先天性耳畸形和正常颞骨的螺旋CT三维成像分析

目的：探讨螺旋CT扫描及三维重建成像技术在先天性耳畸形和正常颞骨的临床应用，方法：采用螺旋高分辨CT扫描技术，对16例先天性，中耳畸形及40例正常耳行多平面重建，曲面重建和三维表面成像，结果：16侧患耳畸形为：外耳道骨性闭锁，鼓室狭小，听小骨发育不育，面神经管异常等。小视野密集重建清晰显示了细微结构，多平面重建提供多位信息，三维表面成像立体直观地显示形态结构，结论：螺旋高分辨CT及三维重建成像技术有利于外，中、内耳正常结构的显示和先天畸形的诊断，三维重建成像技术能提供更多的诊断信息，建议临床选择应用。     

Generation of three dimensional images from CT scans: technological perspective

Routine production of three dimensional (3-D) surface images from CT scans for clinical applications has been performed in 700 cases. These images have been found useful in craniofacial, orthopedic, and neurosurgical applications. Three dimensional images may be produced on the same CT scanner that collected the original slices. The emergence of 3-D imaging as a routine radiological procedure involves special technological requirements to avoid artifacts and to produce a useful result. Three dimensional surface reconstruction procedures are reviewed and examples of clinical application are presented.     

多层螺旋CT后处理在骨肿瘤诊断中的临床价值

目的评价多层螺旋CT(MSCT)后处理在骨肿瘤诊断中的临床价值。资料与方法34例骨肿瘤患者行MSCT扫描后，做多层面重建(MPR)，最大强度投影(MIP)，三维重建(3D)，四维重建(4D)4种后处理。结果每一种重建图像均显示了所有的肿瘤。MPR准确显示了肿瘤的范围及细微结构；MIP及3D能立体显示骨改变；4D能立体显示骨改变及肿瘤的范围和细微结构。4种后处理图像结合横断层面原始图像能从不同方向准确显示肿瘤的范围、骨改变及骨膜反应的形态。结论MSCT后处理对病变的显示全面准确，结合横断面图像，可对骨肿瘤做出准确的评价。     

基于Amira软件的小腿外侧供区皮瓣三维可视化设计

目的 利用个人电脑(PC),结合图像处理软件Amira 4.1对小腿外侧皮瓣进行三维重建,建立皮瓣动脉的可视化数字模型.方法 明胶-氧化铅混悬液灌注的新鲜成人标本1具,行下肢多排螺旋CT扫描,观测腓动脉的分布及彼此间的吻合情况,将数据输入个人PC,利用Amira软件,经剪切、分割、表面重建及体绘制等步骤,根据解剖结构特点,对皮肤及其血管进行三维重建,获得立体形态的动脉皮瓣结构.结果 重建了皮瓣主要构成,重建的三维结构可以多彩色、透明或任意组合显示,经不同角度观察,整体显示清晰、实体感强,皮肤、动脉的相互关系一目了然.在三维表面重建的图像中可清楚地观察各解剖结构的形态,特别是皮瓣动脉的分支及其体表投影得到了很好的显示.结论 小腿外侧皮瓣三维重建对基础研究、临床试验及手术规划具有重要价值,应用Amira软件可为三维建模提供基础.     

Automatic segmentation and 3D reconstruction of intravascular ultrasound images for a fast preliminar evaluation of vessel pathologies

Intravascular ultrasound (IVUS) imaging is used along with X-ray coronary angiography to detect vessel pathologies. Manual analysis of IVUS images is slow and time-consuming and it is not feasible for clinical purposes. A semi-automated method is proposed to generate 3D reconstructions from IVUS video sequences, so that a fast diagnose can be easily done, quantifying plaque length and severity as well as plaque volume of the vessels under study. The methodology described in this work has four steps: a pre-processing of IVUS images, a segmentation of media–adventitia contour, a detection of intima and plaque and a 3D reconstruction of the vessel. Preprocessing is intended to remove noise from the images without blurring the edges. Segmentation of media–adventitia contour is achieved using active contours (snakes). In particular, we use the gradient vector flow (GVF) as external force for the snakes. The detection of lumen border is obtained taking into account gray-level information of the inner part of the previously detected contours. A knowledge-based approach is used to determine which level of gray corresponds statistically to the different regions of interest: intima, plaque and lumen. The catheter region is automatically discarded. An estimate of plaque type is also given. Finally, 3D reconstruction of all detected regions is made.The suitability of this methodology has been verified for the analysis and visualization of plaque length, stenosis severity, automatic detection of the most problematic regions, calculus of plaque volumes and a preliminary estimation of plaque type obtaining for automatic measures of lumen and vessel area an average error smaller than 1 mm² (equivalent aproximately to 10% of the average measure), for calculus of plaque and lumen volume errors smaller than 0.5 mm³ (equivalent approximately to 20% of the average measure) and for plaque type estimates a mismatch of less than 8% in the analysed frames.     

