Using on-site liver 3-D reconstruction and volumetric calculations in split liver transplantation

BACKGROUND： Split liver transplantation increases the number of grafts available for transplantation. Pre-recovery assessment of liver graft volume is essential for selecting suitable recipients. The purpose of this study was to determine the ability and feasibility of constructing a 3-D model to aid in surgical planning and to predict graft weight prior to an in situ division of the donor liver. METHODS： Over 11 months, 3-D volumetric reconstruction of 4 deceased donors was performed using Pathfinder Scout liver volumetric software. Demographic, laboratory, operative, perioperative and survival data for these patients along with donor demographic data were collected prospectively and analyzed retrospectively. RESULTS： The average predicted weight of the grafts from the adult donors obtained from an in situ split procedure were 1130 g （930-1458 g） for the extended right lobe donors and 312 g （222-396 g） for left lateral segment grafts. Actual adult graft weight was 92% of the predicted weight for both the extended right grafts and the left lateral segment grafts. The predicted and actual graft weights for the pediatric donors were 176 g and 210 g for the left lateral segment grafts and 308 g and 280 g for the extended right lobe grafts,respectively. All grafts were transplanted except for the right lobe from the pediatric donors due to the small graft weight.CONCLUSIONS： On-site volumetric assessment of donors provides useful information for the planning of an in situ split and for selection of recipients. This information may expand the donor pool to recipients previously felt to be unsuitable due to donor and/or recipient weight.

Parallel computing approach for efficient 3-D X-ray-simulated image reconstruction

Accurate 3-dimensional(3-D)reconstruction technology for nondestructive testing based on digital radiography(DR)is of great importance for alleviating the drawbacks of the existing computed tomography(CT)-based method.The commonly used Monte Carlo simulation method ensures well-performing imaging results for DR.However,for 3-D reconstruction,it is limited by its high time consumption.To solve this problem,this study proposes a parallel computing method to accelerate Monte Carlo simulation for projection images with a parallel interface and a specific DR application.The images are utilized for 3-D reconstruction of the test model.We verify the accuracy of parallel computing for DR and evaluate the performance of two parallel computing modes-multithreaded applications(G4-MT)and message-passing interfaces(G4-MPI)-by assessing parallel speedup and efficiency.This study explores the scalability of the hybrid G4-MPI and G4-MT modes.The results show that the two parallel computing modes can significantly reduce the Monte Carlo simulation time because the parallel speedup increment of Monte Carlo simulations can be considered linear growth,and the parallel efficiency is maintained at a high level.The hybrid mode has strong scalability,as the overall run time of the 180 simulations using 320 threads is 15.35 h with 10 billion particles emitted,and the parallel speedup can be up to 151.36.The 3-D reconstruction of the model is achieved based on the filtered back projection(FBP)algorithm using 180 projection images obtained with the hybrid G4-MPI and G4-MT.The quality of the reconstructed sliced images is satisfactory because the images can reflect the internal structure of the test model.This method is applied to a complex model,and the quality of the reconstructed images is evaluated.

Preoperative 3D reconstruction and fluorescent indocyanine green for laparoscopic duodenum preserving pancreatic head resection:A case report

BACKGROUND Duodenum-preserving pancreatic head resection(DPPHR)is the choice of surgery for benign or low-grade malignant tumors of the pancreatic head.Laparoscopic DPPHR(LDPPHR)procedure can be improved by preoperative 3D model reconstruction and the use of intravenous indocyanine green fluorescent before surgery for real-time navigation with fluorescent display to guide the surgical dissection and prevention of from injury to vessels and biliary tract.CASE SUMMARY Here we report the successful short-and long-term outcomes after one year following LDPPHR for a 60-year lady who had an uneventful recovery and was discharged home one week after the surgery.CONCLUSION There was no bile leakage or pancreatic leakage or delayed gastric emptying.The histopathology report showed multiple cysts in the pancreatic head and localized pancreatic intraepithelial tumor lesions.The resected margin was free of tumor.

