CT和MRI图像融合三维重建颞下颌关节的研究

目的利用CT和MRI扫描图像,探讨采用模型融合技术对颞下颌关节（TMJ）软硬组织进行三维重建的方法,为TMJ生物力学研究及其临床分析提供依据。方法选择1例健康青年男性志愿者,在其双侧TMJ区和颏部共放置12个人造球形标记,经CT和MRI扫描,获取含有所有球形标记的TMJ医学图像,分别采用CT和MRI两套数据建立TMJ软硬组织的三维几何模型。基于人造球形标记在三维空间上配准,对TMJ软硬组织进行三维重建。结果建立了具有良好几何相似性的TMJ三维几何模型,包括关节盘、关节窝、下颌骨和下牙列。TMJ三维几何模型的建立方法简便快捷,模型逼真,解剖结构清楚,能较真实地反映TMJ各结构的空间位置关系。结论利用CT和MRI医学图像融合技术,基于人造球形标记的配准过程进行TMJ三维重建,所建立的模型具有良好的几何相似性。在三维水平上进行图像的融合,具有定位精确,配准过程简单等特点,能真实、合理地对TMJ软硬组织进行三维重建。     

CT/MRI图像整合建立半月神经节射频手术的导航界面

目的:建立CT/MRI配准和融合基础上的卵圆孔与半月神经节共存的手术界面,实现半月神经节与穿刺针关系的可视化。方法:将10例三叉神经痛患者的增强3d Fiesta序列的MRI数据和头颅CT数据导入surgView-RFT电磁导航系统,增强3d Fiesta上分割出半月神经节图像,单独保存。头颅增强3dFiesta和CT以鼻根点、双侧髁突外侧嵴点3点进行线性配准,在CT/MRI融合基础上二次融合半月神经节图像,建立卵圆孔与半月神经节共存的手术界面。结果:10例患者的20侧半月神经节均在增强3d Fiesta上被分割成像。经图像融合后卵圆孔与半月神经节的位置关系如下:冠状位、矢状位上半月神经节不位于卵圆孔开口区的为2/20,半月神经节位于卵圆孔开口区的为18/20。结论:CT/MRI整体配准和融合基础上的卵圆孔与半月神经节共存的导航手术界面,可以排除非靶组织的干扰,使靶点和穿刺针的关系更加简单明了,便于应用者识别,同时为实现分支选择性射频温控热凝术奠定基础。     

低剂量 CT 扫描重建颌面部软硬组织三维模型的剂量研究

目的：评价 CT 扫描剂量对重建颌面部软硬组织三维模型的影响,为低剂量 CT（LDCT）在颜面赝复体 CAD/CAM技术中的应用提供依据。方法：采用 Lightspeed 16排螺旋 CT 机对成人尸头标本,分别进行常规参数（280 mA）和低剂量参数（200、150、100、50、35、25、15、5 mA）扫描,应用 Mimics 10．01软件重建软硬组织三维模型;利用 Geomagic 11．0软件进行三维比较,评价不同扫描参数下重建软硬组织三维模型表面形态的差异。结果：随着管电流的降低,模型表面逐渐变粗糙,与280 mA 相比,降至35 mA 时模型表面仍较光顺,但降至25 mA 以下时表面粗糙,难以确定其准确形态;模型配准后表面形态检测得出相同的结果。结论：低剂量 CT（35 mA）扫描可用于颌面部软硬组织三维模型的重建。     

计算机导航技术在颌骨骨纤维异常增殖症手术中的应用

目的:探讨计算机导航技术在颌骨骨纤维异常增殖症手术中的应用价值.方法:纳入14例颌面部骨纤维异常增殖症患者,先将患者的术前CT数据导入计算机导航系统中,根据颌骨镜像原理进行术前设计及三维手术模拟,确定骨切除位置及范围.术中,根据病变部位及手术范围可将参考架置于患者前额或是下颌骨颏部.完成注册与配准,使手术视野和导航显示屏上的虚拟图像完全匹配.结果:面部的解剖结构与三维重建模型完全吻合,术中顺利完成实时导航.手术器械可实现空间定位,能够明确其与手术区域解剖结构的位置关系,手术具有高度的精确性与安全性.术后疗效的评估是通过术前计划和术后CT重建影像相融合得到的,1～3年的随访中没有发现并发症.结论:计算机导航系统在提高颌面部骨纤维异常增殖症的安全性与准确性方面具有较好的应用价值.     

