双源CT三维重建前交叉韧带移植物新技术

目的:探讨双源CT(DSCT)三维重建前交叉韧带(anterior cruciate ligament,ACL)重建术后移植物的技术方法。方法:对30例ACL损伤后移植重建术后患者进行DSCT扫描,利用软件三维重建ACL移植物的三维图像,对图像效果进行分析。结果:采用设定的参数和方法,30例患者的ACL移植物均获得三维重现,其中24例获得清晰的移植物图像,6例移植物图像略模糊。结论:DSCT可以重建出移植术后ACL移植物的三维图像,对临床检验、评估重建技术、修正重建方法、实现解剖重建有重大价值。     

A probable case of Hand-Schueller-Christian's disease in an Egyptian mummy revealed by CT and MR investigation of a dry mummy

The challenging mission of paleopathologists is to be capable to diagnose a disease just on the basis of limited information gained by means of one or more paleodiagnostic techniques. In this study a radiologic, anthropologic and paleopathologic analysis of an ancient Egyptian mummy through X-rays, CT and MR was conducted. An Ancient Egyptian mummy ("Mistress of the house", Archeological Museum, Zagreb, Croatia) underwent digital radiography, computed tomography and magnetic resonance imaging employing 3-dimensional ultra-short-echo time (UTE) sequence, that allows to image ancient dry tissue. Morphological observations on the skull and pelvis, the stages of epiphyseal union and dental wear indicated that the remains are those of a young adult male. Multiple osseous lytic lesions were observed throughout the spine as well as on the frontal, parietal, and occipital bone, orbital wall and the sella turcica of the sphenoid. Considering the sex and age of the individual and the features of the lesions, the authors propose the diagnosis of Hand-Schueller-Christian's disease. This is the first study to have effectively used MR images in the differential diagnosis of a disease. It also confirmed the CT value in revealing central nervous system involvement just by detecting skeletal lesions. Although the mummy was previously dated to 3rd century B.C. based on the properties of the sarcophagi, the sex of the mummy suggests that it was most probably transferred into these sarcophagi in later times. The mummification techniques used and radiometric data (C14) dated it to 900-790. B.C.     

Three-dimensional cranial surface reconstructions using high-resolution computed tomography

Until recently, there has been no satisfactory way for anthropologists to visualize intracranial morphology in more than two dimensions without actually "invading" the skull in some manner. Images provided by conventional x-ray and computed tomography (CT) scans are often abstract, flat, two-dimensional representations that fail to reveal three-dimensional relationships. We describe new computer-imaging techniques that reconstruct three-dimensional images from sequential series of narrowly collimated (1-2 mm), high-resolution CT scans of the skull. These computed images represent three-dimensional surface data and can be viewed from any direction. Depth information is encoded in gray scale. In addition, selected portions of the anatomy can be "removed", i.e., made transparent, to allow visualization of previously hidden intracranial morphology. Since the geometric data obtained with the CT scanner are precise, parameters such as linear distances, angles, areas, and volumes can be accurately (and instantaneously) generated. The power and versatility of these computer-imaging techniques are demonstrated by examining living subjects with major craniofacial dysmorphology (Treacher-Collins syndrome and unilateral coronal synostosis); an anthropoid osteological specimen (Gorilla); and a fossil mammal skull.     

颅底孔在多层CT三维重建中的测量研究

探讨颅底MSCT三维重建图像效果及主要孔的正常值,采用多层螺旋CT(MSCT),对200名正常成人(男100名,女100名)进行颅脑扫描,利用电子计算机三维重建程序立体地显示颅底外面的卵圆孔、棘孔、颈动脉管外口、破裂孔、茎乳孔、枕骨大孔,并观察其形态和测出其内径及其性差。     

Volumic patient-specific reconstruction of muscular system based on a reduced dataset of medical images

Three-dimensional mechanical modelling of muscles is essential for various biomechanical applications and clinical evaluation, but it requires a tedious manual processing of numerous images. A muscle reconstruction method is presented based on a reduced set of images to generate an approximate parametric object from basic dimensions of muscle contours. A regular volumic mesh is constructed based on this parametric object. The approximate object and the corresponding mesh are deformed to fit the exact muscles contours yielding patient-specific geometry. Evaluation was performed by comparison of geometry to that obtained by contouring all computed tomography (CT) slices, and by quantification of the mesh quality criteria. Muscle fatty infiltration was estimated using a threshold between fat and muscle. Volumic fat index (VFI) of a muscle was computed using first all the complete CT scan slices containing the muscle (VFI(ref)) and a second time only the slices used for reconstruction (VFI(recons)). Mean volume error estimation was 2.6% and hexahedron meshes fulfilled quality criteria. VFI(recons) respect the individual variation of fat content.     