A 3-D RECONSTRUCTION METHOD BASED ON THE CONSTRAINT OF EPIPOLAR GEOMETRY

This paper combines the least-square method and iteration method to get the fundamental matrix and develops a new evaluation function based on the epipolar geometry. During the iteration, with the evaluation function as a measurment, the points which bring larger noise are deleted, and the points with smaller noise are retained, thus the precision of our method is increased. The experiment results indicate the new method is precise in calculation, stable in performance and resistant to noise.

3-D Reconstruction and Visualization of Laser-Scanned Trees by Weighted Locally Optimal Projection and Accurate Modeling Method

This paper presents a method to reconstruct 3-D models of trees from terrestrial laser scan(TLS)point clouds.This method uses the weighted locally optimal projection(WLOP)and the AdTree method to reconstruct detailed 3-D tree models.To improve its representation accuracy,the WLOP algorithm is introduced to consolidate the point cloud.Its reconstruction accuracy is tested using a dataset of ten trees,and the one-sided Hausdorff distances between the input point clouds and the resulting 3-D models are measured.The experimental results show that the optimal projection modeling method has an average one-sided Hausdorff distance(mean)lower by 30.74%and 6.43%compared with AdTree and AdQSM methods,respectively.Furthermore,it has an average one-sided Hausdorff distance(RMS)lower by 29.95%and 12.28%compared with AdTree and AdQSM methods.Results show that the 3-D model generated fits closely to the input point cloud data and ensures a high geometrical accuracy.

Reconstruction of Temperature Field in 3-D, Absorbing, Emitting, and Anisotropically Scattering Medium

The soft measurement technology of flame temperature field is an efficient method to learn the combustion status in furnace. Generally, it reconstructs the temperature field in furnace through the image of flame, which is a process to solve radiative inverse problem. In this paper, the flame of pulverized coal is considered as 3-D, absorbing, emitting, and anisotropically scattering non-gray medium. Through the study on inverse problem of radiative heat transfer, the temperature field in this kind of medium has been reconstructed. The mechanism of 3-D radiative heat transfer in a rectangular media, which is 2 m×3 m× 5 m and full of CO2, N2 and carbon particles, is studied with Monte Carlo method. The 3-D temperature field in this rectangular space is reconstructed and the influence of particles density profile is discussed.

An Experimental System Development for Head Posture Estimation Based on 3-D Images Measurement

Although automobile is an indispensable vehicle to modern life, it also serves as a social problem with a big traffic accident. Among the reasons of traffic accidents, careless driving accounts for the largest part. So in order to avoid the careless driving, a system which can measure the posture of a driver and warns driver to drive carefully in the case of looking aside is necessary. Although the image measurement method is used broadly, there is a problem on which measurement accuracy is influenced by environment light, makeup of the driver, etc. in the general method based on the two-dimensional image. Therefore, in this study, we propose an image measurement method to obtain the head posture of driver. First we use three-dimensional measurement method which based on the infrared pattern projection to get 3-D information of head, and then we calculate the angle for faces. In this paper, we explain the composition method of an experiment system, and the results of head posture measurement experiment.

PC-BASED SURFACE RECONSTRUCTION OF MEDICAL CT IMAGES

It is an active research area to reconstruct 3-D object and display its visible surfacesfrom cross-sectional images. In this paper, the methods of reconstructing 3-D object from medicalCT images and displaying the visible surfaces are discussed. A polygon approximation methodthat forms polygon with the same number of segment points and a fast interpolation method forcross-sectional contours are presented at first. Then the voxel set of a human liver is reconstructed.And then the liver voxel set is displayed using depth and gradient shading methods. The softwareis written in C programming language at a microcomputer image processing system with a PC/ATcomputer as the host and a PC-VISION board as the image processing unit. The result of theprocessing is satisfying.