颌面专用CT下颌骨检查技术

目的：研究颌面专用CT（QR-DVT 9000 NEWTOM）下颌骨检查技术的建立方法及技术要点,观察颌面专用CT下颌骨检查技术,在下颌骨X线检查中的优势.方法：对下颌骨疾病患者进行颌面专用CT扫描和重建成像,对其重建轴位影像进行曲面、矢状位、冠状位以及3D影像的后处理,并与常规X线片对比分析.结果：颌面专用CT下颌骨检查技术优于下颌骨常规X线检查,分别以水平位、曲面、矢状位、冠状位以及3D等多方位影像显示下颌骨的信息.结论：颌面专用CT下颌骨检查技术,在下颌骨的X线检查中有着明显的优势,并能够有效地指导临床手术.     

3D整合牙颌模型在无托槽隐形治器设计中的应用

目的 探讨将3D整合牙颌模型应用于无托槽隐形矫治器设计,以便精确控制牙根在颌骨中的移动.方法 将基于锥形束计算机断层扫描( CBCT)的牙颌模型和基于机构光扫描的牙冠模型自动配准,建立能精确显示牙列、咬合、牙根及颌骨的3D整合牙颌模型.在3D整合牙颌模型上进行模拟排牙和虚拟矫治,然后应用激光快速成型技术制作无托槽隐形...     

配准法建立上中切牙全瓷冠的三维有限元模型

目的利用配准法建立上中切牙全瓷冠的三维有限元模型。方法运用3DCaMega分别扫描预备前后的KaVo教学用上颌中切牙,获取点云数据,再用Geomagic软件数据预处理,重建网格曲面,根据标志块将二者进行配准缝合,获得全瓷冠的三维实体数值模型。再导入Marc软件,建立上中切牙全瓷冠的三维有限元模型,并对模型进行模拟加载力学分析。结果全瓷冠的三维有限元模型与实体具有高度的几何相似性与力学相似性。结论利用配准法建立全瓷冠三维有限元模型,可避免扫描盲区的影响。     

颅面复合体三维几何模型的精确建立

目的:探讨利用螺旋CT原始数据建立包含牙列的颅面复合体三维几何模型的数字化方法,建立一个高精度的包含牙列的颅面复合体三维实体模型。方法:采用多排螺旋CT对恒牙早期骨性安氏Ⅲ类患者行常规头部平扫及三维数字影像重建,利用原始DICOM数据,自编程序,以及ANSYS和Solidw orks软件,建立颅面复合体三维几何模型。结果:建立完整的颅面复合体三维实体几何模型,包含22块骨骼和28颗牙齿。探索出一条适用于活体的颅面复合体三维几何模型的建模方法。结论:应用螺旋CT薄层扫描,ANSYS和Solidw orks软件,建立包含牙列的颅面复合体三维几何模型是一种准确、有效的方法。     

个性化重建板辅助游离腓骨重建上颌骨半侧缺损的优化设计

目的: 利用CAD/CAM以及3D打印技术体外辅助游离腓骨瓣重建上颌骨半侧缺损。方法: 利用CAD/CAM建立游离腓骨瓣重建上颌骨半侧缺损的三维模型,设计个性化重建板、截骨导板辅助重建完成,通过3D打印技术生成术前模型、截骨导板以及重建板,模型外科模拟手术。采用SPSS18.0软件包对数据进行统计学分析。结果: 快速建立了3段式游离腓骨重建上颌骨缺损的数字化模型,并设计生成原发灶截骨导板和重建辅助个性化重建板。定点测量显示,模型外科模拟重建精度与计算机模拟无显著差异（P>0.05）。结论: 优化设计的辅助措施和个性化重建板可以增加游离腓骨重建上颌骨缺损的准确性,有助于临床上精确外科重建。     

根据CT扫描数据及印模三维重建牙列数字模型精度的初步研究

目的:评价根据CT扫描数据和牙列印模重建牙列数字模型的精度.方法:以OKIO-V-100三维光学扫描系统扫描猴牙列标本获取标准模型;根据螺旋CT、锥柬CT扫描数据重建颌骨及牙列三维数字模型;制取猴牙列标本印模,灌制石膏模型,通过OKIO-V-100三维光学扫描系统扫描重建牙列形态.分别将CT扫描重建的数字图像、石膏模型...     

