锥形束CT转化头颅侧位片与传统头颅侧位片测量一致性研究

目的：评价锥形束计算机断层扫描( cone-beam computed tomography, CBCT)转化的头颅侧位片与传统头颅侧位片测量结果的一致性。方法对31位正畸治疗后患者进行CBCT扫描,同时拍摄传统头颅侧位片作为对照。利用Dolphing Imaging 11．5 Premium 软件按照统一条件将CBCT转化为头颅侧位片。选择29个标志点,由同一位测量者在两种头颅侧位片分别测量每位病人的29个参数值,间隔1周后再随机抽取10名病人重复测量上述29个参数。采用组内相关系数( ICC)评价操作者的测量信度,并采用配对t检验分析两种头颅侧位片测量结果的一致性。结果82．8%(24/29)的转化头颅侧位片测量项目ICC>0．9,79．3%(23/29)的传统头颅侧位片测量项目ICC>0．9,两种头颅侧位片的ICC无统计学差异(t=0．762,P=0．449)。骨性标志中ANS-Me、S-Go和N-Me的传统头颅侧位片测量值明显高于转化头颅侧位片的测量值;牙性标志中L1-NB和L1-NB的传统头颅侧位片测量值也明显高于转化头颅侧位片测量值;而软组织标志中,软组织面凸角值的转化头颅侧位片测量值明显高于传统头颅侧位片测量值。统计学分析结果提示上述差异均具有显著性意义。结论转化头颅侧位片和传统头颅侧位片两种头影测量方法均具有较高的组内相关系数,但是两种方法在某些标志点上的测量值之间存在差异,在利用头影测量结果进行口腔正畸疗效评价时需要慎重。     

无牙颌不同颌位颏前点变化规律的头颅侧位片定位研究

目的：探讨无牙颌不同颌位时颌前点的变化规律，为无牙颌修复时He位的确定提供根据。方法：选取临床上22例无牙颌He重建的患，在五组颌位上拍摄头颅侧位片，分别测量颏前点到圆点的距离和SNPg角的数值及在正中关系位时SN—GoGn角的数值。结果：各组颏前点到圆点的距离无显差异。无牙颌建He位与正常He人He位无显差异，从无牙颌位至最大张口位下颌突度的变化差异显。结论：下颌颏部从无牙颌位到最大张口位有其自身的运动规律，颏前点的运动轨迹为围绕某一点旋转的弧形。无牙颌He重建时协调的长正中关系位就位于此弧线上。从无牙颌位到最大张口位，下颌颏部突度的变化成不连续性减小。从无牙颌位到正中关系位下颌突度减小；从3／4张口位到最大张口位下颌突度无变化。     

间接与直接数字式头颅侧位片影像质量的对比性研究

目的：对间接与直接方式数字式Ｘ线影像质量及图像处理前后,数字式Ｘ线影像质量进行对比性研究。方法：以主观评价指标为手段,采用盲法设计对间接与直接方式获得的２８组数字式Ｘ线影像的质量进行了对比。结果：获得了各种测试指标的主观评分及排序。结论：同间接方式获得的数字式Ｘ线影像清晰度的评分要高于直接方式获得的数字式Ｘ线影像,图像处理技术在提高间接数字式Ｘ线影像质量上有一定的作用。     

前方牵引治疗后的头颅侧位片分析

大部分Ⅲ类错He畸形的患者表现为上颌骨前后向及垂直向发育不足，笔者应用Fishmam的系统骨龄判断标准(SMA)将患者按骨龄分为三组，所有患者治疗前及治疗结束后均拍摄头颅侧位片，来研究骨性Ⅲ类错He畸形的治疗时机及经上颌扩弓加前方牵引治疗后骨性及牙性变化。     