A new navigation approach of terrain contour matching based on 3-D terrain reconstruction from onboard image sequence

This article presents a passive navigation method of terrain contour matching by reconstructing the 3-D terrain from the image sequence(acquired by the onboard camera).To achieve automation and simultaneity of the image sequence processing for navigation,a correspondence registration method based on control points tracking is proposed which tracks the sparse control points through the whole image sequence and uses them as correspondence in the relation geometry solution.Besides,a key frame selection method based on the images overlapping ratio and intersecting angles is explored,thereafter the requirement for the camera system configuration is provided.The proposed method also includes an optimal local homography estimating algorithm according to the control points,which helps correctly predict points to be matched and their speed corresponding.Consequently,the real-time 3-D terrain of the trajectory thus reconstructed is matched with the referenced terrain map,and the result of which provides navigating information.The digital simulation experiment and the real image based experiment have verified the proposed method.

RM-CSTV:An effective high-resolution method of non-line-of-sight millimeter-wave radar 3-D imaging

Non-line-of-sight(NLOS)imaging is a novel radar sensing technology that enables the reconstruction of hidden targets.However,it may suffer from synthetic aperture length reduction caused by ambient occlusion.In this study,a complex total variation(CTV)regularization-based sparse reconstruction method for NLOS three-dimensional(3-D)imaging by millimeter-wave(mm W)radar,named RM-CSTV method,is proposed to improve imaging quality and speed.In this scheme,the NLOS imaging model is first introduced,and associated geometric constraints for NLOS objects are established.Second,an effective high-resolution NLOS imaging method based on the range migration(RM)kernel and complex sparse joint total variation constraint,dubbed as modified RM-CSTV,is proposed for 3-D high-resolution imaging with edge information.The experiments with multi-type NLOS targets show that the proposed RM-CSTV method can provide effective and high-resolution NLOS targets 3-D imaging.

Three-Dimensional Reconstruction of E.coli SecA at Low Resolution

SecA is the essential component of the signal-peptide dependent translocation pathway in Escherichia coil （E.coh）. The structure and function of SecA must be known to understand the molecular mechanism of preprotein translocation. The high flexibility of SecA causes a dynamic conformational heterogeneity which presents a barrier to the growth of crystals of high diffraction quality. Electron microscopy was used to resolve the macromolecular structure of SecA in solution by negative staining and single particle analysis at a resolution of 2.9 nm. The structure of E. coil SecA is similar to the dimeric form of Bacillus subtilis SecA and is 10 nm × 10 nm × 5 nm in size.

首例中国可视化人体头颈部CT影像三维重建的初步研究

目的 对首例中国可视化人体头颈部CT影像进行三维重建研究。方法 将首例中国可视化人体头颈部的轴位断层CT图像 (层厚 1mm ,连续扫描 ) ,应用SiemensCRT3 .0图像处理软件在SGIGraphics计算机工作站上进行三维重建和观察。结果 头面部结构得到良好重建 ,其面部轮廓包括鼻翼、唇、外耳廓、下颏等均能清晰显示。头颈部骨骼的精细三维重建 ,显示出颅底圆孔、卵圆孔、棘孔等细微结构。头颈部三维剖面观察可使包括垂体、脑干、颈髓、蝶窦、鼻咽等结构获得良好显示。结论 本研究实现了对首例中国可视化人体头颈部CT影像的三维重建和可视化 。

基于CT数据的Mimics重建技术在THA患者术后早期全髋界面骨密度分析中的应用

目的采用Mimics重建技术观察生物型全髋关节置换术(THA)患者术后早期全髋界面骨密度(BMD)变化。方法选择股骨头缺血性坏死患者20例,均采用生物型假体行THA。患者手术前及术后1、3、6、12个月行髋关节64排螺旋CT检查,采集CT断层数据。将CT断层数据导入Mimics软件进行髋关节三维模型重建,设定模型基点,采用其自带的CAD工具将股骨头-髋臼弧形界面分为10等份,分别标记为A^J共10个区域,测量每个区域的平均CT值,表示其BMD。结果 20例THA患者术前及术后各时间点A、B、C、D区域BMD比较差异均无统计学意义(P均>0.05);患者术后3、6、12个月E、F、G区域BMD均高于术前,I、J区域BMD均低于术前(P<0.05或<0.01);患者术后1、3、6、12个月H区域BMD均低于术前(P<0.05或<0.01)。结论生物型THA患者手术前后髋臼假体上极周围BMD变化不大,而随着术后时间的延长,中心部位BMD逐渐升高,下极周围BMD逐渐降低。

