Three-dimensional reconstruction of human femur using consecutive computer tomography images and simulated implantation system

This study is concerned with the construction of a simulated implantation system (SIS) for a human femur using various algorithms of image processing and computer graphics. The SIS is the software which performs 3D visualization as well as various numeric analyses between the patient's femur and the artificial hip joint through certain stages of processing on consecutive CT images and projected images. We present the concrete methods that were to be implemented into the suggested prototype of SIS and the corresponding experimental results will also be shown.     

Three-dimensional reconstruction and rapid prototyping of femur bone using multiple digital X-rays

The medical industry has made great strides in offering healthcare services, and rapid prototyping (RP) is an example of a tool that has experienced tremendous growth in the medical field. RP technologies are used for building models that provide visual and tactile information. The linking of scanning technology and RP technologies now permit anatomical image data to be viewed in a completely different manner. The feasibility of producing RP models using digital X-rays is explained in this work. Digital X-rays taken at regular angular intervals of the anatomical object are used as input data to reconstruct the anatomical object. Software to detect the edge of the bone projection and export it to two-dimensional coordinates was developed using Visual Basic 6.0. This coordinate data of the image is used for creating the spline of the two-dimensional projections of the bone. Then, using extrusion and Boolean intersection operations, the three-dimensional model of the bone without concavities is reconstructed. In order to incorporate the concavities, a unique method is applied. Using grey-level histograms, the concavities are detected, and using subtraction Boolean operation the concavities are incorporated in the model. The CAD model obtained is converted to stl file format, which is the defacto standard for RP. Using FDM 2000 machine the prototype of the bone is fabricated. The reconstructed model is compared with the CT model of the actual bone. The CT model and X-ray model are compared using the slices taken with a constant inter-slice distance. The fabricated bone model is used as visual-tactile representation, surgical planning and simulation tool for doctors. This would enhance the doctor – patient relationship and reduce the time for surgery.     

Three-dimensional reconstruction and rapid prototyping of femur bone using multiple digital X-rays

The medical industry has made great strides in offering healthcare services, and rapid prototyping (RP) is an example of a tool that has experienced tremendous growth in the medical field. RP technologies are used for building models that provide visual and tactile information. The linking of scanning technology and RP technologies now permit anatomical image data to be viewed in a completely different manner. The feasibility of producing RP models using digital X-rays is explained in this work. Digital X-rays taken at regular angular intervals of the anatomical object are used as input data to reconstruct the anatomical object. Software to detect the edge of the bone projection and export it to two-dimensional coordinates was developed using Visual Basic 6.0. This coordinate data of the image is used for creating the spline of the two-dimensional projections of the bone. Then, using extrusion and Boolean intersection operations, the three-dimensional model of the bone without concavities is reconstructed. In order to incorporate the concavities, a unique method is applied. Using grey-level histograms, the concavities are detected, and using subtraction Boolean operation the concavities are incorporated in the model. The CAD model obtained is converted to stl file format, which is the defacto standard for RP. Using FDM 2000 machine the prototype of the bone is fabricated. The reconstructed model is compared with the CT model of the actual bone. The CT model and X-ray model are compared using the slices taken with a constant inter-slice distance. The fabricated bone model is used as visual-tactile representation, surgical planning and simulation tool for doctors. This would enhance the doctor - patient relationship and reduce the time for surgery.     

Three-dimensional computer reconstruction and display of neuronal structure

Shaded, three-dimensional images of microscopic neuronal structures are generated using a special computer graphics system known as THREAD (Three-Dimensional Reconstruction Aand Display). This system uses both a computer and its associated image processing hard-ware and specialized computer software to produce both line-drawings (contour-grams) and shaded images obtained from 35 mm film negatives of cross-sectional images of microscopic neuronal structures. The resulting image is displayed on a TV monitor in either color or black and white and can be rotated to view all surfaces. Structural volume and planar surface areas are also evaluated during the procedure. Examples of a brainstem region and of a neuron nucleolus are presented.     