应用螺旋CT三维重建颌面部软组织的研究

目的：评价螺旋CT在颌面部软组织重建中的价值。方法：对1例右耳缺损患者的头部进行螺旋CT扫描．扫描数据以DICOM格式储存。在诊断工作站上以SSD法对图像进行重建。结果：螺旋CT能一次快速精确完成整个头部的扫描与重建,面部软组织、器官重建图像清晰,但瞳孔位置不能显示。结论：对于头面部除瞳孔以外的软组织三维重建,可选择螺旋CT三维重建方式。     

The accuracy of matching three-dimensional photographs with skin surfaces derived from cone-beam computed tomography

The state-of-the-art diagnostic tools in oral and maxillofacial surgery and preoperative orthodontic treatment are mainly two-dimensional, and consequently reveal limitations in describing the three-dimensional (3D) structures of a patient's face. New 3D imaging techniques, such as 3D stereophotogrammetry (3D photograph) and cone-beam computed tomography (CBCT), have been introduced. Image fusion, i.e. registration of a 3D photograph upon a CBCT, results in an accurate and photorealistic digital 3D data set of a patient's face. The purpose of this study was to determine the accuracy of three different matching procedures. For 15 individuals the textured skin surface (3D photograph) and untextured skin surface (CBCT) were matched by two observers using three different methods to determine the accuracy of registration. The registration error was computed as the difference (mm) between all points of both surfaces. The registration errors were relatively large at the lateral neck, mouth and around the eyes. After exclusion of artefact regions from the matching process, 90% of the error was within+/-1.5 mm. The remaining error was probably caused by differences in head positioning, different facial expressions and artefacts during image acquisition. In conclusion, the 3D data set provides an accurate and photorealistic digital 3D representation of a patient's face.     

Three-dimensional magnetic resonance image of the mandible and masticatory muscles in a case of juvenile chronic arthritis treated with the Herbst appliance

The present report documents, in a case of juvenile chronic arthritis (JCA) with mandibular retrognathia, three-dimensional (3D) changes in the mandible and the relationship between the mandible and the masticatory muscles resulting from treatment with the Herbst appliance after cessation of growth. Magnetic resonance scanning of the whole head was carried out before and after treatment. The mandible, the masseter, and the medial and lateral pterygoid muscles were segmented bilaterally and reconstructed in 3D for both stages. Superimposition of the datasets was carried out according to anatomical structures in the brain (cranial base). Mandibular superimposition was performed according to the mandibular symphysis and the lower mandibular border. The mandible moved forward and downward relative to the anterior cranial base. In addition, bone apposition was observed at the superior and posterior surfaces of both mandibular condyles and at the roof of the glenoid fossa. The masticatory muscles remained relatively stable in position in relation to the anterior cranial base. To our knowledge, such information in JCA patients has not previously been published in the literature. Using magnetic resonance imaging (MRI), it was possible to gain improved insight into the 3D morphology including soft tissues without the overlap of the surrounding tissues observed in the conventional radiographs. Accordingly, it is suggested that 3D magnetic resonance analysis is a more useful method for the follow-up of the JCA patients than radiographic techniques.     

数字化及3D打印联合内镜辅助技术治疗12例颧骨颧弓骨折效果评价

目的:探讨数字化及3D打印联合内镜辅助技术在颧骨颧弓骨折治疗中的应用效果。方法:选择2020年12月—2021年9月于蚌埠医学院第一附属医院行手术治疗的12例单侧颧骨颧弓骨折患者纳入研究。所有患者术前均行全头颅薄层CT检查,利用镜像反求原理对骨折部位进行模拟复位,并打印复位后的骨折模型,在模型上进行钛板预弯。术中在内镜辅助下采用前庭沟切口结合耳屏前切口对骨折断端进行解剖复位。术后所有患者均再次行全头颅薄层CT检查,将术后重建的三维模型数据与术前模拟复位的三维模型数据进行光谱融合色差对比分析,评价术后效果。结果:12例患者手术顺利,术后面部外形及功能恢复良好,无明显并发症,面部皮肤瘢痕隐蔽。术后CT与术前模拟设计光谱融合色差对比分析最大上偏差为2.998 7 mm,最大下偏差为-2.998 6 mm,平均上偏差为（0.243 0±0.025 0）mm,平均下偏差为（-0.310 0± 0.180 0）mm。结论:数字化及3D打印联合内镜辅助技术在直视下对骨折部位进行解剖复位,有助于提高骨折复位的精准度,减少术中组织损伤、术后并发症的发生,术后瘢痕隐蔽,具有良好的美观效果。     