基于正交图像的头部三维模型构建

为快速构建人体头部的三维模型,提出了一种使用头部正面和侧面两张正交图像进行重建的方法.首先,利用Candide-3模型生成标准头部模型;然后,利用改进的主动形状模型(ASM)自动获取正面图像中68个特征点和侧面图像中35个特征点,并将获取的特征点与标准头部模型中的顶点进行匹配,利用匹配特征点对标准模型进行全局变形和局部变形,从而获得个性化模型;最后,对侧面头像进行仿射变换,使之与正面图像配准,并通过柱面投影和加权融合获得人脸全景纹理图,将其映射到个性化模型上以获得逼真的头部模型.实验结果表明:与传统ASM算法相比,利用改进ASM算法获得的特征点定位准确度提高了13.1%;所提方法仅需约1.2 s便可重建出具有真实感的头部三维模型,并能提供较大范围的可视角度和较丰富的深度信息.

三维重建技术在辅助胰头癌手术治疗中的应用

目的探讨三维重建技术在辅助胰头癌手术治疗中的应用价值。方法回顾性分析2019年5月至2021年9月福建省立医院收治并以三维重建技术辅助手术治疗的14例胰头癌患者的临床资料。采集术前CT/MRI增强扫描的影像资料,通过IQQA-3D系统完成三维可视化重建,进行三维可视化可切除性分型、肝动脉变异分型,并与术中情况进行比较。结果14例患者中,可切除性评估为Ⅰ型7例,Ⅱ型5例,Ⅲ型2例。主要术式为胰十二指肠切除术12例,加行门静脉部分切除重建2例。肝动脉变异4例,术中所见与重建影像相符。结论三维重建技术有助于对胰头肿瘤和周围重要结构空间关系的评估及对重要血管变异的预判,在辅助胰头癌手术治疗方面具有良好的应用前景。

都江堰渠首工程改造对岷江中下游径流过程的影响分析

都江堰于1974年修建了外江枢纽闸以自主调节内外江分水,其在满足自然行洪的同时,不可避免地对下游水资源利用以及下游水环境产生影响。为探究都江堰渠首工程改造对岷江中下游径流过程的影响,通过回顾都江堰渠首工程的历史演化,利用已有水文资料分析都江堰渠首工程改造前后岷江及内江、外江的径流过程影响。研究发现:渠首改造前,内江汛期流量波动较大,改造后内江汛期7月流量由348m^(3)/s增至396m^(3)/s,枯期1月则由133m^(3)/s降低为120m^(3)/s,全年平均径流量由215m^(3)/s增加至245m^(3)/s;渠首改造前后,岷江汛期流量变化不大,流量波动很大,枯期流量略有减小,岷江彭山站全年平均径流量由704m^(3)/s,减小为676m^(3)/s;渠首改造前后,岷江外江汛期与枯期流量均有所减小,外江全年平均流量由384m^(3)/s减小为322m^(3)/s。