Anatomical Confirmation of Computed Tomography-Based Diagnosis of the Atherosclerosis Discovered in 17th Century Korean Mummy

In the present study on a newly discovered 17^th century Korean mummy, computed tomography (CT) revealed multiple aortic calcifications within the aortic wall that were indicative of ancient atherosclerosis. The CT-based findings were confirmed by our subsequent post-factum dissection, which exhibited possible signs of the disease including ulcerated plaques, ruptured hemorrhages, and intimal thickening where the necrotic core was covered by the fibrous cap. These findings are strong indicators that the mummy suffered from aortic atherosclerosis during her lifetime. The present study is a good example of how CT images of vascular calcifications can be a useful diagnostic tool in forming at least preliminary diagnoses of ancient atherosclerosis.     

Tomographic techniques for the study of exceptionally preserved fossils

Three-dimensional fossils, especially those preserving soft-part anatomy, are a rich source of palaeontological information; they can, however, be difficult to work with. Imaging of serial planes through an object (tomography) allows study of both the inside and outside of three-dimensional fossils. Tomography may be performed using physical grinding or sawing coupled with photography, through optical techniques of serial focusing, or using a variety of scanning technologies such as neutron tomography, magnetic resonance imaging and most usefully X-ray computed tomography. This latter technique is applicable at a variety of scales, and when combined with a synchrotron X-ray source can produce very high-quality data that may be augmented by phase-contrast information to enhance contrast. Tomographic data can be visualized in several ways, the most effective of which is the production of isosurface-based 'virtual fossils' that can be manipulated and dissected interactively.     

男性尿道直肠瘘数字化三维重建的初步应用

目的：基于CT扫描图象建立精确的男性尿道直肠瘘数字化模型,探讨其在临床诊断及治疗中的应用。方法：选择1例男性尿道直肠瘘病例,进行尿道CT连续断层扫描,扫描结果导入Mimics软件中进行三维重建,利用三维重建模型指导临床。结果：建立男性尿道直肠瘘及周围结构的三维立体模型,可以方便地从任意角度和方向观察瘘管情况,测量有关的数据;还可以在数字化模型上进行手术设计。结论：男性尿道直肠瘘的数字化三维模型能够更直观、准确地反映病变部位的三维立体结构。对男性尿道直肠瘘的诊断、手术规划等有较大帮助。     

Three-dimensional reconstruction of human diaphragm with the use of spiral computed tomography

Pettiaux, Nicolas, Marie Cassart, Manuel Paiva, and MarcEstenne. Three-dimensional reconstruction of human diaphragm withthe use of spiral computed tomography. J. Appl.Physiol. 82(3): 998-1002, 1997.We developed atechnique of diaphragm imaging by using spiral computed tomography, andwe studied four normal subjects who had been previously investigatedwith magnetic resonance imaging (A. P. Gauthier, S. Verbanck,M. Estenne, C. Segebarth, P. T. Macklem, and M. Paiva.J. Appl. Physiol. 76: 495-506,1994). One acquisition of 15- to 25-s duration was performed atresidual volume, functional residual capacity, functional residualcapacity plus one-half inspiratory capacity, and total lung capacitywith the subject holding his breath and relaxing. From theseacquisitions, 20 coronal and 30 sagittal images were reconstructed ateach lung volume; on each image, diaphragm contour in the zone ofapposition and in the dome was digitized with the software Osiris, andthe digitized silhouettes were used for three-dimensionalreconstruction with Matlab. Values of length and surface area for thediaphragm, the dome, and the zone of apposition were very similar tothose obtained with magnetic resonance imaging. We conclude thatsatisfactory three-dimensional reconstruction of the in vivo diaphragmmay be obtained with spiral computed tomography, allowing accurate measurements of muscle length, surface area, and shape.

     

Marker-free image registration of electron tomography tilt-series

Background  

Tilt series are commonly used in electron tomography as a means of collecting three-dimensional information from two-dimensional projections. A common problem encountered is the projection alignment prior to 3D reconstruction. Current alignment techniques usually employ gold particles or image derived markers to correctly align the images. When these markers are not present, correlation between adjacent views is used to align them. However, sequential pairwise correlation is prone to bias and the resulting alignment is not always optimal.     

