Comparison of Cobb Angles Measured Manually,Calculated from 3-D Spinal Reconstruction,and Estimated from Torso Asymmetry

While scoliotic spinal deformity is traditionally measured by the Cobb angle, we seek to estimate scoliosis severity from the torso surface without X-ray radiation. Here, we measured the Cobb angle in three ways: by protractor from postero-anterior X-ray, by computer from a 3-D digitized model of the vertebral body line, and by neural-network estimation from indices of torso surface asymmetry. The estimates of the Cobb angle by computer and by neural network were equally accurate in 153 records from 52 patients (standard deviation of 6° from the Cobb angle, r =0.93 ), showing that torso asymmetry reliably predicted spinal deformity. Further improvements in predictive accuracy may require estimation of other 3-D indices of spinal deformity besides the Cobb angle with its wide measurement variability.     

DR全脊柱摄影技术在脊柱侧弯中的应用与优势

目的:探讨数字化X线摄影(DR)全脊柱摄像技术在脊柱侧弯中的应用和优势。方法:收集2012年2月至2013年6月于本院进行治疗的脊柱侧弯病例88例,应用数字化X线摄影(DR)技术对脊柱由上至下进行正位和侧位的扫描,均进行3次曝光,每两次曝光间隔均为9秒,曝光后通过图像拼接技术将患者脊柱图像进行拼接和重叠,形成全景图像,对全部患者的图像质量进行观察和评估。结果:所有入选病例中有84例患者图像清晰显示了脊柱侧弯的方向和角度、椎体和椎间隙、对称的椎弓根、根间距及对脏器的影响程度。其中1例因运动不合作出现伪影,3例曝光不足。全脊柱图像质量正位优秀率为92.43%,侧位优秀率为85.92%;全脊柱图像拼接正位优秀率为83.44%,侧位优秀率为86.58%。结论:数字化X线摄影(DR)技术应用上方便快捷,患者配合时间较短,图像质量较好,能够满足临床医生进行诊断和治疗,有助于患者预后康复情况的评估,值得在临床诊断中推广应用。     

基于VTK和MFC的医学图像三维重建研究与实现

VTK是医学可视化领域的主流工具,MFC是Windows平台下的应用程序框架。尝试将两者进行结合编程,以实现二维医学图像的三维重建。实现医学图像三维重建的主要方法是面绘制和体绘制。将利用多组医学图像数据进行三维重建研究,其中面绘制用移动立方体法,体绘制用光线投射法、最大密度投影法和合成体绘制法实现。最后比较两种绘制技术的结果并讨论了它们的特点。结果表明,VTK作为一种图像处理和三维可视化工具其功能是十分强大的。     

电子显微三维重构技术发展与前沿

本文对电子显微三维重构技术(也称电镜三维重构,electron microscopy 3D reconstruction)进行简要介绍,并在此基础上对该技术当前研究的发展和前沿进行综述,包括高分辨率电镜三维重构、仪器设备性能突破、自动化数据收集和处理、高性能计算技术应用、二/三维图像处理技术的发展和创新、基于三维重构图的模型计算等方面,最后对电子显微三维重构技术的未来进行了展望。     

基于光学相干层析图像的离体牙三维重建

利用shear-warp算法对离体牙的光学相干层析图像进行三维重建,通过不透明度传递函数的合理设置及光照模型的引入实现牙齿内部组织结构的可视化,便于医生在早期龋齿诊断中定位病变.介绍了shear-warp算法的原理、用于龋齿检测的全光纤光学相干层析成像系统及其二维层析图,以及利用离体牙牙冠的二维层析图重建获得三维结构图.     

3D representation and analysis of enthesis morphology

This comparison of methods for assessing the development of muscle insertion sites, or entheses, suggests that three‐dimensional (3D) quantification of enthesis morphology can produce a picture of habitual muscle use patterns in a past population that is similar to one produced by ordinal scores for describing enthesis morphology. Upper limb skeletal elements (humeri, radii, and ulnae) from a sample of 24 middle‐aged adult males from the Pottery Mound site in New Mexico were analyzed for both fibrous and fibrocartilaginous enthesis development with three different methods: ordinal scores, two‐dimensional (2D) area measurements, and 3D surface areas. The methods were compared using tests for asymmetry and correlations among variables in each quantitative data set. 2D representations of enthesis area did not agree as closely as ordinal scores and 3D surface areas did regarding which entheses were significantly asymmetrical. There was significant correlation between 3D and 2D data, but correlation coefficients were not consistently high. Intraobserver error was also assessed for the 3D method. Cronbach's alpha values fell between 0.68 and 0.73, and error rates for all entheses fell between 10% and 15%. Marginally acceptable intraobserver error and the analytic versatility of 3D images encourage further investigation of using 3D scanning technology for quantifying enthesis development. Am J Phys Anthropol 152:417–424, 2013. © 2013 Wiley Periodicals, Inc.     

