基于CT和MRI影像数据融合构建个体化OA膝关节三维解剖模型

目的探究一种基于CT和MRI影像数据融合构建包含主要解剖结构的骨关节炎(OA)膝关节三维模型的方法,并准确表达膝关节OA的解剖学特征。方法采集膝关节OA患者的CT和MRI影像数据,以DICOM格式导入Mimics软件中构建膝关节骨性结构模型和非骨性结构模型,基于图像特征的同层多点至多点的配准方法进行配准融合,构建OA膝关节三维解剖模型。结果基于CT和MRI影像数据融合构建出包括膝关节骨骼及关节软骨、半月板、韧带等结构的膝关节OA三维解剖模型,模型显示了关节间隙狭窄、半月板损伤、关节软骨磨损等膝关节OA的解剖学特征。结论通过CT和MRI影像数据融合可以个体化构建膝关节OA三维解剖模型,该模型能够真实且直观地展示骨性结构和非骨性结构的解剖学特征和空间解剖关系,为相关解剖学及生物力学研究提供三维解剖模型。     

基于CT和解剖的三维数字化腕关节模型的构建

目的 探讨基于CT影像重建和虚拟解剖复位的三维数字化腕关节模型的构建及其应用价值,为开展腕关节生物力学功能研究准备前处理形态学模型.方法 采集1例中国青年男性志愿者右前臂高分辨CT图像,应用Mimics软件进行三维骨性重建;通过腕关节标本解剖和数值调查,应用3D-Doetor软件在CT图像软组织灰度区域,分割三角纤维软骨盘和韧带群并三维重建;将骨结构、软骨盘和韧带群导入Geomagic软件进行虚拟解剖复位和模型配准,构建网格优化的腕关节数字模型.结果 建立了包括桡、尺骨,掌骨(包含皮质、松质、髓腔),腕骨,三角纤维软骨复合体,桡腕背侧、桡舟、桡舟头、桡月韧带等结构的三维数字化腕关节模型.模型虚拟构建的韧带、软骨盘等的测量值基本在文献报告的数值范围之内.结论 在目前的个人计算机平台上依据CT影像和解剖资料,利用医学图像处理软件和三维重建软件可以准确、快捷地构建腕关节的三维数字模型,为腕部有限元分析及整个虚拟手的构建提供了技术支撑.     

基于CT和解剖的三维数字化腕关节模型的构建

目的 探讨基于CT影像重建和虚拟解剖复位的三维数字化腕关节模型的构建及其应用价值,为开展腕关节生物力学功能研究准备前处理形态学模型.方法 采集1例中国青年男性志愿者右前臂高分辨CT图像,应用Mimics软件进行三维骨性重建;通过腕关节标本解剖和数值调查,应用3D-Doetor软件在CT图像软组织灰度区域,分割三角纤维软骨盘和韧带群并三维重建;将骨结构、软骨盘和韧带群导入Geomagic软件进行虚拟解剖复位和模型配准,构建网格优化的腕关节数字模型.结果 建立了包括桡、尺骨,掌骨(包含皮质、松质、髓腔),腕骨,三角纤维软骨复合体,桡腕背侧、桡舟、桡舟头、桡月韧带等结构的三维数字化腕关节模型.模型虚拟构建的韧带、软骨盘等的测量值基本在文献报告的数值范围之内.结论 在目前的个人计算机平台上依据CT影像和解剖资料,利用医学图像处理软件和三维重建软件可以准确、快捷地构建腕关节的三维数字模型,为腕部有限元分析及整个虚拟手的构建提供了技术支撑.     

准确构建个体化膝关节有限元解剖模型的方法

目的利用多模态影像数据融合和多种建模软件协同应用的方法准确构建膝关节有限元解剖模型,为研究膝关节生物力学行为奠定基础。方法采集正常膝关节CT和MRI影像数据,导入Mimics软件,提取骨、软骨、韧带和半月板,分别构建三维工程化模型。以外部标记物为参照进行模型的配准融合。将膝关节工程化模型导入SC/Tetra和Hypermesh软件,分别进行干涉面删除、网格自定义划分、局部网格优化和体网格划分,构建包含多解剖结构的膝关节有限元模型。结果基于CT和MRI影像数据构建出膝关节骨、软骨、韧带和半月板的三维工程化模型。以三维工程化模型为基础,多种建模软件协同应用构建的有限元模型充分保持了膝关节各结构的解剖学特征。结论利用CT和MRI影像数据融合和多种建模软件协同应用的方法可以构建活体膝关节有限元模型,并保持膝关节各解剖结构的解剖真实性,为准确模拟膝关节生物力学特征提供前提。     

