颌面外伤螺旋CT三维成像的评价

目的:评价螺旋CT扫描三维成像对颌面外伤的临床应用价值。材料与方法:使用Somatom Plus S型CT扫描机和随机所附3D软件对25例颌面外伤作三维成像显示。由3位放射诊断医生和4位口腔颌面外科医生用双盲法对每例二维和三维CT图像分别作出评价。结果:三维CT对骨折全貌的显示、骨折块数目测定、移位及骨折分型优于二维CT。结论:螺旋CT扫描获得的容积数据可重建高精度二维和三维图像;三维图像能完整地显示骨折全貌,便于临床医生及时作出诊断、制定手术方案和进行术后评估。     

眼球结构的螺旋CT测量

目的 :利用螺旋CT图像测量建立本地成人眼球结构CT测量正常参考值。方法 :对 2 61例CT扫描原始或重建图像进行测量分析 ,测量指标包括眼球前后径、横径、前房轴深、晶体厚度、玻璃体腔径。用SPSS 11 0统计软件进行各测量指标不同性别 ,年龄组间比较及眼球前后径与前房轴深 ,晶体厚度 ,玻璃体腔径相关性分析。结果 :( 1)CT扫描图像能清晰显示眼球结构 ,边缘清晰。 ( 2 )除晶体厚度外 ,眼球各结构的CT测量值在不同年龄组中差异有显著性 ,男性眼球前后径 ,横径 ,前房轴深 ,玻璃体腔径值分别为 2 5 12± 0 83 ,2 5 2 5± 0 15 ,2 71± 0 5 1,15 77± 0 81;女性为 2 4 48± 0 79,2 4 5 4± 0 84,2 5 4± 0 45 ,15 0 9± 0 93。晶体厚度男女间差异无显著意义 ,但各年龄组间有差异。 70岁前晶体厚度随年龄增长而增厚。玻璃体腔径与眼轴长显著正相关。结论 :首次制定了本地人不同性别眼球各结构的CT测量正常参考值 ,并发现除晶体厚度外 ,眼球各径线测量值男性均大于女性。 70岁前晶体厚度随年龄增长而增厚     

螺旋CT扫描及三维成像在鼻骨骨折中的诊断价值

目的:探讨螺旋CT扫描及三维成像在鼻骨骨折诊断中的应用价值,为鼻骨骨折的治疗提供可靠依据.材料与方法:对48例因面部受到创伤而疑似鼻骨骨折患者采用螺旋CT扫描及三维图像重建,并将检查结果与X线片对比.结果:48例疑似骨折患者中,螺旋CT及三维成像检出鼻骨骨折42例,其余6例CT扫描无异常;X线片检出鼻骨骨折30例,可疑鼻骨骨折4例,其余14例未见异常.结论:螺旋CT扫描及三维成像不仅可以将两侧鼻骨的细微结构清晰显示出来,还能将不同类型的鼻骨骨折的形态、骨折位置、骨折移位程度等清晰显现出来,能有效提高鼻骨骨折诊断的正确率,为鼻骨骨折的医学鉴定及临床治疗具有重要意义.     

螺旋CT扫描三维骨重建在颌面部病变中的临床应用

目的:探讨螺旋CT三维骨重建在颌面部病变中的成像技术及临床应用价值。材料与方法:对42例颌面部行螺旋CT扫描后进行三维骨重建,5例非螺旋CT扫描作为对照。结果:颌面部螺旋CT扫描以层厚2mm~5mm为宜,螺距1为佳,后重建以1mm间隔重组,强调成像技术是影响图像质量的主要因素。三维表面遮盖法重建技术(SSD)能清楚地显示骨折部位、分型、移位情况以及肿瘤整体形态、内部结构,图像立体感强。结论:螺旋CT扫描三维骨重建有利于颌面部骨折、肿瘤的诊断,有利于治疗和手术方案的制订。     

螺旋CT扫描资料建立上颌中切牙三维有限元模型

目的应用螺旋CT扫描资料建立正常人体上颌右侧中切牙三维有限元模型，为今后该部位进一步有限元分析奠定基础。方法选取一名上颌牙列完整，个别正常[牙合]，无显著口腔疾患的13岁女性作为测试对象，应用多层螺旋CT机（GE LightSpeed 16）扫描全头颅，应用有限元法分析软件（ALGOR8．0）建立上颌右侧中切牙三维有限元模型。结果建立右上中切牙及牙周膜的三维有限元模型。该模型共有5379个节点，4964个六面体单元。结论建立了右上中切牙及牙周膜的三维有限元模型，可用于相应的应力一应变分析。     