锥形束CT转化头颅侧位片定点精确性的研究

目的 研究对比锥形束计算机断层扫描（Cone-beam computed tomography,CBCT）转化的头颅侧位片与传统头颅侧位片（Cephalogram,Ceph）的定点精度.方法 对20名需要正畸的患者（男7名,女13名,平均年龄18.8岁）进行锥形束CT扫描,同时拍摄Ceph作为对照.在InvivoDental 5.0软件中按统一条件将CBCT数据转化成头颅侧位片（Cephalogram from CBCT,CCB）.选择23个常用标志点,由三名操作者分别对CCB与Ceph进行定点,间隔进行两次.对CCB与Ceph上的定点误差,以及不同操作者之间的定点误差进行统计分析,采用方差分析与t检验.结果 三名操作者在CCB上定点的精度明显优于Ceph（P＜0.05）,19个定点的精度有8个点的定点误差差异有显著性（P＜0.05）.操作者之间的相关性CCB比Ceph好.操作者自身两次测量值重复性好,相关系数0.99.结论 CCB由于可以选择性生成单侧或双侧头颅侧位片,定点的精度普遍要优于Ceph,尤其是颅底点（Ba）,耳点（P）,眶点（O）,前鼻棘（ANS）点,上齿槽座点（A）,下颌角点（Go）,以及切牙及磨牙根尖点在CCB上的定点更精确.对于一些定点误差较大的点可能是由于在三维空间中点的定义还不明确.     

锥形束CT转化头颅侧位片定点精确性的研究

Objective In this study, we compared the precision of landmark identification using cephalograms from cone-beam computed tomographic (CBCT) volumes and conventional lateral cephalograms (Ceph). Methods Twenty pre-orthodontic patients were radiographed with conventional Ceph and CBCT techniques. CBCT data was uploaded into InvivoDental software 5.0 to generate cephalograms(CCB). Three observers plotted 23 landmarks using computer displays of CCB and Ceph views during separate sessions. Absolute differences between CCB and Ceph of all observers were measured. The absolute difference between each observer was also measured. ANOVA and paired t tests were used to analyze variability differences. Results The difference of landmark identification between CCB and Ceph were significant at P＜0.05 calculations. 8 landmarks variability was statistically greater than Ceph views. The variability of CCB for each observer was consistently greater than in Ceph. The overall correlation of CCB and Ceph measurements was excellent at 0.99.Conclusions The CCB displays of CBCT volume images provide generally more precise identification than Ceph. More precise location of basion, porion, orbitale, ANS, A point, Gonion and tooth apex overcomes the problem of superimposition of these bilateral landmarks seen in Ceph. Greater variability of certain landmarks is probably related to inadequate definition of the landmarks in the third dimension.     

锥形束CT转化头颅侧位片定点精确性的研究

Objective In this study, we compared the precision of landmark identification using cephalograms from cone-beam computed tomographic (CBCT) volumes and conventional lateral cephalograms (Ceph). Methods Twenty pre-orthodontic patients were radiographed with conventional Ceph and CBCT techniques. CBCT data was uploaded into InvivoDental software 5.0 to generate cephalograms(CCB). Three observers plotted 23 landmarks using computer displays of CCB and Ceph views during separate sessions. Absolute differences between CCB and Ceph of all observers were measured. The absolute difference between each observer was also measured. ANOVA and paired t tests were used to analyze variability differences. Results The difference of landmark identification between CCB and Ceph were significant at P＜0.05 calculations. 8 landmarks variability was statistically greater than Ceph views. The variability of CCB for each observer was consistently greater than in Ceph. The overall correlation of CCB and Ceph measurements was excellent at 0.99.Conclusions The CCB displays of CBCT volume images provide generally more precise identification than Ceph. More precise location of basion, porion, orbitale, ANS, A point, Gonion and tooth apex overcomes the problem of superimposition of these bilateral landmarks seen in Ceph. Greater variability of certain landmarks is probably related to inadequate definition of the landmarks in the third dimension.     