多源医学影像数据重构膝关节骨与韧带结构的三维工程化模型

目的利用多源医学影像数据重构人体活体膝关节骨与韧带结构的三维工程化模型,探索数字医学研究在临床应用的方法。方法采集无损伤膝关节CT和MRI影像数据,导入重构软件。提取骨与韧带结构分别构建三维工程化模型。以外部标记物为参照进行三维工程化模型的配准和融合。结果基于CT和MRI影像数据构建出膝关节骨与韧带结构的三维工程化模型,清楚显示了膝关节骨骼和韧带的空间立体位置关系。结论人体活体多源影像数据重构三维工程化模型技术不同于传统可视化三维重建技术,为数字医学研究的临床应用提供了可行的方法。     

数字化虚拟手若干关键技术的研究

目的 应用数字化技术构建手的骨骼血管等解剖结构,探讨手解剖结构的数字化虚拟技术.方法 采用3具新鲜成人手标本,灌注前行CT预扫描,经自凝牙托材料及以硫化汞灌注处理4～24h后再进行CT扫描共获取220层数据集,利用Mimics软件对图像进行配准、分割、标识、重建手的外形、骨骼、动脉、指伸屈肌腱、神经等结构.结果 建立了基于解剖结构的可视化手模型,各结构可单独、联合显示,可旋转缩放,模型透视及多剖面显示,血管管腔显示中空逼真,手部神经可部分显示.结论 手可视化模型可为临床提供三维形态学资料,也为虚拟现实技术提供数字化模型.     

计算机辅助颈椎椎弓根螺钉置入参数的获取

目的探讨利用CT三维重建技术模拟颈椎椎弓根螺钉置入的方法,以获得预置螺钉的椎弓根三维定量解剖数据及置钉参数。方法将颈椎16排CT扫描的数据导入Mimics8．1软件中,进行颈椎CT三维重建,在三维图像上构建一圆柱体来模拟椎弓根螺钉,并置入颈椎椎弓根内,然后测量各项置钉参数。结果应用CT三维重建技术可以获得清晰的颈椎三维图像,使用软件测量功能可精确地获取预置螺钉的椎弓根解剖数据（椎弓根宽度和轴线长度）和置钉参数（置钉的α角、β角以及置钉α角安全范围）。结论通过CT三维重建技术获取椎弓根螺钉置入个体化三维数据,为术中实施颈椎椎弓根螺钉置入提供依据,是颈椎椎弓根螺钉置入安全性研究的一种可靠方法。     

踝关节与跟骨骨折数字化虚拟可视重建的初步研究

目的探讨数字化虚拟可视技术在足踝部骨折建模及其临床应用的可行性与价值。方法利用“虚拟中国人”女1号及足踝部骨折患者CT扫描图像及其数据集，将数据导人相应软件，重建足踝部正常解剖结构的三维可视模型，选取踝关节骨折、跟骨骨折患者进行内固定手术的初步计算机模拟并立体显示。结果重建了足踝部正常解剖及踝关节、跟骨骨折的三维可视模型，准确反映出其解剖学特点、骨折移位的方向和程度，并可进行任意旋转、剖切等观察和操作，初步实现踝关节骨折内固定手术的计算机模拟。结论数字化虚拟可视技术的应用可以提供三维解剖模型，可能为足踝部骨折的数字化分型、临床诊治方式的选择与改进等提供更为精准的解剖学及影像学依据。     

膝关节有限元解剖模型的构建及其力学分析

目的通过多模态CT和MRI影像数据融合构建膝关节有限元解剖模型,并进行有限元分析和验证,为膝关节力学仿真研究提供可靠的有限元模型。方法采集正常膝关节CT和MRI影像数据,导入到Mimics软件中,构建膝关节骨骼、半月板、关节软骨、韧带等结构的三维模型。以外部标记为参照点进行模型配准,融合成膝关节整体模型。在Hypermesh软件中进行网格划分,构建膝关节有限元模型。通过解剖观察和测量对有限元模型进行解剖真实度评估,对其设置材料属性、建立边界条件和施加载荷,进行有限元分析,并验证。结果基于CT和MRI影像数据构建出包含骨骼、半月板、关节软骨、韧带等多种组织结构的膝关节有限元整体模型,模型保持了膝关节的解剖学特征,有限元分析结果与文献报道的结果一致,显示有限元模型可靠、有效。结论通过多模态CT和MRI影像数据融合可以构建符合解剖学特征的膝关节有限元整体模型,能为研究膝关节生物力学行为提供可靠、有效的有限元模型。     