腹部CT及MRI图像融合配准在临床中的应用

目的：探索在PC平台上实现腹部CT及MRI图像非刚性融合配准，讨论其为临床提供新的诊断信息的应用价值。方法：根据最大互信息原理，对40例患者（男25例，女15例）腹部病变的CT及MRI图像进行融合，再根据图像信息主次性形成两类侧重点不同的融合配准图像。结果：在40例CT和MRI图像（其中有3例CT或MRI图像人为的造成部分缺失）融合中，能够在一幅图像上图像信息相互补充的有37例（人为造成部分缺失的3例顺利融合），比单纯地观察CT或MRI图像更能明确判断病变发展趋势的有30例，手术证实的15例，但有3例图像融合后无明显优越性。结论：微机实现腹部CT及MRI这两种不同来源的多模态图像非刚性融合配准，可为临床医生明确诊断、设计手术、放疗方案提供有利信息；病灶显示更直观，方便了临床医生观察。在融合算法上，最大互信息法几乎可以用在任何不同模式图像的配准，特别是当其中一个图像的数据部分缺损时也能得到很好的配准效果。     

SPECT/CT图像配准测试方法

目的 提出SPECT/CT一体机中SPECT和CT图像配准精度的测试方法。方法 试验模体由立方体构形的8个点源构成,点源由放射性同位素和碘对比剂制备,在SPECT和CT上均可清晰成像,模体构形和尺寸可代表典型的临床应用条件。首先选用具有临床代表性的实验条件和参数,对模体分别行SPECT和CT成像。对图像分别进行分析,得到点源空间坐标,计算配准精度;以点源最大值像素点为中心,得到3个坐标方向的一维分布,分别计算分布重心作为对应方向的坐标值。结果 本文提出的方法在GE和Philips的主流SPECT/CT产品上进行验证,点源都可在SPECT和CT图像中完整成像,测试和分析方法的精度达0.1 mm以上。结论 该实验方法可为SPECT/CT产品性能评估和质量控制提供方法基础。     

多层螺旋CT扫描结合三维成像在输尿管梗阻诊断中的意义

目的比较B超、IVU以及多层螺旋CT三维重建技术在临床诊断输尿管梗阻上差异及三种方法在输尿管梗阻诊断中的意义。方法以我院2009年12月～2012年1月收治疗的41例输尿管梗阻患者为研究对象,对患者的临床资料进行回顾性分析。结果定位诊断符合率组间比较,多层螺旋CT三维重建诊断的符合率明显高于B超和IVU诊断的符合率,且组间比较差异具有统计学意义,P均<0.05;定性诊断符合率组间比较,多层螺旋CT三维重建诊断的符合率明显高于B超和IVU诊断的符合率,且组间比较差异具有统计学意义。结论在临床诊断输尿管梗阻的过程中,与B超、IVU等技术相比较,采用多层螺旋CT三维重建技术进行诊断的临床效果显著,是临床诊断输尿管梗阻的可靠选择。     

三维多模态医学图像自动配准方法研究

提出一种综合应用图像分割与互信息的医学图像自动配准方法.首先采用门限法和数学形态学方法进行预处理,再用k-means方法进行分割,之后采用基于互信息的Powell优化方法配准.将该方法用于磁共振图像(MRI)和正电子发射断层扫描(PET)临床医学图像配准,得到较满意的效果.     

64排螺旋CT泌尿系三维成像患者的护理

目的 探讨护理工作在64排螺旋CT泌尿系三维成像(MSCTU)中的价值.方法 240例患者应用64排螺旋CT进行泌尿系三维成像检查,检查前询问病史及碘过敏史,关注患者的心理状态,做好碘预试验;检查中认真观察患者,对可能出现的任何不良反应进行预判,并制订相应的措施;检查后对症处理出现的各种情况,并做好护理指导.结果 239例患者顺利完成检查,1例在扫描过程中出现药物外渗,扫描失败,经过重新扫描,获得满意图像.结论 利用64排螺旋CT行泌尿系三维成像检查,作为一种无创伤、费用相对较低、安全性高的检查技术,护理操作应贯穿检查的每一步.有效的护理措施直接影响检查结果的准确性,熟练的护理操作及耐心细致的心理护理是MSCTU检查中的重要环节.     