Virtual Temporal Bone Anatomy

Background The Visible Human Project(VHP) initiated by the U.S. National Library of Medicine has drawn much attention and interests from around the world. The Visible Chinese Human(VCH) project has started in China. The current study aims at acquiring a feasible virtual methodology for reconstructing the temporal bone of the Chinese population, which may provide an accurate 3-D model of important temporal bone structures that can be used in teaching and patient care for medical scientists and clinicians. Methods A series of sectional images of the temporal bone were generated from section slices of a female cadaver head. On each sectional image, SOIs (structures of interest) were segmented by carefully defining their contours and filling their areas with certain gray scale values. The processed volume data were then inducted into the 3D Slicer software(developed by the Surgical Planning Lab at Brigham and Women’s Hospital and the MIT AI Lab) for resegmentation and generation of a set of tagged images of the SOIs. 3D surface models of SOIs were then reconstructed from these images. Results The temporal bone and structures in the temporal bone, including the tympanic cavity, mastoid cells, sigmoid sinus and internal carotid artery, were successfully reconstructed. The orientation of and spatial relationship among these structures were easily visualized in the reconstructed surface models. Conclusion The 3D Slicer software can be used for 3- dimensional visualization of anatomic structures in the temporal bone, which will greatly facilitate the advance of knowledge and techniques critical for studying and treating disorders involving the temporal bone.

Review of cost and surgical time implications using virtual patient specific planning and patient specific implants in midface reconstruction

Aim:Summarize the available data on midfacial virtual patient specific planning and patient specific implants,highlighting the financial costs and savings,and additionally emphasize the potential cost implications of transitioning to“in-house”virtual 3D modeling and printing.Methods:Review of current literature.Results:Current literature suggests cost benefits of virtual patient specific planning and patient specific implants in the form of improved ischemia time,better boney apposition between flaps,and reduced patient complications.This reduction of complications includes a reduction in blood loss and time spent in the intensive care unit from flap failure.Improved boney apposition results in a higher likelihood of boney union and a further reduction in failure and complications.Subjective benefits of virtual patient specific planning and patient specific implants are shown in the form of improved reconstructive surgeon mental energy.In-house production of 3D models and presurgical planning provides additional cost benefits for providers as they can produce viable models at a fraction of the price of that which is produced by industrial companies.Providers can also construct and use models in an expedient manner compared to industrial models,allowing for the opportunity to be utilized in more acute settings.The foundation of developing an in-house workflow is adequate funding,resources,and clinical volume.Facilities also must focus on appropriate quality and safety measures,as well as appropriate workflow development for adequate production of models.Conclusion:Virtual patient specific planning and patient specific implants show benefits in midfacial reconstructive outcomes,resulting in realized financial and temporal gains for both patient and provider.These gains may be enhanced by moving to in-house planning and printing.

三维重建和体积测量法预测股骨头坏死的塌陷

目前尚没有统一的确定股骨头坏死病灶的大小和部位的方法,导致对股骨头坏死的治疗方案存在争议。该文利用三维重建技术对坏死股骨头的M R I影像进行重构,获得坏死股骨头的三维几何模型,并由几何模型测量得到股骨头及坏死病灶的体积,同时进行临床实验获得真实坏死股骨头的体积数据。通过对38髋病人股骨头的计算机几何模型数据与临床实验数据的统计分析,讨论了股骨头坏死病灶大小和部位与股骨头塌陷的关系。结果表明,该方法可用于指导选择最佳的临床治疗方案。

基于真实感三维头重建的人脸替换

传统的人脸替换技术需要输入的源图像中的人脸与待替换的目标图像中的人脸姿态相似,这限制了人脸替换技术的应用。该文提出一种基于特定三维头模型重建的人脸替换技术。首先,利用替换者的2张正交图像(1张正面图像和1张侧面图像)进行三维头重建。整个三维头重建过程分为人脸图像配准、特征点匹配、标准三维头形变和纹理贴图4个部分。形变部分利用了径向基函数对标准三维头进行形变以获得最终的特定三维头模型。通过建立替换者的真实感三维头模型,渲染出与任意目标图像姿态相一致的人脸图像。为了让渲染后的人脸图像与目标图像进行无缝纹理融合,还进行了色彩传递和基于多分辨率技术的边界融合。用此方法可将故事书中的任意角色替换成用户,以此提供个性化的图书。