3D打印技术在脊柱侧凸矫形术中的应用研究

目的:通过3D打印技术建立患者脊柱的立体实物模型,并探讨其在脊柱侧凸矫形手术中的临床应用价值。方法:2013年9月～2017年8月的15例脊柱侧凸畸形患者,采集患者的薄层CT扫描数据,利用3D打印技术建立实物模型,术前模拟置钉、模拟截骨,完善术前规划,并按照术前计划进行手术。结果:所有患者均按照根据术前3D打印模型制定的手术方案完成手术,术中置钉顺利,置钉准确率为93.6%。所有患者术中、术后无神经、血管、内脏损伤等并发症。结论:3D打印技术为术者提供了更加直观、立体、即时的影像资料,能够完善术前规划,提高置钉准确率,降低手术风险,在脊柱矫形手术中应用前景广泛。     

Influence of tool rotation on 3D surface topography at the nanometric scale

The influence of the tool rotation on the 3D surface topography produced by the nano-cutting process is investigated using molecular dynamics simulations. The least square mean method is utilized to model the evaluation criteria for the surface roughness parameters. The effects of the tool rotation on the cutting force and the chip formation at the nano-metric scale are also evaluated. It is found that the chip formation produced with tool rotation is dominated by the ploughing and the shearing forces. With increase of the adopted rotation velocity, the cutting force is sharply increased and the smaller elastic recovery of the machined surface is observed. The 3D surface roughness parameters at the nano-metric scale are significantly influenced by the tool rotation velocity and the feed speed, and the surface quality can be improved by decreasing the tool rotation velocity and the feed speed.     

Technical note: The use of 3D printing in dental anthropology collections

Objectives

Rapid prototyping (RP) technology is becoming more affordable, faster, and is now capable of building models with a high resolution and accuracy. Due to technological limitations, 3D printing in biological anthropology has been mostly limited to museum displays and forensic reconstructions. In this study, we compared the accuracy of different 3D printers to establish whether RP can be used effectively to reproduce anthropological dental collections, potentially replacing access to oftentimes fragile and irreplaceable original material.

Methods

We digitized specimens from the Yuendumu collection of Australian Aboriginal dental casts using a high‐resolution white‐light scanning system and reproduced them using four different 3D printing technologies: stereolithography (SLA); fused deposition modeling (FDM); binder‐jetting; and material‐jetting. We compared the deviations between the original 3D surface models with 3D print scans using color maps generated from a 3D metric deviation analysis.

Results

The 3D printed models reproduced both the detail and discrete morphology of the scanned dental casts. The results of the metric deviation analysis demonstrate that all 3D print models were accurate, with only a few small areas of high deviations. The material‐jetting and SLA printers were found to perform better than the other two printing machines.

Conclusions

The quality of current commercial 3D printers has reached a good level of accuracy and detail reproduction. However, the costs and printing times limit its application to produce large sample numbers for use in most anthropological studies. Nonetheless, RP offers a viable option to preserve numerically constraint fragile skeletal and dental material in paleoanthropological collections.

     

