pVEGFR2). By protein fractionalization, we found that VEGFR1 and VEGFR2 were both present on membrane of these three cells. The rhVEGF promoted phosphorylation of VEGFR1 and VEGFR2 at 30 min (FRH and EGI) or 15 min after treatment. The rhVEGF increased cell proliferation (+16.8%, +13.4% and +20.5% for FRH, TFK and EGI respectively) after 24 hr of treatment, which was prevented by preincubation with VEGFR1 or VEGFR2 neutralizing antibody. Apatinib treatment inhibited the phosphorylation of VEGFR1 and VEGFR2 and cell proliferation in all three cell lines in a dose-dependent fashion. Finally, the apatinib-treated FRH xenograft tumors displayed a substantial delayed growth after one week-treatment. The averages of final tumor volumes were significantly different between the vehicle and apatinib-treated groups after 4 weeks of treatment (P<0.05). Conclusion: VEGF directly activated VEGF receptors on EBDC cells and promoted cancer cell proliferation; apatinib inhibited VEGF signaling and suppressed cell proliferation in vitro and delayed xenograft tumor growth in vivo. These findings support a potential role for apatinib in the treatment of extrahepatic bile duct cancers.

Postmortem 3-D reconstruction of skull gunshot injuries

BackgroundIn cases of severe decomposition or skeletonization of a corpse after cerebral gun shot injury it is difficult to exactly reconstruct the bullet path in the brain. However, in case of murder or homicide this might become necessary to answer forensic questions such as the ability to move or other actions of the victim. Materials and methodsTherefore a method in terms of three dimensional reconstruction technique was developed by fusing computed tomography scans (CT) of the original skull and magnetic resonance images (MRI) of a normal brain of adequate size. Hereby five cases were investigated. ResultsIn three cases an excellent concordance between the reconstructed bullet trajectory and the autopsy reports was achieved. In one case the original brain was not available for CT-scanning due to previous autopsy. However, the findings were in line with the pathology report. In one case there was a difference of about 1–2cm between the original autopsy description and the reconstructed bullet path. This was due to only a part of the skull being available for image reconstruction. ConclusionThe findings suggest that this method can successfully be applied to adequately reconstruct bullet paths in cases of completely skeletonized skulls, but should carefully be used in cases of incomplete skulls.

Identification of the Plastic Behaviour in the Post-Necking Regime Using a Three Dimensional Reconstruction Technique

Nowadays a wide number of constitutive models are available to describe the plastic behaviour of metals at large deformations including anisotropy, strain rate effect, kinematic hardening etc. Often the main limitation to the practical applicability of a model resides in the difficulty of experimentally identifying the constitutive parameters. At large deformations the identification can become very complicated because of the occurrence of instabilities, e.g. localized necking or buckling, which create a complex three-dimensional stress and strain state inside the specimen. In these cases, the identification problem is usually tackled by Finite Element Model Updating where a numerical model of the test is built up and the parameters are iteratively varied to achieve the best agreement with the experiments. Recently it has been demonstrated that the Virtual Fields Method (VFM) can be successfully adopted to solve the identification problem using three dimensional displacement data [Rossi and Pierron, Identification of plastic constitutive parameters at large deformations from three dimensional displacement fields, Comp. Mech., 2011]. This paper presents the first experimental validation of this approach. It deals with the identification of plastic constitutive parameters at large strains looking at the post-necking behaviour of a notched specimen. The experiment consisted in a tensile test performed on a notched specimen obtained from a 3 mm thick sheet of 316L stainless steel. An experimental procedure has been developed to reconstruct the volume deformation history of the specimen during the test. A set of four cameras, two for each side of the specimen, has been used to measure the displacement field on the two faces at the same time using Digital Image Stereo-Correlation. The adopted spatial resolution is good enough to describe the out-of-plane movement which takes place at the surface after the occurrence of necking. Starting from the surface measurements, the volume displacement field inside the specimen has been reconstructed using a non-linear volume interpolation. The procedure as well as the reliability of the reconstruction process is described in the paper. Finally, the three dimensional displacement field is used to identify the parameters of a plastic constitutive model using the VFM. The anisotropy of the sheet metal is also taken into account. The main outcome of the paper is to illustrate that it is possible to retrieve the three dimensional deformation history of a specimen in the post-necking region using surface measurements and that these data can be quantitatively used to identify the constitutive model.

