三维CT成像诊断髁突骨折的临床研究
作者：吴汉江 罗建光 朱兆夫
单位：吴汉江(湖南医科大学附属第二医院口腔科 410011)；朱兆夫(湖南医科大学附属第二医院口腔科 410011)；罗建光(湖南医科大学附属第二医院放射科)
关键词：计算机体层摄影；髁突骨折；三维重建
华西口腔医学杂志000112 摘 要：目的:探讨获得高质量颞颌关节三维CT影像的方法,评价其对髁突骨折的诊断价值。方法:对14例髁突骨折患者,采用3种扫描方式(横断、冠状、螺旋),2种扫描范围(横断位:眶耳平面上方1 cm至下颌升支中份或颏下点。冠状位:乳突至下颌升支前缘或颏前点。)和2种层厚(2.5 mm、5.0 mm)扫描,以勾画法删除层面影像中的颈椎、茎突、枕骨和部分乳突,表面阴影显示法(SSD)完成三维重建。结果:2.5 mm薄层横断扫描获得的三维重建影像质量最佳,勾画删除技术的应用有利于消除颈椎等对骨折观察的影响。14例患者检出髁突骨折21侧,骨折部位、髁突移位情况显示理想。结论:薄层横断扫描配合勾画删除技术,可获得高质量三维重建影像,准确、直观地显示髁突骨折情况。
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Clinical Study of Three-dimensional Reconstruction of Computed Tomography in Diagnosis of Condylar Fractures
Wu Hanjiang Luo Jianguang Zhu Zhaofu
(The Second Affiliated Hospital, Hunan Medical University)
Abstract：Objective：To explore a method of getting good three-dimensional (3D) reconstraction images of temporomandibular joint (TMJ) by computed tomography (CT), and evaluate diagnosis value of 3DCT in condylar fractures. Methods: Of the 14 patients studied, 12 were male and 2 were female with age ranging from 4 to 37 years old. 4 were old fractures and the other 10 were fresh fractures. All patients′ orthopanotomograms were taken first, and then were scanned with CT. The scanning conditions were 300～345 mAS and 120kV, and the canning methods included cross-sectional (11/14), coronal-sectional (2/14) and spiral (1/14) (pitch:1, thickness of layers:2.5 mm) scanning. Scanning scopes: The cross-sectional and spiral scanning were from 1 cm above the Frankfort horizontal plane to the middle of the mandibular ramus or Menton; The coronal-sectional scanning was from the mastoid process to the anterior point of the mandibular ramus or Pogonion. The thickness of the scanning layers was 2.5 mm (12/14) or 5 mm (2/14). Finally, 3D reconstructed images were obtained by shaded surface display (SSD). The cross-sectional images were obtained by being removed the cervical vertibra, the styloid process, the occipital bone and part of the mastoid process with Subtract Manual Irroi before reconstruction to avoid interference with the observation of TMJ and skull basis. Results: ①The best 3D CT reconstructed images were obtained by 2.5mm-thin-layer cross-sectional scanning by being removed parts of the adjacent structures, and the bone lines were clear and smooth without adjacent bone structures shading TMJ. The quality of images taken spirally was similar to those taken cross-sectionally. While the coronal scanning neglected some important anatomic symbols which might be valuable to diagnose condylar displacement. ②Of the 14 patients, 7 were unilateral condylar fractures and 7 were bilateral (21 sides altogether), among which 18 sides were high fractures of condyles and 3 were fractures of condylar neck. High oblique line fractures and comminuted fractures had major condylar rotation displacement which moved forward, downward and inside, whereas, vertical fractures only had minor displacement. Inward rotation displacement occured in medial bent fractures. 10 of 14 patients (15 sides) had been conducted operation, and the same situations as seen from 3DCT reconstructed images were found.Conclusion: 3DCT images can display condylar fractures accurately and directly, and are very useful for surgeons to select treating methods of condylar fractures.