Intra-subject elastic registration of 3D ultrasound images

3D registration of ultrasound images is an important and fast-growing research area with various medical applications, such as image-guided radiotherapy and surgery. However, this registration process remains extremely challenging due to the deformation of soft tissue and the existence of speckles in these images. This paper presents a technique for intra-subject, intra-modality elastic registration of 3D ultrasound images. Using the general concept of attribute vectors, we define the corresponding voxels in the fixed and moving images. Our method does not require presegmentation and does not employ any numerical optimization procedure. As the computational requirements are minimal, the method has potential use in real-time applications. The technique is implemented and tested on 3D ultrasound images of human liver, captured by a 3D ultrasound transducer. The results show that the method is sufficiently accurate and robust even in cases where artifacts such as shadows exist in the ultrasound data.     

Piecewise-diffeomorphic image registration: Application to the motion estimation between 3D CT lung images with sliding conditions

In this paper, we propose a new strategy for modelling sliding conditions when registering 3D images in a piecewise-diffeomorphic framework. More specifically, our main contribution is the development of a mathematical formalism to perform Large Deformation Diffeomorphic Metric Mapping registration with sliding conditions. We also show how to adapt this formalism to the LogDemons diffeomorphic registration framework. We finally show how to apply this strategy to estimate the respiratory motion between 3D CT pulmonary images. Quantitative tests are performed on 2D and 3D synthetic images, as well as on real 3D lung images from the MICCAI EMPIRE10 challenge. Results show that our strategy estimates accurate mappings of entire 3D thoracic image volumes that exhibit a sliding motion, as opposed to conventional registration methods which are not capable of capturing discontinuous deformations at the thoracic cage boundary. They also show that although the deformations are not smooth across the location of sliding conditions, they are almost always invertible in the whole image domain. This would be helpful for radiotherapy planning and delivery.     

螺旋CT三维重建方法在颞骨影像学的对比研究

目的:探讨成人颞骨螺旋CT三维重建技术。方法:对正常30耳,慢性化脓性中耳炎41耳行螺旋CT检查,把扫描所得的容积数据进行三维重建,包括最大密度投影法(MIP)、最小密度投影法(MinIP)、仿真内窥镜法(CTVE)和容积再现法(VR)。结果:MIP、MinIP、CTVE和VR可以从不同的方面对颞骨内结构进行三维显示。结论:对于颞骨内结构的显示,VR是目前较好的三维重建方法。     

Automated 3-D registration of MR and CT images of the head

This paper discusses the application of voxel similarity measures in the automated registration of clinically acquired MR and CT data of the head. We describe a novel single-start multi-resolution approach to the optimization of these measures, and the issues involved in applying this to data having a range of different fields of view and sampling resolution. We compare four proposed measures of voxel similarity using the same optimization scheme when presented with 10 pairs of images with a range of initial misregistrations. The registration estimates are compared with those provided by manual point-based registration and evaluated by visual inspection to give an assessment of the robustness and accuracy of the different measures. One full-volume CT image set is used to investigate the performance of each measure when used to align truncated images from different regions in the head. The soft tissue correlation and mutual information measures were found to provide the most robust measures of misregistration, providing results comparable to or better than those from manual point-based registration for all but the most truncated image volumes.     

Nonrigid registration of 3D tensor medical data

New medical imaging modalities offering multi-valued data, such as phase contrast MRA and diffusion tensor MRI, require general representations for the development of automated algorithms. In this paper we propose a unified framework for the registration of medical volumetric multi-valued data using local matching. The paper extends the usual concept of similarity between two pieces of data to be matched, commonly used with scalar (intensity) data, to the general tensor case. Our approach to registration is based on a multiresolution scheme, where the deformation field estimated in a coarser level is propagated to provide an initial deformation in the next finer one. In each level, local matching of areas with a high degree of local structure and subsequent interpolation are performed. Consequently, we provide an algorithm to assess the amount of structure in generic multi-valued data by means of gradient and correlation computations. The interpolation step is carried out by means of the Kriging estimator, which provides a novel framework for the interpolation of sparse vector fields in medical applications. The feasibility of the approach is illustrated by results on synthetic and clinical data.     