Pointwise Identification of Elastic Properties in Nonlinear Hyperelastic Membranes—Part II: Experimental Validation

Following the theoretical and computational developments of the pointwise membrane identification method reported in the first part of this paper, we perform a finite inflation test on a rubber balloon to validate the method. The balloon is inflated using a series of pressurized configurations, and a surface mesh that corresponds through all the deformed states is derived using a camera-based three dimensional reconstruction technique. In each configuration, the wall tension is computed by the finite element inverse elastostatic method, and the in-plane stretch relative to a slightly pressurized configuration is computed with the aid of finite element interpolation. Based on the stress-strain characteristics, the Ogden model is employed to describe the material behavior. The elastic parameters at every Gauss point in a selected region are identified simultaneously. To verify the predictive capability of the identified material model, the deformation under a prescribed pressure is predicted using the finite element method and is compared with the physical measurement. The experiment shows that the method can effectively delineate the distributive elastic properties in the balloon wall.

Classification of intra-articular distal radial fractures and their arthroscopic reduction and fixation

目前的桡骨远端骨折分类方法有一个共同的缺陷,即没有详细描述关节面的解剖改变.基于CT断层扫描和三维重建技术,根据关节面骨块的数目,日本的土井一辉(Doi)教授将桡骨远端关节内骨折分为3型,即2、3、4块型.此分类法简单但直观准确描述了关节面的结构改变,对关节镜操作非常实用.根据此分类,针对不同的骨折类型,采用腕关节镜辅助下的复位固定,以期达到关节面移位小于1mm的复位和固定效果.1992～2003年,91例桡骨远端关节内骨折患者接受关节镜手术,年龄21～79岁.其中42例为2块型,占46%;34例3块型,占37%;15例4块型,占17%.关节镜用于复位后检查14例,引导克氏针13例,辅助复位固定61例,其中4例改为开放复位内固定.固定方法包括外固定架联合克氏针或钢板、钢板联合拉出钢丝或螺钉,6例单用克氏针,1例单用螺钉.长期的功能随访结果表明,与其它传统方法相比,桡骨远端关节内骨折采用关节镜辅助的复位固定可获得更好的关节活动度和握力.

Predicting spatial activity patterns in a neural map from a probabilistic atlas of 3-D reconstructed neurons

In order to understand how the algorithms underlying neural computation are implemented within any neural system, it is necessary to understand details of the anatomy, physiology and global organization of the neurons from which the system is constructed. Information is represented in neural systems by patterns of activity that vary in both their spatial extent and in the time domain. One of the great challenges to microscopists is to devise methods for imaging these patterns of activity and to correlate them with the underlying neuroanatomy and physiology. We have addressed this problem by using a combination of three dimensional reconstruction techniques, quantitative analysis and computer visualization techniques to build a probabilistic atlas of a neural map in an insect sensory system. The principal goal of this study was to derive a quantitative representation of the map, based on a uniform sample of afferents that was of sufficient size to allow statistically meaningful analyses of the relationships between structure and function.

Computer assisted anatomical reconstruction: a prostate model

We report a computer assisted three dimensional reconstruction technique using serial sections. This reconstruction was achieved by means of a common microcomputer. The organ analyzed in this study was the common European rabbit prostate.

Image Reconstruction Applied to High Voltage Microscopy

Greatly increased specimen penetration, which is the principle advantage of high voltage electron microscopy, carries with it an increased need for techniques to interpret the large amount of three-dimensional information projected into two-dimensional micrographs. Stereo views can provide very useful information and are widely used. However, for the general specimen, stereo views are limited in their ability to produce quantitative results. At the high voltage microscope facility, Univ. of Wisconsin, we have begun a program to develop and apply three dimensional reconstruction techniques to the microscopy of thick specimens.