, 百拇医药
Key words：computed tomography condylar fractures three-dimensional reconstruction▲
从1983年Vannier[1]首次将三维CT成像技术应用于颅面外科以来,目前已成为骨科、整形外科和颌面外科等学科的一项有价值的检查手段[2]。1984年Roberts[3]首次介绍了采用CT三维重建技术获得颞颌关节三维立体影像的方法。1988年Mayer[4]报告了其在颌面部骨折诊断中的应用。但是,国内尚未见三维CT成像诊断髁突骨折临床研究的报告。笔者从1996～1998年对14例(21侧)髁突骨折患者采用多种扫描方式进行三维重建,探讨获得高质量影像的方法。
1 材料和方法
1.1 研究对象
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选择1996～1998年在湖南医科大学附属第二医院口腔科就诊的14例髁突骨折患者为研究对象,其中男12例,女2例,年龄4～37岁。14例中新鲜骨折10例,陈旧性骨折4例。6例为单纯髁突颈部骨折,7例伴下颌骨骨折,1例伴上下颌骨骨折。5例患者CT扫描前已行颌间牵引复位,咬合关系恢复良好。
1.2 设备及方法
采用以色列Elscint CT Twin双螺旋CT机,德国西门子曲面体层X线机。全部病例均先拍曲面体层片,再行CT非增强扫描。扫描条件:300～345 mAs,120 kV。扫描方式:横断扫描(11例)、冠状扫描(2例),螺旋扫描1例(螺距为1,层厚2.5 mm)。扫描范围:①横断扫描:眶耳平面上方1 cm至下颌升支中份或颏下点。②冠状扫描:乳突至下颌升支前缘或颏前点。扫描层面厚度:2.5 mm(12例)和5.0 mm(2例)。三维重建方法:表面阴影显示法(SSD)。在横断扫描的病例重建前先用勾画法去除颈椎、茎突、枕骨及部分乳突,以避免这些结构影响对颞颌关节和颅底的观察。在显示屏旋转三维重建影像,选择理想位置的拍片。
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2 结 果
采用2.5 mm薄层横断扫描,勾画法删除颈椎、茎突、枕骨和部分乳突,所获得的三维重建影像质量最佳,骨廓线清晰,颞颌关节无相邻骨结构遮挡,有利于多角度观察骨折和髁突移位情况。相同层厚的螺旋扫描获得的重建影像的质量与横断扫描相似。冠状扫描虽可在选取扫描区时删除颈椎等相邻结构,但同时也去掉了一些重要的解剖标志,不利于髁突移位的评价。扫描层厚为5.0 mm时,重建影像较粗糙,不利于骨折线和髁突移位的观察。眶耳平面上方1 cm至下颌升支中份的区段扫描不影响重建影像质量。
14例患者中,发现单、双侧髁突骨折各7例,共21侧。其中髁突高位骨折18侧,颈部骨折3侧。高位骨折中,关节面以下的斜行骨折11侧,经过关节面的纵行骨折3侧,粉碎性骨折4侧。3侧颈部骨折全部为内弯骨折(1侧为青枝骨折)。高位斜行骨折和粉碎性骨折髁突移位较大,大多向前下内移位,常伴有旋转(图1)。而纵行骨折移位较小(图2)。颈部内弯骨折髁突向内旋转移位(图3)。本组中10例15侧行手术复位,手术所见与三维重建影像完全一致。在已行颌间牵引复位的病例,未观察到移位的髁突有复位迹象。
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图1 左髁突关节面以下斜行骨折(后前位)
A 髁突前下内方移位, B 下颌升支上移骨折断面与关节窝接触
图2 左髁突纵行骨折(斜侧位)
A 移位的髁突, B 残余髁突, C 关节窝
图3 双侧髁突陈旧性骨折(后前位)
A 左侧移位的髁突,已错位愈合; B 残余髁突与关节窝融合; C 右侧髁突内弯移位
3 讨 论
3.1 获得最佳三维CT影像的扫描方法
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本结果显示:当扫描层厚为2.5 mm时,无论采用横断、冠状或螺旋方式,均可获得清晰的颞颌关节三维重建影像。横断扫描获得的重建影像,可同时显示颞颌关节窝、髁突及其邻近的骨性解剖标志,有利于评价髁突移位的空间位置关系。由于颈椎、茎突、枕骨、乳突等结构的存在,干扰了对骨折的观察,笔者在进行三维重建前,采用勾画法删去各层面的上述结构,有利于从多角度观察髁突的骨折和髁突移位情况。选择眶耳平面上方1 cm至下颌升支中份的区段扫描,可减少扫描层次,同时能获得高质量的三维重建影像,不影响对骨折的观察。已行颌间结扎的病例,区段扫描可避免金属牙弓夹板所产生的伪影对重建影像质量的影响。
3.2 三维CT成像在髁突骨折的诊断价值