2种锥形束CT转化头颅侧位片的定点一致性探讨

目的: 采用2种方式将头颅锥形束CT（cone-beam CT,CBCT）数据转化为头颅侧位片,对比2组定点分析的一致性。方法: 利用Dolphin软件将56例牙列完整患者的头颅CBCT数据转换为侧位片,对照组一次性投照右半侧,实验组分别对右侧6个部位投照,形成组合式侧位片。由1名资深正畸医师对23个常用标志点分别进行描迹,采用SPSS 13.0软件包中的Hotelling T²检验分析2组定点的一致性。结果: 前鼻脊点、后鼻脊点、上切牙根尖点、下切缘点、下切牙根尖点、髁突点的定点差异具有统计学意义（P<0.05）。结论: 组合式侧位片能更清晰地显示所需检测的解剖结构,测量的准确性更优。     

头颅侧位片最佳扫描分辨率的研究

目的 :寻找扫描头颅侧位片时的最佳扫描分辨率。方法 :随机选择 2 0张头颅侧位片 ,每张片子分别以 5种不同的分辨率(72dpi,10 0dpi,15 0dpi,2 0 0dpi,30 0dpi)扫描输入计算机。使用头影测量软件测量每张X光片 ,并比较不同分辨率对测量结果的影响。结果 :5种不同扫描分辨率所得的头影测量结果间差异无显著性。结论 :头颅侧位片扫描时的最佳分辨率为 72dpi。     

X线全颌曲面断层片与X线头颅侧位片相关性的研究

目的：研究X线全颌曲面断层片与头颅侧位片上对应的垂直向角度及线距是否具有相关性。方法：随机选取49名患者同期拍摄的X线全颌曲面断层片与头颅侧位片，测量每位患者两张X线片上对应的垂直向角度及线距，对测量结果进行统计分析。结果：X线全颌曲面断层片与头颅侧位片上的FH-MP角(下颌平面角)Go-FH距对Me-FH距比值呈高度线性相关；FH-PP角、FH-OP角(He平面角)呈弱相关，X线全颌曲面断层片上Go-FH对Me-FH距的比值与头颅侧位片上的Co-S距对Me-N距的比值(前后面高比)呈高度线性相关。结论：可通过X线全颌曲面断层片对垂直骨面型进行诊断。     

Cephalometric digitization: A determination of the minimum scanner settings necessary for precise landmark identification.

This study focused on the interpretation of scanned cephalometric images after the digitization of the original analog film, with a variety of standard scanner settings. The purpose was to determine the minimum allowable resolution, grayscale, and color settings of these digital images, without compromising the precision of orthodontic landmark identification. Forty-nine orthodontic residents and faculty at Saint Louis University identified 13 landmarks in 3 separate trials on either an original lateral cephalogram or 1 of 6 digitized radiographic images. They also subjectively assessed the quality of the image. Ability to identify landmarks did not differ significantly among the groups tested. Conversely, opinions of image quality differed significantly among the groups. Participants found the quality of the grayscale images without color to be poorer than that of the original film but could detect differences only at resolution extremes. Prediction of ability to identify landmarks was substantially greater for higher resolution images. In conclusion, the scanner settings used in the digitization of a cephalometric film did not matter significantly when standard settings were used. In addition, subjective opinion of image quality was predictive of how precisely landmarks were identified when the resolution was relatively high.     

计算机辅助Delaire头影测量分析方法的研究

目的实现Delaire头影测量分析法在WinCeph8.0软件中的计算机辅助分析,减少该法手工测量过于复杂、工作量大的不足。方法基于Delaire头影测量分析法的原理和WinCeph8.0中的编程模块,通过自定义标记点、辅助线,编写相关测量、分析程序,构建计算机辅助Delaire头影测量分析法,并对Delaire计算机辅助测量和手工测量结果做配对t检验和离散性分析。结果计算机辅助Delaire头影测量分析法能方便、快速、准确地进行标记点、辅助线描记,自动完成数据的测量计算,显示分析结果。统计分析显示Delaire计算机辅助测量较手工测量准确性更高,适合临床应用。结论本研究为Delaire头影测量分析法提供了一个方便、快捷、准确的计算机辅助测量分析平台,具有较好的临床推广价值。     