虚拟肝技术在肝癌治疗中的应用

虚拟肝是利用外科学、临床解剖学、现代影像学、计算机图形学、图像处理和虚拟现实技术进行多学科交叉研究,研发出计算机软件系统,利用患者的CT图像信息构建虚拟的三维可视化肝脏,并实现诊疗需要的各种功能.虚拟肝技术应用于肝癌治疗已成为一个新的研究热点.     

A three-dimensional interactive virtual dissection model to simulate transpetrous surgical avenues

OBJECTIVE: This project involves the development of a three-dimensional surgical simulator called interactive virtual dissection, which is designed to teach surgeons the visuospatial skills required to navigate through a transpetrosal approach. METHODS: A robotically controlled microscope is used for surgical planning and data collection. The spatial anatomic data are recorded from sequentially deeper cadaveric head dissections as a series of superimposed anatomic pictures in stereoscopic digital format. The sequential series of images are then merged to form the final virtual representation. RESULTS: The current three-dimensional virtual reality simulator allows the user to drill the petrous bone progressively deeper and to identify crucial structures much like an experienced surgeon drilling the petrous bone. The program allows surgeons and trainees to manipulate the virtual "surgical field" by interacting with the surgical anatomy. The interactive system functions on a desktop computer. CONCLUSION: The ability to visualize and understand anatomic spatial relationships is crucial in surgical planning, as is a surgeon's confidence in performing the surgery. The virtual reality simulator does not replace the need for practicing surgery on cadavers. However, it is designed to facilitate, via stereoscopic projection, learning how to manipulate a drill in complicated or unfamiliar surgical approaches (e.g., a transpetrosal approach).     

The virtual nose: a 3-dimensional virtual reality model of the human nose

BACKGROUND: The 3-dimensionally complex interplay of soft tissue, cartilaginous, and bony elements makes the mastery of nasal anatomy difficult. Conventional methods of learning nasal anatomy exist, but they often involve a steep learning curve. Computerized models and virtual reality applications have been used to facilitate teaching in a number of other complex anatomical regions, such as the human temporal bone and pelvic floor. We present a 3-dimensional (3-D) virtual reality model of the human nose. METHODS: Human cadaveric axial cross-sectional (0.33-mm cuts) photographic data of the head and neck were used. With 460 digitized images, individual structures were traced and programmed to create a computerized polygonal model of the nose. Further refinements to this model were made using a number of specialized computer programs. This 3-D computer model of the nose was then programmed to operate as a virtual reality model. RESULTS: Anatomically correct 3-D model of the nose was produced. High-resolution images of the "virtual nose" demonstrate the nasal septum, lower lateral cartilages, middle vault, bony dorsum, and other structural details of the nose. Also, the model can be combined with a separate virtual reality model of the face and its skin cover as well as the skull. The user can manipulate the model in space, examine 3-D anatomical relationships, and fade superficial structures to reveal deeper ones. CONCLUSIONS: The virtual nose is a 3-D virtual reality model of the nose that is accurate and easy to use. It can be run on a personal computer or in a specialized virtual reality environment. It can serve as an effective teaching tool. As the first virtual reality model of the nose, it establishes a virtual reality platform from which future applications can be launched.     

Value of high-resolution computed tomography in diagnosis of petrous bone fracture

High-resolution computed tomography (CT) was performed on 31 patients clinically suspected of having petrous bone fracture. The location of the fracture was demonstrated accurately in 28 patients (90.3%), whereas it could be diagnosed by plain skull film in only 17 patients (54.8%). The anatomic location of fractures demonstrated by high-resolution CT clearly corresponded to the clinical symptoms and signs. We have classified petrous bone fracture into five types according to the anatomic levels demonstrated on CT images. The findings indicate that highresolution CT is extremely useful for diagnosing petrous bone fracture.     

IERAPSI project: simulation of a canal wall-up mastoidectomy.