双侧股骨近端对称性及解剖形态的三维重建研究

目的建立正常成人双侧股骨近端的三维模型,分析双侧股骨近端形态并测量解剖形态的相关参数,研究双侧股骨近端的对称性及解剖形态。方法选取50例正常成人双侧股骨近端CT扫描数据,其中男性27例,女性23例;年龄20～65岁,平均年龄44.52岁。扫描参数:扫描层厚0.625 mm,扫描电压120 kV,扫描电流100 mA。扫描范围:自双侧股骨头上10 mm至小转子中点平面下50 mm。将双侧股骨近端CT薄层扫描数据利用Mimics 10.01软件进行三维重建,将左侧股骨与右侧股骨镜像模型相配准,对配准后模型进行三维测量,并测量左右股骨近端的形态参数,使用SPSS 16.0软件对测量结果进行统计分析。结果股骨近端形态和髓腔内部结构有明显的个体差异性,双侧股骨近端形态及内部结构具有高度对称性。股骨头直径为(45.71±4.08)mm,股骨头高度为(53.61±5.43)mm,偏心距为(39.91±5.07)mm,股骨颈中央直径为(36.71±3.75)mm,颈干角为(127.88±6.28)°,股骨颈长度(46.61±4.74)mm,小粗隆中点所在平面的髓腔内径为(26.21±4.59)mm,其中偏心距、颈干角与白种人形态参数相比,差异有显著统计学意义(P<0.01);提供了一种验证双侧股骨对称性的新方法。结论正常成人双侧股骨内外部形态存在一定的对称性,变异较小,为股骨形态的测量提供理论依据;三维重建更利于对股骨近端形态参数的测量;新配准方法的提出对于临床中股骨近端骨折的诊治具有重大意义。     

Direct reconstruction of single-photon emission computed tomography images using retained matrix elements

In clinical applications, two methods of single-photon emission computed tomography (SPECT) reconstruction are widely used. These are filtered backprojection and iterative reconstruction. Filtered backprojection is fast and produces acceptable images. Iterative reconstruction is slow, but produces images of greater accuracy than backprojection. The authors sought to develop a method of SPECT reconstruction that would have the advantages of both established methods: close in speed to backprojection and with the accuracy of iterative reconstruction. This was accomplished by computing a direct solution to the set of linear equations governing SPECT reconstruction. We tested this method of SPECT reconstruction using a set of projections from a cold rod and sphere phantom. Direct reconstruction produced images having equivalent resolution to backprojected images, but with double the contrast ratio. The direct method required 10 seconds of computation per slice on a Macintosh Quadra 950 (Apple Computer; Cupertin, CA), significantly faster than most iterative methods.     

三维重建可视化系统可增强下颈椎椎弓根钉置入的准确性

BACKGROUND: Pedicle screw implantation is a common method to repair many kinds of diseases of the lower cervical spine. Three-dimensional (3D) reconstruction visualization system can be used in order to improve the accuracy of the implant and improve the prognosis.     

医学图像的三维重建及基于VTK的实现和应用

背景：VTK是一个免费的图像三维重建和处理的专业开发平台,其功能强大,源代码开放,用户可以根据自己的需求灵活的定制和开发。 目的：介绍图像三维可视化中常用的面绘制和体绘制两类可视化技术的原理,以及其典型的Marching Cubes和Ray Casting三维重建算法,并对重建的三维医学图像的应用和扩展进行了探讨。 方法：基于免费的VTK可视化开发包平台和Visual C++ 6.0 IDE开发工具,使用C++语言,采用真实人体CT数据集,实现CT图像的三维重建和应用扩展。 结果与结论：基于VTK平台,采用面绘制和体绘制不同绘制原理实现了医学图像的三维可视化。重建得到的三维医学图像,显示效果清晰直观,并且可以配合进行三维医学图像的测量、虚拟切割等操作,取得了较好的效果。     

基于CT影像的人体心脏三维重构

三维重构是研究心脏血流机理及特性等问题的有效手段,本文基于CT断层扫描数据,利用Mimics处理工具对心脏进行三维重构,并对左心室优化模型进行偏差分析,优化改变了重构模型的粗糙度,对左心室结构的影响较小为后续探究心脏内部血流模式及特性、血液生理学参数异变和组织结构病变提供了基础研究。     