3D数字打印技术在重度脊柱侧弯中的临床分析研究

目的:评估和比较3D数字打印技术在重度脊柱侧弯患者手术中的临床疗效及安全性。方法:按照已经设定的纳入及排除标准,对2017年1月至2019年1月诊断为重度脊柱侧弯并在我科行手术治疗的22名患者进行前瞻性分析。根据是否采用3D打印技术辅助,将其通过随机数字表分为3D辅助组(实验组)与对照组。实验组(共11例)通过Minics软件进行3D模拟设计及打印,术中进行技术辅助。对照组(11例)则通过常规的徒手置钉办法进行手术。通过CT比较两组患者的置钉准确性,并比较两组患者的其他影像学检查和相关手术指标,包括:手术时间,输血量,透视次数等。结果:本研究纳入的患者(22例)均得到至少6个月的完整随访。两组患者在术前的影像学测评,Cobb角,年龄、性别构成等指标的比较中未见显著统计学差异(P>0.05)。实验组CT评价置钉准确率为83.6%(0级及1级),对照组的置钉准确率为72.3%。两组比较有统计学差异(P<0.05)。实验组在手术时间,术中输血量及透视次数等手术指标的比较中均显著优于对照组(P<0.05)。实验组的入院后待手术时间显著高于对照组(P<0.05)。实验组在术后3天的VAS指标显著优于对照组(P<0.05),但在术后6月的比较中无显著性差异(P>0.05)。两组患者的ODI指数较术前均有显著改善(P<0.05),且两组间无显著性差异(P>0.05)。两组患者均未出现严重并发症(P>0.05)。结论:与常规的徒手置钉相比,针对重度脊柱侧弯患者,3D数字打印辅助技术能够显著的提高置钉的准确性,减少手术时间和术中输血量,大幅度减少透视危害,且降低操作难度,值得临床进一步推广使用。     

基于无人机三维重建现状模型的风景园林设计研究与教学探索

随着无人机技术在风景园林规划设计中发挥越来越重要的作用,将无人机技术引入风景园林设计和教学已经成为可能。本文通过阐述无人机三维重建技术的概念、技术流程和技术优势、该技术在风景园林设计中的应用以及该技术与风景园林设计教学的结合方式,展示了以无人机三维重建现状模型为结合点,风景园林设计、教学与前沿科学技术的融合。     

Customized k-nearest neighbourhood analysis in the management of adolescent idiopathic scoliosis using 3D markerless asymmetry analysis

Adolescent Idiopathic Scoliosis (AIS) is a 3D spinal deformity characterized by curvature and rotation of the spine. Markerless surface topography (ST) analysis has been proposed for diagnosing and monitoring AIS to reduce the X-ray radiation exposure to patients. This method captures scans of the cosmetic deformity of the torso using visible, radiation-free light. The asymmetry analysis of the torso, represented as a deviation contour map with deviation patches outlining the areas of cosmetic asymmetries, has previously been shown to predict the severity and progression of the condition in comparison with radiographs, by using classification trees. While the classification results were promising, it was reported that some mild curves were erroneously diagnosed. Furthermore, this approach is highly sensitive to threshold values selected in the decision trees. Therefore, this study aims to define a custom Neighbourhood Classifier algorithm for AIS classification to improve the accuracy, sensitivity, and specificity of predicting curve severity and curve progression in AIS. Curve severity was predicted with 80% accuracy (sensitivity = 81%; specificity = 79%) for thoracic-thoracolumbar curves and 72% (sensitivity = 93%; specificity = 53%) for lumbar curves. This represents an improvement over the previous method with curve severity accuracies of 77% and 63% for thoracic-thoracolumbar and lumbar curves, respectively. Additionally, curve progression was predicted with 93% accuracy (sensitivity = 83%; specificity = 95%) representing a substantial improvement over the previous method with an accuracy of 59%. The current method has shown the potential to further reduce radiation exposure for AIS patients by avoiding X-rays for mild and non-progressive curves identified using ST analysis.     

Nucleolar apparatus in the macronucleus of Didinium nasutum (Ciliata): EM and 3D reconstruction

The three-dimensional (3D) organization of nucleoli in the somatic nuclei (macronuclei) of recently fed and starved Didinium nasutum was reconstructed on the basis of serial ultra-thin sections. It was shown that nucleoli, looking on the single sections like individual separate structures, appeared to be parts of the large complicated branchy nucleolar networks. A 30 h starvation did not lead to disintegration of this network, but stimulated formation of numerous vacuoles in the granular component of nucleoli, which becomes more condensed. Unlike starved D. nasutum, in fed ciliates numerous holes appeared in the fibrillar component located at the periphery of nucleoli. These holes may presumably serve as channels for transporting newly synthesized rRNA. To our knowledge, this is the first report of a 3D reconstruction of the nucleolar apparatus in ciliates.     