Virtual endoscopy of the middle ear: experimental and clinical results of a standardised approach using multi-slice helical computed tomography

Virtual endoscopy (VE) enables non-invasive 3D endoluminal imaging of the middle ear by post-processing of CT data. To optimise the clinical application a standardised approach was evaluated in normal and pathologic cases. Data acquisition was performed using multi-slice helical CT in 20 normal patients and 15 patients with malformation or trauma. Virtual endoscopy of the tympanic cavity and 3D images of the ossicles were generated using surface and volume rendering. Qualitative assessment of the representation of anatomical structures was performed in normal patients. In 15 pathological cases the diagnostic benefit was evaluated by comparing the 3D images to the 2D images and intra-operative findings. In all 35 cases 3D imaging was possible using the standardised approach. The ossicular chain as well as the bony and soft tissue structures of the tympanic cavity were visualised in 20 normal patients. In 7 of 8 patients with malformation and 1 of 7 patients with trauma the original diagnosis was changed by 3D imaging. Standardisation and evaluation of the method in normal patients is essential as it enhances the diagnostic reliability. Virtual endoscopy facilitates understanding of the complex anatomy of the middle ear. In cases of suspected malformation and confirmed trauma it is helpful for diagnosis and surgical planning.     

Three-dimensional computed tomography in the head and neck diseases with bony abnormalities

The purpose of this study was to define the role of three-dimensional (3D) computed tomography (CT) in the head and neck diseases with bony abnormalities. Thirty-two patients were examined with a low dose radiation technique. Three-dimensional CT clearly delineated bony lesions in 27 of 32 patients. Three-dimensional CT could not demonstrate subtle bony erosions infiltrated by tumor, a temporal bone fracture, and a blow-out fracture, although two-dimensional (2D) images obtained before the 3D reconstructions clearly depicted those lesions. These two kinds of CT technique were thought to be complimentary.     

Radiographic examination of the temporomandibular joint using cone beam computed tomography

Cone beam CT (CBCT) is a new technique for maxillofacial imaging. We describe a reconstruction technique for radiographic examination of the temporomandibular joint (TMJ) using CBCT, and we further present four cases where the technique was employed. The technique provides a complete radiographic investigation of the bony components of the TMJ. The reconstructed images are of high diagnostic quality. The examination time is shorter and the patient dose is lower than that with conventional CT. It may therefore be considered as the imaging technique of choice when investigation of bony changes of the TMJ is the task at hand.     

16层螺旋CT三维和多平面重组对儿童先天性脊柱侧弯的评价

目的 运用16层螺旋CT三维（3D）和多平面重组技术对先天性脊柱侧弯患儿进行评估，探讨此技术的优势和临床指导意义。方法 搜集2004年4至10月司27例先天性脊柱侧弯患儿的影像学资料，男13例，女14例，中位年龄3岁。27例均进行了X线片、16层螺旋CT容积3D、标准和曲面多平面重组技术。结果 10例患者有分节异常，6例患者有形成异常，11例患者有复杂的、无法分类的畸形。15例肋骨畸形中，肋骨畸形的主要部分和脊柱旋转在同水平的有7例。8例合并脊髓纵裂，其中6例有完全或不完全的骨性隔。27例中的19例患者，多平面重组和3D图像显示出在常规X线片和常规轴面图像中未发现和认知的畸形并且全面评估了脊柱侧弯的程度，包括11例复杂畸形中7例归类为无法分类的脊柱畸形，4例为单侧未分节的骨桥合并同侧半椎体畸形；4例清晰显示出单侧未分节的骨桥（3例）和双侧骨桥融合（1例）；2例发现了掩蔽的半椎体畸形；2例重新评估了半椎体的类型和数目；27例曲面多平面重组图像更好的显示了椎管形态和脊髓弯曲情况，6例清晰显示椎管内骨性隔的生长方式和形态；4例患者标准多平面重组更好的显示了颅底-C1-C2的解剖和畸形，尤其是颅颈联合部畸形。结论 16层螺旋CT3D和标准或曲面多平面重组图像是诊断先天性脊柱侧弯、分析复杂多发或隐蔽脊柱和肋骨畸形的首选方法，在评价儿童脊柱侧弯的进展、修订手术方案较常规平片和（或）常规CT更具优势和指导意义。     

Dental-CT bei pathologischen Veränderungen im Bereich des Kiefers

CT with multiplanar reconstruction of the jaws (DentaScan) is the method of choice for the radiographic assessment of the mandible and maxilla. It is instrumental in delineating the relationship between bony lesions and the adjacent anatomy. Therefore, this technique allows precise evaluation of the intricate details of the oral cavity. Using it, distinct characterization of pathology including infectious, metabolic, congenital and neoplastic lesions can be obtained.     