PC机上基于CT、MRI图像构建的颌面部三维数字模型

背景：近年来国内外学者对个人PC机上重建颌面部骨组织、皮肤、肌肉三维可视化模型进行了大量研究,但对于建立颌面部骨骼、皮肤、肌肉、血管的整体三维可视化模型尚无报道。 目的：利用螺旋 CT、MRI 数据及三维重建软件,在普通 PC 机建立颌面部整体的三维可视化模型。 方法：选择1名健康成年男性作为建模对象,分别通过螺旋CT、核磁共振扫描,得到样本的DICOM标准图像。将所有CT、MRI图像导入Mimics,建立颌面部骨骼、部分咀嚼肌、三叉神经池、颈内动脉、颈内静脉的三维可视化模型。选择颌面部骨骼三维模型为基准,将由MRI图像建立的肌肉、血管、三叉神经池模型导入,进行三维模型空间配准。最终得到颌面部整体的三维可视化模型。 结果与结论：成功建立了颌面部骨骼、肌肉、皮肤、三叉神经池、血管的整体三维模型,准确反映了颌面部复杂的解剖结构,可为临床诊断提供可靠的解剖资料,并为今后的模拟手术打下良好的基础。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程全文链接：     

Three-dimensional imaging and osteometry of adult human skulls using helical computed tomography

To make a digital image database of human craniology, we optimized the three-dimensional (3-D) images of 29 dried human skull specimens by helical computed tomography (CT). For the verification of the quantitative exactitude of these image data, we manually measured nine items of direct distances between standard anthropologic points on each skull and the corresponding distances projected on the CT monitor by specifying the respective points. The results obtained by the two methods of manual and CT measurements were compared and statistically analyzed. The CT measurements were so exact that the lower limit of correlation coefficients (95% of the confidence interval) between the two results was more than 0.8 in six items; i.e., maximal cranial length and breadth, minimal frontal breadth, bizygomatic breadth, distance between ectomolares and nasion-basion length. In contrast, the CT results were less well correlated with the manual measurements of three items; i.e., distance between bilateral mastoidales, total facial height, and nasal breadth. We concluded that the qualitative representation of 3-D CT images was adequate, although some quantitative data may be incorrect. The inaccuracy is suspected to be due to the difficulty in specifying the standard points on the CT images, and due to the differences in measurement procedures between the direct and projected distances.     

Three-dimensional finite-element-based photoacoustic tomography: reconstruction algorithm and simulations

In this paper, a finite element reconstruction algorithm for three-dimensional photoacoustic tomography is described. The algorithm is based on rigorous iterative solution to the Helmholtz photoacoustic wave equation coupled with regularization techniques and is able to recover both the images of absorbed optical energy density and acoustic speed simultaneously. The algorithm is tested using various numerical examples that mimic cancer detection and joint imaging. The results show that the algorithm is able to reconstruct photoacoustic images quantitatively in terms of the location, size, optical and acoustic properties of the target, and background media for various examples examined.     

Receiver operating characteristic and location analysis of simulated near-infrared tomography images

Receiver operating characteristic (ROC) analysis was performed on simulated near-infrared tomography images, using both human observer and contrast-to-noise ratio (CNR) computational assessment, for application in breast cancer imaging. In the analysis, a nonparametric approach was applied for estimating the ROC curves. Human observer detection of objects had superior capability to localize the presence of heterogeneities when the objects were small with high contrast, with a minimum detectable threshold of CNR near 3.0 to 3.3 in the images. Human observers were able to detect heterogeneities in the images below a size limit of 4 mm, yet could not accurately find the location of these objects when they were below 10 mm diameter. For large objects, the lower limit of a detectable contrast limit was near 10% increase relative to the background. The results also indicate that iterations of the nonlinear reconstruction algorithm beyond 4 did not significantly improve the human detection ability, and degraded the overall localization ability for the objects in the image, predominantly by increasing the noise in the background. Interobserver variance performance in detecting objects in these images was low, suggesting that because of the low spatial resolution, detection tasks with NIR tomography is likely consistent between human observers.     