Computer-designed prostheses for orbitocranial reconstruction

Three-dimensional imaging is an adjunct to preoperative evaluation and surgical management in some patients with complex anatomic defects of various etiologies. Deformities defined by conventional computerized tomography can be viewed as accurate three-dimensional images calculated from the original scan. The images are viewed on a high-resolution video monitor and can be photographed for a permanent record. A computer-controlled milling device can use these data to fabricate prostheses. The prostheses aid reconstructive surgery through use as an alloplastic implant, as a template to fashion autogenous bone grafts, or as a model for tissue removal. We have utilized three-dimensional imaging in combination with computer-assisted prosthesis manufacture in six patients with complex orbitocranial deformities. Four patients have undergone reconstructive surgery with satisfactory results and no complications thus far. The use of computer-designed prostheses adds a new aspect to orbitocranial reconstructive surgery that facilitates increased accuracy in the correction of anatomic defects.     

染色体三维结构重建方法研究

染色体三维结构重构问题是近年生物领域中基因组学的热点研究问题,是以二维交互频率数据为基础来预测其三维空间结构。最新相关实验表明染色质的三维空间结构对于基因表达、调控等方面都具有重要意义。而Hi-c数据能利用染色质交互信息形成二维接触矩阵重构出染色体三维结构。本综述以染色体三维结构重建方法为研究对象,通过对染色体三维结构重建方法进行比较分析,综述了目前基于Hi-c数据在染色体三维结构重建中的经典方法,系统介绍了染色体三维结构重建技术的发展脉络,以促进染色体三维结构重建的进一步研究。     

An ImageJ-based tool for three-dimensional registration between different types of microscopic images

Three-dimensional (3D) registration (i.e., alignment) between two microscopic images is very helpful to study tissues that do not adhere to substrates, such as mouse embryos and organoids, which are often 3D rotated during imaging. However, there is no 3D registration tool easily accessible for experimental biologists. Here we developed an ImageJ-based tool which allows for 3D registration accompanied with both quantitative evaluation of the accuracy and reconstruction of 3D rotated images. In this tool, several landmarks are manually provided in two images to be aligned, and 3D rotation is computed so that the distances between the paired landmarks from the two images are minimized. By simultaneously providing multiple points (e.g., all nuclei in the regions of interest) other than the landmarks in the two images, the correspondence of each point between the two images, i.e., to which nucleus in one image a certain nucleus in another image corresponds, is quantitatively explored. Furthermore, 3D rotation is applied to one of the two images, resulting in reconstruction of 3D rotated images. We demonstrated that this tool successfully achieved 3D registration and reconstruction of images in mouse pre- and post-implantation embryos, where one image was obtained during live imaging and another image was obtained from fixed embryos after live imaging. This approach provides a versatile tool applicable for various tissues and species.     

Exploiting desktop supercomputing for three-dimensional electron microscopy reconstructions using ART with blobs

Three-dimensional electron microscopy allows direct visualization of biological macromolecules close to their native state. The high impact of this technique in the structural biology field is highly correlated with the development of new image processing algorithms. In order to achieve subnanometer resolution, the size and number of images involved in a three-dimensional reconstruction increase and so do computer requirements. New chips integrating multiple processors are hitting the market at a reduced cost. This high-integration, low-cost trend has just begun and is expected to bring real supercomputers to our laboratory desktops in the coming years. This paper proposes a parallel implementation of a computation-intensive algorithm for three-dimensional reconstruction, ART, that takes advantage of the computational power in modern multicore platforms. ART is a sophisticated iterative reconstruction algorithm that has turned out to be well suited for the conditions found in three-dimensional electron microscopy. In view of the performance obtained in this work, these modern platforms are expected to play an important role to face the future challenges in three-dimensional electron microscopy.     

基于CT薄层扫描的骨盆数字化三维模型的分色构建

目的：探讨利用CT原始数据集对骨盆进行数字化三维分色构建的方法及意义。方法：选择1例因宫颈癌行盆腔CT薄层扫描患者的Dicom3．0原始二维断层数据集,利用Mimics10．01软件行骨盆三维分色重建。结果：构建的数字化三维分色模型形态规则、清晰逼真、立体感强、解剖清晰,不仅可以对构成骨盆的髂骨、骶骨及尾骨进行单独的三维分色显示,而且可以进行任意角度、距离的融合分离显示,更有利于对骨盆进行精细地全面立体观察分析。结论：基于CT薄层扫描数据集构建骨盆三维分色模型的方法简单、可行,是指导临床及教学的好工具。     