Among the various EU research projects concerning the medical application of virtual reality, the project Ist-1999-12175, called IERAPSI (Integrated Environment for the Rehearsal and Planning of Surgical Interventions), specifically addressed the creation of a virtual and interactive surgical field for the temporal bone using three-dimensional images derived from CT data. We report on the experience obtained in the IERAPSI project in simulating a canal wall-up mastoidectomy. A surgeon with extensive experience in surgery of the petrous bone performed the mastoidectomy. The operative field included the mastoid, with its substantial differences in density between the cortex and the pneumatized bone, together with soft tissue structures, both on the border and inside the bone. The simulation is better in the first part of the operation than in the second part, suffering from a lack of haptic feedback from soft tissue and the surgical tool in deeper contexts, and under-representation of the variability inherent in pneumatized bone. This said, the excellent representation of dust production and removal, 3D simulation through color, and very good visual and haptic feedback in the early stage of the procedure are impressive. IERAPSI represents a potential surgical planning theater for the training of students and young surgeons, but is also expected to aid expert surgeons in the preoperative planning of difficult cases.     

颞下经岩骨嵴入路的应用解剖学研究

目的提出颞下经岩骨嵴入路切除岩斜区脑膜瘤的方法,使手术更加简便、安全、微创,以替代各型联合入路,降低手术致残、致死率。方法10%甲醛固定的国人成人头颅湿标本10例、漂白的颅骨干标本10例,模拟手术操作并对手术涉及的重要结构测量、拍照;手术前后共10例20侧标本进行CT岩骨薄扫,并对重要结构进行测量、拍照。结果颞下经岩骨嵴入路涉及的重要解剖结构包括Labbe静脉、岩骨内部结构、脑干腹侧间隙等。重要参数包括岩骨嵴磨除范围。结论颞下经岩骨嵴入路通过对岩骨嵴的磨除,增加对岩骨背侧肿瘤基底的暴露,适合切除骑跨中后颅窝的岩斜脑膜瘤。该入路具有操作简单、创伤小、安全性高的特点。     

虚拟现实技术在神经外科术前计划中的应用

目的探讨虚拟现实（virtual reality，VR）技术在神经外科术前计划中的临床应用价值。方法对拟采用手术治疗的颅脑疾病26例，分别采集磁共振成像（MRI）、磁共振动脉成像（MRA）、磁共振静脉成像（MRV），计算机体层摄影（CT）等多种医学影像数据，输入Dextroscope术前计划系统，运用Radiodexter软件在VR环境中进行融合、提取、切割等处理显示为一个三维立体物像。同时运用软件内的三维处理工具对病灶及其局部解剖结构进行观察测量、手术模拟。制定术前计划，并与真正手术中情况进行对照比较。结果26例病例均成功地实现了三维立体虚拟现实影像的重建，术前计划中对于病灶及其局部解剖学特征的判定与术中实际情况吻合。结论Dextroscope系统的虚拟现实技术能快速、直观、全面地整合多种医学影像数据，以提供病灶及其局部解剖结构的综合信息，在神经外科手术前为制定和优化手术方案提供帮助，有可能有助于提高手术的安全性与病灶的全切除率。     

Three-dimensional computed tomographic cranial base measurements for improvement of surgical approaches to the petrous carotid artery and apex regions

OBJECTIVE: The bony and vascular anatomic features in the region of the petrous apex can vary significantly. These variations affect the operative view obtained via extended subtemporal or anterior transpetrosal approaches to cranial base lesions for individual patients. The goal of this study was to evaluate three-dimensional computed tomography as a means of obtaining detailed preoperative anatomic information regarding bony and vascular landmarks and spatial relationships in the region of the petrous carotid artery and petrous apex. METHODS: We radiographically studied 15 patients (30 sides), using 0.8- to 1-mm-thick, reconstructed, computed tomographic images. Special attention was given to the course of the petrous carotid artery. RESULTS: The petrous carotid artery was located lateral to the trigeminal impression. The size of the petrous apex medial to the horizontal petrous carotid artery was observed to be variable. The width of bone from the trigeminal impression to the wall of the internal auditory canal averaged 9.6 mm (range, 5.2-16.1 mm). A variable amount of bone overlying the internal auditory canal (4.5 mm) was also present. Multiple other relationships among key landmarks were quantified. CONCLUSION: There is significant variability in the anatomic features of the petrous apex among patients. For each patient, detailed preoperative information regarding the amount of bone to be removed during a cranial base procedure can be obtained using three-dimensional computed tomography. This information may be critical for determination of the amount of extra exposure that can be achieved via an anterior petrosectomy for each patient.     