Reproducibility of measurements in tablet-assisted,PC-aided,and manual cephalometric analysis

Objective:To assess the reproducibility of cephalometric measurements performed with software for a tablet, with a program for personal computers (PCs), and manually.Materials and Methods:The pretreatment lateral cephalograms of 20 patients that were acquired using the same digital cephalometer were collected. Tracings were performed with NemoCeph for Windows (Nemotec), with SmileCeph for iPad (Glace Software), and by hand. Landmark identification was carried out with a mouse-driven cursor using NemoCeph and with a stylus pen on the iPad screen using SmileCeph. Hand tracings were performed on printouts of the cephalograms, using a 0.3-mm 2H pencil and a protractor. Cephalometric landmarks and linear and angular measurements were recorded. All the tracings were done by the same investigator. To evaluate reproducibility, for each cephalometric measurement the agreement between the value derived from NemoCeph, that given by SmileCeph and that measured manually was assessed with the intraclass correlation coefficient (ICC). Agreement was rated as low for an ICC ≤0.75, and an ICC > 0.75 was considered indicative of good agreement. Also, differences in measurements between each software and manual tracing were statistically evaluated (P < .05).Results:All the measurements had ICC >0.8, indicative of a high agreement among the tracing methods. Relatively lower ICCs occurred for linear measurements related to the occlusal plane and to N perpendicular to the Frankfurt plane. Differences in measurements between both software programs and hand tracing were not statistically significant for any of the cephalometric parameters.Conclusion:Tablet-assisted, PC-aided, and manual cephalometric tracings showed good agreement.     

常用头影测量软件重叠技术的准确性研究

目的 分析常用头影测量软件重叠技术的准确性.方法 选取2010—2018年就诊于哈尔滨医科大学附属第一医院口腔正畸科的患者80例,分为青少年组与成年组,每组各40例.取每例样本矫治前后头颅侧位片,采用Bj?rk结构重叠法与常用头影测量软件重叠法进行上下颌重叠分析,计算两种重叠方法矫治前后分别得出的上下颌中切牙以及上下颌...     

下颌第三磨牙近中阻生相关因素的头影测量分析

目的探讨成人下颌第三磨牙(M3)近中向阻生或萌出的机制及其与颌骨发育的关系。方法选取72例正畸患者为研究对象,术前拍摄全景X线片和头颅定位侧位片。通过全景X线片观察下颌M3阻生或萌出的情况,将其分为阻生组和萌出组,并对其X线头颅侧位片进行头影测量分析。结果阻生组与萌出组的下颌体长度(Go-Po’)、下颌支宽度(W)、下颌平面角(MP-FH)、前下面高(ANS-Me)、下颌支长度与下颌骨长度的比值(Co-Go/Co-Po)的差异有统计学意义(P<0.05),阻生组的W、Co-Go/Co-Po大于萌出组,而Go-Po’、ANS-Me、MP-FH小于萌出组。两组间的Co-Po、Co-Go、上下中切牙角、上牙槽座点-鼻根点-下牙槽座点角的差异无统计学意义(P>0.05)。结论下颌M3的近中向阻生和萌出可能与下颌的旋转生长及面部生长型有关,下颌向前旋转和短面型患者的下颌M3更易发生近中向阻生。     

正常人腭咽闭合不全参数—X线头影测量研究

目的　建立正常人生理性腭咽闭合不全参数,为评价腭裂患者腭咽闭合功能和软腭活动提供一种客观的方法。方法　采用 Ｘ 线头影定位测量分析技术对 ２２２ 名腭咽闭合不全（ｖｅｌｏｐｈａｒｙｎｇｅａｌｉｎｃｏｍ ｐｅｔｅｎｃｅ, Ｖ Ｐ Ｉ）的正常人群进行分析研究,建立了正常人 Ｘ线头颅定位测量腭咽闭合功能参数。结果　 Ｘ 线的腭咽闭合矢状收缩不全率（ Ｒ Ｖ Ｓ Ｒ）与鼻咽内窥镜检查的腭咽闭合不全率（ Ｒ Ｖ Ｐ Ｉ）呈显著的相关关系。结论　 Ｘ 线头影测量方法是评价腭咽闭合功能和软腭活动的一种有效方法。     