牙种植动态导航配准方式对配准精度的影响

牙种植动态导航系统(DNS)是一种利用精确的红外定位技术,通过对三维数字影像的可视化操作,最终实现三维影像和实际解剖位置的精确融合,实时追踪手术器械的牙种植手术辅助系统,适用于牙种植手术的术前规划和精确的术中引导。影响DNS精确性的关键因素是实际术区解剖结构与其虚拟三维数字影像的精确配准,而不同配准方式的适应证、配准特点和配准精度等各不相同。本文对临床所应用的配准方式,包括骨标记物配准、咬合夹板配准、U型管配准、面部框架式配准、解剖标志点配准及无标记点配准进行介绍,并对影响配准误差的因素进行总结,以便临床医生更好地了解不同配准方式的特点,减少配准误差,达到精准种植的效果。     

多平面辅助定位法提高颅颌面三维CT测量准确性的研究

目的:建立一种较准确的三维头影测量定点方法,为面部不对称畸形的临床三维测量打下基础。方法:采用螺旋CT系统,对10例面部不对称畸形患者进行全头颅扫描,并进行CT影像三维重建,描绘测量16个相关解剖标志点。采用SAS8.02软件进行直线相关性和零截距直线回归分析,得到各标志点三维坐标的直线相关系数和零截距直线回归系数。结果:16个标志点的48个三维坐标数据的直线相关系数r、零截距直线回归系数b都在0.99000～1.01000以内。结论:本研究采用的三维测量方法具有较高的准确性和可重复性。该套定位要求及标志点,可以为面部不对称患者的硬组织形态特征改变研究提供参考。     

Validation of new soft tissue software in orthognathic surgery planning

This study tests computer imaging software (SurgiCase-CMF^®, Materialise) that enables surgeons to perform virtual orthognathic surgical planning using a three dimensional (3D) utility that previews the final shape of hard and soft tissues. It includes a soft tissue simulation module that has created images of soft tissues altered through bimaxillary orthognathic surgery to correct facial deformities. Cephalometric radiographs and CT scans were taken of each patient before and after surgery. The surgical planning system consists of four stages: CT data reconstruction; 3D model generation of facial hard and soft tissue; different virtual surgical planning and simulation modes; and various preoperative previews of the soft tissues. Surgical planning and simulation is based on a 3D CT reconstructed bone model and soft tissue image generation is based on physical algorithms. The software rapidly follows clinical options to generate a series of simulations and soft tissue models; to avoid TMJ functional problems, pre-surgical plans were evaluated by an orthodontist. Comparing simulation results with postoperative CT data, the reliability of the soft tissues preview was >91%. SurgiCase^® software can provide a realistic, accurate forecast of the patient's facial appearance after surgery.     

Towards building a photo-realistic virtual human face for craniomaxillofacial diagnosis and treatment planning

The aim of this investigation was to assess the feasibility of building a virtual human face digitally by superimposing a photo-realistic three-dimensional (3D) soft-tissue surface on bone in the correct relationship and evaluating the registration errors associated with this method. The 3D soft-tissue surface of the face was captured using a fast stereophotogrammetry method and the underlying bone was recorded using a 3D computed tomography (CT) scanner. Using the Procrustes registration method, the outer surface of the 3D CT scan and the photo-realistic soft-tissue surfaces were merged into a single Virtual Reality Modelling Language (VRML) file and displayed using a standard VRML viewer. Quantitative measurements of registration errors were calculated in the reconstructed human head models using the signed closest point distance from the photo-realistic skin surface to the transformed CT skin surface. The registration errors between most parts of the aligned surfaces were within +/-1.5mm. The errors were relatively large around the eyebrows, eyelids and cheeks. Simultaneous recording of the face and skull may reduce this error.