Computer-assisted LISS plate osteosynthesis of proximal tibia fractures: feasibility study and first clinical results.

Fluoroscopy is the most common tool for the intraoperative control of long-bone fracture reduction. Limitations of this technology include high radiation exposure for the patient and the surgical team, limited visual field, distorted images, and cumbersome verification of image updating. Fluoroscopy-based navigation systems partially address these limitations by allowing fluoroscopic images to be used for real-time surgical localization and instrument tracking. Existing fluoroscopy-based navigation systems are still limited as far as the virtual representation of true surgical reality is concerned. This article, for the first time, presents a reality-enhanced virtual fluoroscopy with radiation-free updates of in situ surgical fluoroscopic images to control metaphyseal fracture reduction. A virtual fluoroscopy is created using the projection properties of the fluoroscope; it allows the display of detailed three-dimensional (3D) geometric models of surgical tools and implants superimposed on the X-ray images. Starting from multiple registered fluoroscopy images, a virtual 3D cylinder model for each principal bone fragment is constructed. This spatial cylinder model not only supplies a 3D image of the fracture, but also allows effective fragment projection recovery from the fluoroscopic images and enables radiation-free updates of in situ surgical fluoroscopic images by non-linear interpolation and warping algorithms. Initial clinical experience was gained during four tibia fracture fixations that were treated by LISS (Less Invasive Stabilization System) osteosynthesis. In the cases operated on, after primary image acquisition, the image intensifier was replaced by the virtual reality system. In all cases, the procedure including fracture reduction and LISS osteosynthesis was performed entirely in virtual reality. A significant disadvantage was the unfamiliar operation of this prototype software and the need for an additional operator for the navigation system.     

Computer aided long bone fracture treatment

Intraoperative fluoroscopy is the tool for intraoperative control of long bone fracture reduction and osteosynthesis. Limitations of this technology include: High radiation exposure to the patient and the surgical team, limited field of view, image distortion, limitation to 2-D representations, and cumbersome updating of verification images. Fluoroscopy based navigation systems partially address these limitations by allowing fluoroscopic images to be used for real-time surgical localization and instrument tracking. In a clinical study on computer guidance by virtual fluoroscopy for distal locking, the capability to provide online guidance with significantly reduced fluoroscopy times is demonstrated. Virtual fluoroscopy applied for guidewire placement in a laboratory setup demonstrated the potential of the method to reduce procedure times, and the potential to increase precision of implant placement with decreased fluoroscopy times. By using virtual reality enhancement, starting from multiple registered fluoroscopy images, a virtual 3-D cylinder model for each principal bone fragment is reconstructed. This spatial cylinder model is not only used to supply a 3-D image of the fracture, but also allows effective fragment projection extraction from the fluoroscopic images and further achieves radiation-free updates of in-situ surgical fluoroscopic images through a non-linear interpolation and warping algorithm. After primary image acquisition, the image intensifier was replaced by the virtual reality system. It was shown that all the steps of the procedure, including fracture reduction and LISS osteosynthesis can be performed completely in virtual reality.     

Assessment of the anatomical relationship between the arcuate eminence and superior semicircular canal by computed tomography

The anatomical relationship between the arcuate eminence (AE) and the superior semicircular canal (SSC) was examined by computed tomography (CT) in 52 petrous bones of 26 patients. After acquiring volume data by multidetector CT, 1-mm thick oblique bone window images perpendicular to the SSC were obtained from the axial images. The distances between the AE and the SSC, and the SSC and the superior surface of the petrous bone were measured. The AE corresponded exactly with the SSC in only 2/52 petrous bones, and corresponded well in 7/52. The AE was lateral to the SSC in 25/52 cases, medial to the SSC in 6/52 cases, intersected in 3/52 cases, and was indiscernible in 9/52 cases. The distance between the SSC and the petrous surface was 0 mm in 45/52 petrous bones, 1 mm in 5/52, 2 mm in 1/52, and 3 mm in 1/52. The SSC typically does not correspond exactly with the AE, and is generally located just under the surface of the petrous bone. Planning of the middle cranial fossa approach requires location of the SSC by CT.