青少年下颌后缩患者颅颌面硬组织结构特征的Delaire头影测量初步分析

目的采用Delaire头影测量法分析重庆地区青少年下颌后缩患者颅颌面硬组织特征及其补偿机制,为进一步诊断、治疗设计及预后分析提供参考。方法选取重庆地区11～14岁下颌后缩患者56例及正常青少年40例为研究对象,拍摄头颅侧位片,采用传统头影测量法和Delaire头影测量法分析其颅颌面硬组织结构特征。结果传统头影测量法分析发现,与正常相比,下颌后缩患者∠SNB、Co-Go、Co-Pog、U1-L1减小,∠ANB、∠SN-MP、L1-MP增大,∠SNA、Go-Pog无统计学差异。Delaire头影测量法分析发现,下颌后缩患者∠1、∠5、（Cp-Oi）/C2减小,∠2、（M-Cp）/C2、∠3、∠4增大,C3/C2、NP-F1无统计学差异;Me-F1为-8.70 mm±2.48 mm,Me-Met为5.74 mm±2.58 mm。结论Delaire头影测量法可较直观地定量评估下颌后缩患者颅颌面骨骼结构特征及其补偿机制,下颌后缩畸形主要由下颌骨相对后移及下颌骨发育不足所致。     

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目的评价4种垂直向头影测量指标对AngleI类错畸形颌骨垂直向关系的可靠性。方法选择中国医科大学口腔医学院正畸科2004—2007年收治的52例AngleI类错成人患者的头颅侧位片,通过头影测量分析其前颅底平面SN与下颌平面MP所呈前下角(SN-GoGn角)、后面高S-Go与前面高N-Gn的比值(Facial Height Ratio)、鞍角N-S-Ar与关节角S-Ar-Go及下颌角Ar-Go-Me三个角之和(The three angle)、垂直向异常指数(ODI,即AB平面与下颌平面夹角±腭平面与眶耳平面夹角,当腭平面斜向下前方时为"+",当腭平面斜向上前方时为"-")4种指标,计算4种指标的变异系数,并进行相关分析。结果SN-GoGn、Facial Height Ratio、The three angle与ODI的变异系数分别为0.173、0.092、0.016和0.085,且4种指标间均有相关关系。结论SN-GoGn、Facial Height Ratio、The three angle与ODI均可作为评价AngleI类错颌骨垂直向关系的指标,但The three angle更具有可靠性。     

头影测量标志点计算机自动识别的初步研究

目的初步探讨计算机头影测量自动定点技术。方法随机选择20张头颅侧位片作为待测图像,另选1张高质量的X线片为标准图像。使用仿射变换结合模板匹配的方法来识别标志点。首先在标准图像上手工确定各标志点的位置并建立标志点的标准模板;然后用仿射变换的方法把标志点从标准图像变换到待测图像上,获得标志点的初始位置;最后经模板匹配确定标志点的准确位置。结果共识别出11个硬组织点和10个软组织点。硬组织点平均误差2.28 mm,软组织点平均误差0.77 mm。有4个硬组织标志点的定点误差<2 mm。结论初步建立了头影测量标志点自动识别系统,但整体上标志点识别的准确性尚不能满足临床应用要求。     

三维头影测量的研究现状与展望

随着锥体束CT(cone beam computed tomography,CBCT)在正畸领域的广泛使用,越来越多正畸医生开始研究使用CBCT影像进行三维头影测量分析.三维头影测量分析是需要基于CT或者CBCT获得患者的三维头颅影像,并使用具有三维分析功能的软件进行测量与分析.本文就三维头影测量的定义与发展、头颅定位、定点、测量项目及参考值的确定和影像重叠五个方面进行综述,并对其今后发展方向进行展望.