3D immuno-confocal image reconstruction of fibroblast cytoskeleton and nucleus architecture

Computational models of cellular structures generally rely on simplifying approximations and assumptions that limit biological accuracy. This study presents a comprehensive image processing pipeline for creating unified three-dimensional (3D) reconstructions of the cell cytoskeletal networks and nuclei. Confocal image stacks of these cellular structures were reconstructed to 3D isosurfaces (Imaris), then tessellations were simplified to reduce the number of elements in initial meshes by applying quadric edge collapse decimation with preserved topology boundaries (MeshLab). Geometries were remeshed to ensure uniformity (Instant Meshes) and the resulting 3D meshes exported (ABAQUS) for downstream application. The protocol has been applied successfully to fibroblast cytoskeletal reorganisation in the scleral connective tissue of the eye, under mechanical load that mimics internal eye pressure. While the method herein is specifically employed to reconstruct immunofluorescent confocal imaging data, it is also more widely applicable to other biological imaging modalities where accurate 3D cell structures are required.     

Investigation of 3D glenohumeral displacements from 3D reconstruction using biplane X-ray images: Accuracy and reproducibility of the technique and preliminary analysis in rotator cuff tear patients

Rotator cuff (RC) tears may be associated with increased glenohumeral instability; however, this instability is difficult to quantify using currently available diagnostic tools. Recently, the three-dimensional (3D) reconstruction and registration method of the scapula and humeral head, based on sequences of low-dose biplane X-ray images, has been proposed for glenohumeral displacement assessment. This research aimed to evaluate the accuracy and reproducibility of this technique and to investigate its potential with a preliminary application comparing RC tear patients and asymptomatic volunteers. Accuracy was assessed using CT scan model registration on biplane X-ray images for five cadaveric shoulder specimens and showed differences ranging from 0.6 to 1.4 mm depending on the direction of interest. Intra- and interobserver reproducibility was assessed through two operators who repeated the reconstruction of five subjects three times, allowing defining 95% confidence interval ranging from ±1.8 to ±3.6 mm. Intraclass correlation coefficient varied between 0.84 and 0.98. Comparison between RC tear patients and asymptomatic volunteers showed differences of glenohumeral displacements, especially in the superoinferior direction when shoulder was abducted at 20° and 45°. This study thus assessed the accuracy of the low-dose 3D biplane X-ray reconstruction technique for glenohumeral displacement assessment and showed potential in biomechanical and clinical research.     

螺旋CT扫描及三维重建技术在股骨颈骨折分型及治疗中的应用

目的:探讨螺旋CT扫描及三维重建技术在股骨颈骨折分型及治疗中的应用价值。方法:选择2010年5月~2013年5月期间我院收治的股骨颈骨折患者237例为研究对象,根据患者扫描检查方式的不同将其分为对照组(112例)和观察组(125例),对照组患者行髋关节X线正位扫描,观察组行髋关节正位64排螺旋CT扫描,两组均根据扫描结果进行分型并制定相应的治疗方案,比较两组患者骨折内固定手术后2年的股骨头坏死率及骨折不愈合率。结果:两组行骨折内固定手术比例比较,差异无统计学意义(P0.05);术后2年,对照组股骨头坏死5例(22.73%),骨不连6例(27.27%);观察组股骨头坏死1例(3.70%),骨不连1例(3.70%),观察组患者股骨头坏死率及骨折不愈合率均显著低于对照组,差异均有统计学意义(P0.05)。结论:螺旋CT扫描及三维重建成像能够全面、准确显示股骨颈骨折的损伤情况,有助于骨折的正确分型和治疗方法的选择,改善预后。     

Contributions of pro-oxidant and anti-oxidant conditions to the actions of 24,25-dihydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 on phosphate uptake in intestinal cells

The steroid hormone 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] rapidly stimulates the uptake of phosphate in isolated chick intestinal cells, while the steroid 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] inhibits the rapid stimulation by 1,25(OH)2D3. Earlier work in this laboratory has indicated that a cellular binding protein for 24,25(OH)2D3 is the enzyme catalase. Since binding resulted in decreased catalase activity and increased H2O2 production, studies were undertaken to determine if pro-oxidant conditions mimicked the inhibitory actions of 24,25(OH)2D3, and anti-oxidant conditions prevented the inhibitory actions of 24,25(OH)2D3. An antibody against the 24,25(OH)2D3 binding protein was found to neutralize the inhibitory effect of the steroid on 1,25(OH)2D3-mediated 32P uptake. Incubation of cells in the presence of 50 nM catalase was also found to alleviate inhibition. In another series of experiments, isolated intestinal epithelial cells were incubated as controls or with 1,25(OH)2D3, each in the presence of the catalase inhibitor 3-amino-1,2,4-triazole, or with 1,25(OH)2D3 alone. Cells exposed to hormone alone again showed an increased accumulation of 32P, while cells treated with catalase inhibitor and hormone had uptake levels that were indistinguishable from controls. We tested whether inactivation of protein kinase C (PKC), the signaling pathway for 32P uptake, occurred. Incubation of cells with phorbol-13-myristate (PMA) increased 32P uptake, while cells pretreated with 50 microM H2O2 prior to PMA did not exhibit increased uptake. Likewise, PMA significantly increased PKC activity while cells exposed to H2O2 prior to PMA did not. It is concluded that catalase has a central role in mediating rapid responses to steroid hormones.     