多层螺旋CT在颌面部骨折的诊断及临床应用价值

目的探讨多层螺旋CT在颌面部骨折中的诊断及治疗指导价值。方法对20例颌面部骨折患者行16层螺旋CT扫描后。利用工作站进行图像后处理，选用多种软件技术，多平面重建（MPR）、三维表面遮盖显示（3D～SSD）及容积再现法（VR）等重组观察．并与CT横断图像进行比较。结果16层螺旋CTMPR成像清晰显示了所有的颌面部骨折及周围软组织的损伤情况，特别对细微骨折及深部骨折显示优于3D—SSD、VR成像。而3D—SSD、VR成像立体可直观展现骨折的部位，骨折线的走行，骨质的碎裂程度及移位情况。结论16层螺旋CTMPR结合3D—SSD、VR成像能够明确诊断颌面部骨折，并为其临床治疗提供依据。     

CT三维重建在口腔颌面部疾患中的应用

目的:探讨螺旋CT三维重建对口腔颌面部疾病诊治的临床应用价值。方法:对17例患者进行螺旋CT扫描,层厚2mm,应用表面遮盖显示法和多层面重建技术进行三维图像重建,用不同的旋转轴观察不同的三维病变图像。结果:螺旋CT三维重建能清楚显示病变的立体解剖图像及其与周围结构的关系,为手术设计和指导治疗提供了客观依据。结论:螺旋CT三维重建有利于明确病变的范围及与周围结构的关系,有利于手术方案的设计和实施。     

3D spatial compounding of ultrasound images using image-based nonrigid registration

Medical ultrasound images are often distorted enough to significantly limit resolution during compounding (i.e., summation of images from multiple views). A new, volumetric image registration technique has been used successfully to enable high spatial resolution in three-dimensional (3D) spatial compounding of ultrasound images. Volumetric ultrasound data were acquired by scanning a linear matrix array probe in the elevational direction in a focal lesion phantom and in a breast in vivo. To obtain partly uncorrelated views, the volume of interest was scanned at five different transducer tilt angles separated by 4° to 6°. Pairs of separate views were registered by an automatic procedure based on a mutual information metric, using global full affine and thin-plate spline warping transformations. Registration accuracy was analyzed automatically in the phantom data, and manually in vivo, yielding average registration errors of 0.31 mm and 0.65 mm, respectively. In the vicinity of the warping control points, registrations obtained with warping transformations were significantly more accurate than full affine registrations. Compounded images displayed the expected reduction in speckle noise and increase in contrast-to-noise ratio (CNR), as well as better delineation of connective tissues and reduced shadowing. Compounding also revealed some apparent low contrast lobulations that were not visible in the single-sweep images. Given expected algorithmic and hardware enhancements, nonrigid, image-based registration shows great promise for reducing tissue motion and refraction artifacts in 3D spatial compounding.     

Intensity-based registration of freehand 3D ultrasound and CT-scan images of the kidney

Objectives This paper presents a method to register a pre-operative computed-tomography (CT) volume to a sparse set of intra-operative ultra-sound (US) slices. In the context of percutaneous renal puncture, the aim is to transfer planning information to an intra-operative coordinate system. Materials and methods The spatial position of the US slices is measured by optically localizing a calibrated probe. Assuming the reproducibility of kidney motion during breathing, and no deformation of the organ, the method consists in optimizing a rigid 6 degree of freedom transform by evaluating at each step the similarity between the set of US images and the CT volume. The correlation between CT and US images being naturally rather poor, the images were preprocessed in order to increase their similarity. Among the similarity measures formerly studied in the context of medical image registration, correlation ratio turned out to be one of the most accurate and appropriate, particularly with the chosen non-derivative minimization scheme, namely Powell-Brent’s. The resulting matching transforms are compared to a standard rigid surface registration involving segmentation, regarding both accuracy and repeatability. Results The obtained results are presented and discussed.     

多层螺旋CT三维成像在血管病变中的临床应用

目的 探讨多层螺旋CT三维成像在血管病变中的临床应用价值。方法 对27例颈部、体部及四肢血管病变的患行多层螺旋CT平行及增强扫描，以多平面重组（MPR）、表面遮盖法（SSD）、实时3D重建（RT－3D）、血管CT仿真内镜（CTVE）等多种方式重建。结果 MPR能保留有助于定性诊断的密度CT征象，多方位地显示附壁血栓、真假腔、充盈缺损等，但缺乏病变与周围解剖结构的立体观；SSD均能直观地显示血管病变的全貌，以及病变与分支血管的关系等，但不能显示管腔内的情况；RT－3D可清楚显示血管壁的钙化、测量各径线参数以及多角度观察病变，其图像优于其他方法的重建图像；CTVE可清晰显示血管狭窄、真假腔、内膜片及钙化斑块的形态。结论 综合应用多层螺旋CT的各种重建技术诊断血管性疾病，为临床提供了一种安全可靠的诊断手段。