女性尿道阴道瘘数字化三维重建在临床治疗中的初步应用

目的:基于CT扫描图象建立精确的女性尿道阴道瘘数字化模型,探讨其在临床诊断及治疗中的应用。方法:选择1例女性尿道阴道瘘病例,进行尿道CT连续断层扫描,扫描结果导入Mimics软件中进行三维重建,利用三维重建模型指导临床。结果:建立女性尿道阴道瘘及周围结构的三维立体模型,可以方便地从任意角度和方向观察瘘管情况,测量有关的数据;还可以在数字化模型上进行手术设计。结论:女性尿道阴道瘘的数字化三维模型能够更直观、准确地反映病变部位的三维立体结构。对女性尿道阴道瘘的诊断、手术规划等有较大帮助。     

Rapid three-dimensional segmentation of the carotid bifurcation from serial MR images

The current trend in computational hemodynamics is to employ realistic models derived from ex vivo or in vivo imaging. Such studies typically produce a series of images from which the lumen boundaries must first be individually extracted (i.e., two-dimensional segmentation), and then serially reconstructed to produce the three-dimensional lumen surface geometry. In this paper, we present a rapid three-dimensional segmentation technique that combines these two steps, based on the idea of an expanding virtual balloon. This three-dimensional technique is demonstrated in application to finite element meshing and CFD modeling of flow in the carotid bifurcation of a normal volunteer imaged with black blood MRI. Wall shear stress patterns computed using a mesh generated with the three-dimensional technique agree well with those computed using a mesh generated from conventional two-dimensional segmentation and serial reconstruction. In addition to reducing the time required to extract the lumen surface from hours to minutes, our approach is easy to learn and use and requires minimal user intervention, which can potentially increase the accuracy and precision of quantitative and longitudinal studies of hemodynamics and vascular disease.     

Plant light interception can be explained via computed tomography scanning: demonstration with pyramidal cedar (Thuja occidentalis, Fastigiata)

BACKGROUND AND AIMS: Light interception by the leaf canopy is a key aspect of plant photosynthesis, which helps mitigate the greenhouse effect via atmospheric CO(2) recycling. The relationship between plant light interception and leaf area was traditionally modelled with the Beer-Lambert law, until the spatial distribution of leaves was incorporated through the fractal dimension of leafless plant structure photographed from the side allowing maximum appearance of branches and petioles. However, photographs of leafless plants are two-dimensional projections of three-dimensional structures, and sampled plants were cut at the stem base before leaf blades were detached manually, so canopy development could not be followed for individual plants. Therefore, a new measurement and modelling approach were developed to explain plant light interception more completely and precisely, based on appropriate processing of computed tomography (CT) scanning data collected for developing canopies. METHODS: Three-dimensional images of canopies were constructed from CT scanning data. Leaf volumes (LV) were evaluated from complete canopy images, and fractal dimensions (FD) were estimated from skeletonized leafless images. The experimental plant species is pyramidal cedar (Thuja occidentalis, Fastigiata). KEY RESULTS: The three-dimensional version of the Beer-Lambert law based on FD alone provided a much better explanation of plant light interception (R(2) = 0.858) than those using the product LV*FD (0.589) or LV alone (0.548). While values of all three regressors were found to increase over time, FD in the Beer-Lambert law followed the increase in light interception the most closely. The delayed increase of LV reflected the appearance of new leaves only after branches had lengthened and ramified. CONCLUSIONS: The very strong correlation obtained with FD demonstrates that CT scanning data contain fundamental information about the canopy architecture geometry. The model can be used to identify crops and plantation trees with improved light interception and productivity.     

A new method in computer-assisted imaging in neuroanatomy

A procedure is described yielding computed images of postmortem brains with high topographic accuracy. Structures of the brain are traced and registered by means of a digitizer capable of measuring coordinates three-dimensionally. The information corresponding to one brain model is stored on a flexible disk with a capacity of 256 Kbytes. According to the output desired, the resulting brain images are either completely or partially displayed on the computer screen as stereo pairs. The brain models possess a local fidelity of about 1 mm. The images are useful in simultaneously studying superficial and central parts of the brain, spatial relationships of the various structures and the projection of deep structures onto the surface of the brain. A RAM of about 100 Kbytes is necessary for a program enabling the user to perform stereo projections, three-dimensional transformations and other image manipulations. The special features of anatomical computer imaging as compared to computed tomography (CT) and nuclear magnetic resonance imaging (NMR) are outlined. A combination of these different techniques seems to improve clinical diagnosis.