Three-dimensional fluorescence-enhanced optical tomography using a hand-held probe based imaging system

Hand-held based optical imaging systems are a recent development towards diagnostic imaging of breast cancer. To date, all the hand-held based optical imagers are used to perform only surface mapping and target localization, but are not capable of demonstrating tomographic imaging. Herein, a novel hand-held probe based optical imager is developed towards three-dimensional (3-D) optical tomography studies. The unique features of this optical imager, which primarily consists of a hand-held probe and an intensified charge coupled device detector, are its ability to; (i) image large tissue areas (5 x 10 sq. cm) in a single scan, (ii) perform simultaneous multiple point illumination and collection, thus reducing the overall imaging time; and (iii) adapt to varying tissue curvatures, from a flexible probe head design. Experimental studies are performed in the frequency domain on large slab phantoms (approximately 650 ml) using fluorescence target(s) under perfect uptake (1:0) contrast ratios, and varying target depths (1-2 cm) and X-Y locations. The effect of implementing simultaneous over sequential multiple point illumination towards 3-D tomography is experimentally demonstrated. The feasibility of 3-D optical tomography studies has been demonstrated for the first time using a hand-held based optical imager. Preliminary fluorescence-enhanced optical tomography studies are able to reconstruct 0.45 ml target(s) located at different target depths (1-2 cm). However, the depth recovery was limited as the actual target depth increased, since only reflectance measurements were acquired. Extensive tomography studies are currently carried out to determine the resolution and performance limits of the imager on flat and curved phantoms.     

Neural network reconstruction of single-photon emission computed tomography images

An artificial neural network (ANN) trained on high-quality medical tomograms or phantom images may be able to learn the planar data-to-tomographic image relationship with very high precision. As a result, a properly trained ANN can produce comparably accurate image reconstruction without the high computational cost inherent in some traditional reconstruction techniques. We have previously shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, we present a method of deriving activation functions for a backpropagation ANN that make it readily trainable for full SPECT image reconstruction. The activation functions used for this work are based on the estimated probability density functions (PDFs) of the ANN training set data. The statistically tailored ANN and the standard sigmoidal backpropagation ANN methods are compared both in terms of their trainability and generalization ability. The results presented show that a statistically tailored ANN can reconstruct novel tomographic images of a quality comparable with that of the images used to train the network. Ultimately, an adequately trained ANN should be able to properly compensate for physical photon transport effects, background noise, and artifacts while reconstructing the tomographic image.     

Three-dimensional reconstruction of cytoskeletons in rat salivary glands using confocal fluorescence microscopy and volume-rendering computer graphics]

A new reconstruction technique for the demonstration of three-dimensional architectural details from biological fluorescent specimens was used to determine the precise spacial organization of F-actin in rat sublingual glands. F-actin was stained with NBD-phallacidin in thick (20-30 microns) frozen sections and observed with a confocal laser scanning microscope to obtain thin (-1 micron) optically sectioned images. A series of optical sections taken successively at different focal levels in steps of 1 micron was then reconstructed with volume-rendering computer graphics. The rendered images viewed from several angles (e.g. top, bottom, sides) clearly revealed the presence of F-actin fluorescence along the hexagonal framework of the junctional complex within the acini and in the cytoplasm of star-shaped myoepithelial cells encircling the acini. The detailed structures and the topographical relations between the junctional complex and myoepithelial cells were more impressively observed when the rendered images were displayed by motion picture. These images are free from any artifacts caused by the mechanical sectioning and revealed well the delicate and complicated profiles of cellular structures that previously have been almost impossible to demonstrate by conventional reconstruction techniques. We expect that the combination of confocal microscopy and volume rendering will permit the dynamic observation of previously unseen phenomena in three dimensions, such as the behavior of biologically active molecules in living cells.     