Estrogen-induced cyclin D1 and D3 gene expressions during mouse uterine cell proliferation in vivo: Differential induction mechanism of cyclin D1 and D3

D-type cyclins are involved in the regulation of the G₁/S transition of the cell cycle in various cell types cultured in vitro. Little is, however, known about the expression pattern and functional role of D-type cyclins in physiological processes in vivo. In this report, we studied whether the expression of murine D-type cyclins correlates with the states of mouse uterine cell proliferation in vivo. Time-course changes in cyclin D1 and D3 mRNA levels in the uterine tissues of immature mice primed with 17β-estradiol (E₂) were examined by Northern blot hybridization. c-fos and thymidine kinase (TK) mRNA levels were also examined as markers for the transition from G₀ to G₁ and the onset of S phase, respectively. Cyclin D1 and D3 mRNAs were induced 2.5-fold between c-fos and TK mRNA peaks. The E₂-induced cyclin D1 and D3 gene expressions were blocked by antiestrogens tamoxifen and ICI 182,780. We also investigated the effects of cycloheximide (CHX), a protein synthesis inhibitor, on cyclin D1 and D3 gene expressions. When CHX was treated alone, cyclin D3, but not cyclin D1, mRNA was immediately superinduced. The E₂-induced cyclin D3 gene expression was shifted by approximately 6 h when CHX was pretreated 1 hr before E₂ administration. Interestingly, the ³H-thymidine incorporation experiment showed that the mouse uterine cell cycle progression also shifted by 6 hr with pretreatment of CHX. The overall results suggest that both cyclin D1 and D3 mRNAs are constitutively expressed in uterine tissues and induced by E₂ at G₁ phase of the mouse uterine cell cycle. However, the superinducibility and temporal shift of cyclin D3 by CHX suggest that there is a different regulatory mechanism underlying cyclin D1 and D3 gene expressions in the mouse uterine cell cycle progression. Mol. Reprod. Dev. 46:450–458, 1997. © 1997 Wiley-Liss, Inc.     

Identification of Dopamine "D3'' and "D4'' Binding Sites, Labelled with [3H]2-Amino-6,7-Dihydroxy- 1,2,3,4- Tetrahydronaphthalene, as High Agonist Affinity States of the D1 and D2 Dopamine Receptors, Respectively

On the basis of affinity differences for spiperone, two binding sites for [3H](+/-)-2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene ([3H]ADTN) in the rat brain could be distinguished: "D3" with a low and "D4" with a high affinity for spiperone. Evidence is provided that D3 and D4 sites are related to high agonist affinity states of the D1 and D2 dopamine receptors, respectively. Various well-known selective D1 and D2 agonists and antagonists showed potencies at these sites in agreement with this hypothesis. A comparison of the Bmax values for [3H]ADTN binding to D3 and D4 sites with the numbers of D1 receptors (labelled by [3H]SCH 23390) and of D2 receptors (labelled by [3H]spiperone), both in the striatum and in the mesolimbic system, indicated that under the conditions used for 3H-agonist binding experiments, both populations of D1 and D2 receptors were converted to their high agonist affinity states to a considerable, although different extent. In fact, when competition experiments with [3H]spiperone were performed under the conditions otherwise used for [3H]ADTN binding experiments (instead of the conditions usually used for antagonist binding), substantial shifts of the displacement curves of 3,4-dihydroxyphenylethylamine (dopamine) and ADTN toward higher affinities were observed. A comparison of the effects of various agonists and antagonists in the [3H]ADTN binding experiments and in functional tests revealed a significant correlation between their potencies at D4 binding sites and at D2 receptors modulating the release of [3H]acetylcholine from striatal slices. However, in the situation of the D1/D3 pair, when the measurement of adenylate cyclase activity was taken as a functional test for D1 receptors, agonists were more active in the binding than in the functional test, whereas for many antagonists the opposite was found. The results are discussed with regard to the classification and functional aspects of brain dopamine receptors.