正常颅底的CT三维重建及其临床价值

目的：应用ＣＴ三维重建（３ＤＣＴ）研究颅底的正常解剖结构，为临床诊断及治疗提供直观的立体信息。材料与方法：选择颅底二维图像正常的１０例正常人，先做薄层高分辨力ＣＴ扫描，将二维数据输入工作站做三维重建。然后将三维重建图像与颅底标本做对照。结果：三维重建可从不同角度描述并展示颅底的正常解剖。结论：三维重建能清楚显示颅底的结构，为临床提供２Ｄ图像不能显示的立体观，特别是为手术方式和入路的选择提供依据     

螺旋CT三维成像在颞部及颜面部的应用

目的评价螺旋ＣＴ三维成像技术对颞部及颜面部病变的诊断作用。方法对１９例颞部病变和１７例颜面部病变进行了高速螺旋扫描和三维重建，并从多方向观察三维重建图像。使用的螺旋ＣＴ装置为东芝ＸＦｏｒｃｅ、螺旋ＣＴ三维成像装置为ＸＬｉｎｋ５０。结果螺旋ＣＴ三维成像技术能清楚地立体显示病变的部位和范围。结论螺旋ＣＴ三维成像技术能对颞部及颜面病变的术前诊断提供有价值的信息和发挥重要作用     

3D/2D registration and segmentation of scoliotic vertebrae using statistical models.

We propose a new 3D/2D registration method for vertebrae of the scoliotic spine, using two conventional radiographic views (postero-anterior and lateral), and a priori global knowledge of the geometric structure of each vertebra. This geometric knowledge is efficiently captured by a statistical deformable template integrating a set of admissible deformations, expressed by the first modes of variation in Karhunen-Loeve expansion, of the pathological deformations observed on a representative scoliotic vertebra population. The proposed registration method consists of fitting the projections of this deformable template with the preliminary segmented contours of the corresponding vertebra on the two radiographic views. The 3D/2D registration problem is stated as the minimization of a cost function for each vertebra and solved with a gradient descent technique. Registration of the spine is then done vertebra by vertebra. The proposed method efficiently provides accurate 3D reconstruction of each scoliotic vertebra and, consequently, it also provides accurate knowledge of the 3D structure of the whole scoliotic spine. This registration method has been successfully tested on several biplanar radiographic images and validated on 57 scoliotic vertebrae. The validation results reported in this paper demonstrate that the proposed statistical scheme performs better than other conventional 3D reconstruction methods.     

多层面CT重建诊断中央大气道良性病变

目的 :分析多层面CT三维重建诊断中央大气道良性病变的价值。材料和方法 :用多层面CT对 3 5例中央气道良性病变 (解剖性异常 5例 ,炎症性病变 18例及其它 12例 )扫描 ,并全部完成三维表面遮盖显示、容积显示和仿真内窥镜检查。所有病例第一次读片时仅有横断面图像 ,第二次读片时增加重建图像。结果 :三维重建帮助 4例横断面漏误诊的解剖性异常获得确诊 ,16例炎症性病变进一步详细显示 ,2例气管支气管裂伤明确范围和程度 ;虚拟内窥镜帮助 5例横断面上不能确诊的痰液获得确诊。结论 :CT三维重建可用于解剖性异常和痰液的诊断 ,对其它良性疾病主要是对病变的另一种形式的进一步显示。     

Evaluation of CT techniques for reducing artifacts in the presence of metallic orthopedic implants

Metallic intramedullary orthopedic implants generate artifacts that can markedly degrade transaxial CT images. The artifacts, typically seen as starburst streaking, result primarily from reconstructions involving missing projection data. Two approaches are clinically available to reduce the artifacts around orthopedic implants. These are (a) the imaging of implants with lower attenuation coefficients or smaller path lengths (less attenuating objects) and (b) the planar reformatting of image data. The sizing accuracy of these two approaches was quantified using phantoms and the efficacy using cadaveric femoral specimens. Results demonstrated that metal artifacts may be reduced and accurate bony dimensional data obtained.     