附睾管三维重建及解剖

目的 以人附睾组织为研究对象,进行附睾管三维重建,明确附睾管解剖学及组织学特点。 方法 对1例人附睾连续组织切片,Leica Aperio AT2数字扫描,Photoshop CC 2018配准,VGStudio MAX V3.0三维立体合成,Materialise Magics V22.0后期修饰。另1例用于电子显微镜观察。结合切片及三维重建,分析附睾管的组织学特点。 结果 获得7 μm厚的横断面人附睾石蜡切片4331张,矢状面切片543张;人附睾管存在明显的区域性分布,附睾头、体和尾部可分别划分为7个、9个和4个亚区,亚区间有组织间隔;不同亚区内附睾管排列无序,但附睾管管径及其上皮结构存在差异,且体、尾部各亚区间为单根附睾管连接。 结论 利用连续组织切片的方法能成功三维重建人附睾管。揭示人附睾管具有明显的空间区域性,不同亚区组织存在差异。     

Progress towards in vitro quantitative imaging of human femur using compound quantitative ultrasonic tomography

The objective of this study is to make cross-sectional ultrasonic quantitative tomography of the diaphysis of long bones. Ultrasonic propagation in bones is affected by the severe mismatch between the acoustic properties of this biological solid and those of the surrounding soft medium, namely, the soft tissues in vivo or water in vitro. Bone imaging is then a nonlinear inverse-scattering problem. In this paper, we showed that in vitro quantitative images of sound velocities in a human femur cross section could be reconstructed by combining ultrasonic reflection tomography (URT), which provides images of the macroscopic structure of the bone, and ultrasonic transmission tomography (UTT), which provides quantitative images of the sound velocity. For the shape, we developed an image-processing tool to extract the external and internal boundaries and cortical thickness measurements. For velocity mapping, we used a wavelet analysis tool adapted to ultrasound, which allowed us to detect precisely the time of flight from the transmitted signals. A brief review of the ultrasonic tomography that we developed using correction algorithms of the wavepaths and compensation procedures are presented. Also shown are the first results of our analyses on models and specimens of long bone using our new iterative quantitative protocol.     

Three-dimensional reconstruction of registered and fused Chinese Visible Human and patient MRI images

Radiological images are commonly used as important tools in medical diagnoses and treatment. Different modalities of medical images provide uniquely different content. Hence, it is natural and desirable to combine different image modalities to obtain additional new information to enhance clinical assessment. However, given the current technology, radiological images are not always sufficiently informative to permit diagnosis and treatment. In order to address this problem, we fused selected portions of the Chinese Visible Human (CVH) dataset with MRI images from a patient. Specifically, we segmented the caudate nucleus, the lentiform nucleus, and the thalamus in the CVH dataset and then registered and fused this dataset with corresponding MRI images using both rigid and nonrigid registration techniques. After rigid and nonrigid registration, the CVH and MRI images largely coincided with each other. The shape, relationship, and position of focal areas and neural structures were clearly displayed. Using volume and surface rendering, these images were three-dimensionally reconstructed to display the neural structures of interest within the brain. These structures can be rotated at will and observed from different angles. Our research indicates that the fusion of CVH and patients' MRI images can enhance the amount of neural information available to physicians and lay a foundation for the clinical use of the CVH dataset.     

A new filtering algorithm for medical magnetic resonance and computer tomography images

Inner views of tubular structures based on computer tomography (CT) and magnetic resonance (MR) data sets may be created by virtual endoscopy. After a preliminary segmentation procedure for selecting the organ to be represented, the virtual endoscopy is a new postprocessing technique using surface or volume rendering of the data sets. In the case of surface rendering, the segmentation is based on a grey level thresholding technique. To avoid artifacts owing to the noise created in the imaging process, and to restore spurious resolution degradations, a robust Wiener filter was applied. This filter working in Fourier space approximates the noise spectrum by a simple function that is proportional to the square root of the signal amplitude. Thus, only points with tiny amplitudes consisting mostly of noise are suppressed. Further artifacts are avoided by the correct selection of the threshold range. Afterwards, the lumen and the inner walls of the tubular structures are well represented and allow one to distinguish between harmless fluctuations and medically significant structures.