128层螺旋CT的MPR和VR在胫骨平台骨折中的应用

目的：探讨螺旋CT MPR和三维重建（3D-CT）技术在胫骨平台骨折中的临床应用。方法：回顾性分析经128层螺旋CT的MPR和3D技术证实的60例胫骨平台骨折病例。结果：所有胫骨平台骨折经3D及MPR成像后均能立体显示骨折的部位、形态、类型、关节面碎裂及塌陷程度等空间信息,较平片优越,与手术中所见一致。结论：螺旋CT的MPR及3D技术能够更精确地显示胫骨平台的骨折情况,对骨折的分型判断及治疗方法的选择具有指导意义。     

螺旋CT三维重建技术在上气道病变中的临床价值

目的　探讨螺旋CT三维(3D)重建技术在上气道病变中的临床应用价值。　方法　对36例上气道病变的患者进行轴位螺旋CT扫描,层厚3.0mm,螺距1.0～1.2,分别做气道表面遮盖法(SSD)、表面透视法(RaySum)重建和叠加成像。　结果　SSD图像能清楚显示上气道的正常形态、多方位观察可全景地反映气道表面受压的情况,RaySum能更好地显示狭窄内缘的情况,9例(25%)气道SSD显示正常;SSD图像上显示的肿瘤侵犯范围明显小于轴位和多平面重组(MPR)图像。叠加成像清楚显示肿瘤与邻近结构尤其是血管、气道的关系。　结论　3D重建能立体地显示上气道病变,是轴位和MPR图像的很好补充手段。     

股骨头挖除后螺旋CT三维重建在髋臼粉碎性骨折中的应用

目的 探讨股骨头挖除后螺旋CT三维重建在髋臼粉碎性骨折中的应用价值。资料与方法 对27例经普通X线诊断的髋关节骨折患者,应用螺旋CT扫描获得原始轴面图像,在工作站对兴趣区进行染色显影,通过关节解体技术去除股骨头,然后对髋臼采用多平面重建（MPR）及表面遮盖法（SSD）和容积漫游技术（VRT）三维重建。结果 股骨头挖除后三维重建图像能直观显示髋臼骨折的全貌及关节腔内的游离碎骨片及相互之间的解剖关系。结论 股骨头挖除后SSD和VRT三维重建对外科手术前充分了解髋臼损伤情况、手术方案的制定及内固定器械的选择,均有重要的指导作甩。     

MSCT-3D重建技术在诊断足骨骨折的应用价值

目的探讨螺旋CT3D成像技术在诊断足骨骨折的重组方式与显示复杂骨折的关系。方法 24例患者进行足部螺旋CT扫描,分别用软组织算法B30 s和骨算法B60 s进行薄层重建,在3 D工作站进行多方位MPR和VR重组。结果多层螺旋CT骨算法重建MPR图像骨窗观察能清楚显示足骨骨折,明确骨折线的走行、骨折片的数目、关节面损伤情况及关节腔内骨折片数目、位置;软组织算法重建MPR图像可清楚显示足跟部肌腱和软组织。结论 MSCT三维重组及多平面重组能准确诊断足骨骨折及软组织损伤,为临床诊治提供清晰及立体的影像资料。     

胫骨下端爆裂性关节内骨折的CT三维影像重建

目的探讨三维ＣＴ影像重建在评估胫骨下端爆裂性关节内（Ｐｉｌｏｎ）骨折中的临床意义。方法收集自１９９４年１０月～１９９６年１０月间的Ｐｉｌｏｎ骨折患者１０例。所有患者均接受Ｘ线摄片、ＣＴ扫描和ＣＴ三维影像重建检查。根据以上３种影像学检查的显示，评估骨折的形态、骨折的碎裂程度及移位情况，对Ｐｉｌｏｎ骨折进行分类并选择合适的治疗方法。结果采用ＡＯ系统对骨折分类：Ｃ１型２例，Ｃ２型３例，Ｃ３型５例。４例在Ｘ线平片上显示关节面较完整，仅有轻度移位，但在三维ＣＴ影像和ＣＴ平扫中可见骨关节面不平整，有明显移位。６例患者在ＣＴ影像上可见骨折碎片数目多于平片，并有碎骨块的嵌插。根据三维ＣＴ重建对Ｐｉｌｏｎ骨折不同方位的立体显示，结合Ｘ线征和ＣＴ扫描对１０例患者均采用切开复位内固定，取得良好疗效。结论三维ＣＴ重建能多角度立体显示复杂的涉及关节面的Ｐｉ－ｌｏｎ骨折，弥补了Ｘ线平片和ＣＴ扫描等二维影像在这方面的不足，尤其是在显示关节面碎裂和移位的程度、碎骨块的嵌插及主要骨折线形态上，更是体现了三维影像和ＣＴ扫描的优点，是提高复杂关节内骨折诊断和治疗水平的有效手段之一。