髁突骨折的部位、移位的方向和程度,以及下颌升支与颞下颌关节窝的关系,在髁突骨折的治疗抉择中有十分重要的意义[5]。而临床常用的下颌骨曲面体层和下颌骨开口后前位片却难以提供准确的信息。虽然CT扫描的应用提高了诊断水平,但这种层面影像仍不能提供一个直观的立体影像,临床医生必需借助解剖知识,结合多层面影像来判断移位的髁突与关节窝的空间位置关系[6]。本组资料也表明:CT横断和冠状扫描影像在诊断上有其局限性。横断扫描能提示髁突的移位方向及其旋转和移位程度,但不能显示骨折线的部位和髁突与关节窝的关系。冠状扫描虽可显示骨折线的部位,髁突向内外移位情况和与关节窝的关系,但对髁突前后向移位和旋转移位显示不佳,二者均不能直观地显示骨折后髁突与关节窝的空间位置。而这种独特的三维立体影像,能准确、真实地再现髁突骨折的情况,对髁突骨折的诊断有着十分重要的价值。但由于颈椎、茎突、枕骨、乳突等结构的存在,影响对移位髁突的观察[7]。笔者采用薄层横断扫描加勾画法获得清晰的三维重建影像,可以在显示屏上从多角度准确了解髁突骨折的部位、髁突移位的方向和程度,以及与关节窝的关系。为治疗抉择提供了可靠的依据。
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3.3 颌间牵引对移位髁突的影响
本组料中有5例8侧髁突骨折在CT检查前已行颌间牵引复位治疗,咬合关系恢复良好。但在三维重建影像中未观察到移位的髁突有复位迹象,髁突仍处于移位或脱位状态。这与Choi[5]的报告相似。因此,笔者认为:颌间牵引复位法只能使咬合关系暂时恢复,不能使移位的髁突复位,保守治疗的结果是骨折错位愈合、改建。这可能是髁突骨折保守治疗后出现错,下颌运动障碍、咀嚼功能不良和疼痛等症状的原因。■
参考文献：
[1]Vannier MW, Mash JL, Warren JD. Three-dimensional CT reconstruction images of craniofacial surgical planning and evaluation. Radiology, 1984,150(1):179～184
, http://www.100md.com
[2]沈国芳综述.三维CT影像学及其在头颈外科的应用.国外医学口腔医学分册,1990,17(2):65～68
[3]Roberts D, Pettigrew J, Udupa J, et al. Three-dimensional imaging and display of the temporomandibular joint. Oral Surg Oral Med Oral Pathol, 1984,58(4):461～474
[4]Mayer JS, Wainwright DT, Yeakley JW, et al. The role of three-dimensional computed tomography in the management of maxillofacial trauma. J Trauma, 1988,28(7):1043～1053
[5]华春清综述.髁状突骨折术治疗的现代评价.国外医学口腔医学分册,1998,25(1):19～22
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[6]Marden E, Alder DM, Thomas D, et al. Clinical usefulness of two-dimensional reformed and three-dimensionally rendered computerized tomographic images. J Oral Maxillofac Surg, 1995,53(4):375～386
[7]Luka B, Brechtelsbauer D, Gellrich NC, et al. 2D and 3D CT reconstructions of the facial skeletion: an unnecessary option or a diagnostic pearl. Int J Oral Maxillofac Surg, 1995,24(1):76～83
收稿日期：1998-05-20
修稿日期：1999-06-15, http://www.100md.com
单位：吴汉江(湖南医科大学附属第二医院口腔科 410011)；朱兆夫(湖南医科大学附属第二医院口腔科 410011)；罗建光(湖南医科大学附属第二医院放射科)
关键词：计算机体层摄影；髁突骨折；三维重建
华西口腔医学杂志000112 摘 要：目的:探讨获得高质量颞颌关节三维CT影像的方法,评价其对髁突骨折的诊断价值。方法:对14例髁突骨折患者,采用3种扫描方式(横断、冠状、螺旋),2种扫描范围(横断位:眶耳平面上方1 cm至下颌升支中份或颏下点。冠状位:乳突至下颌升支前缘或颏前点。)和2种层厚(2.5 mm、5.0 mm)扫描,以勾画法删除层面影像中的颈椎、茎突、枕骨和部分乳突,表面阴影显示法(SSD)完成三维重建。结果:2.5 mm薄层横断扫描获得的三维重建影像质量最佳,勾画删除技术的应用有利于消除颈椎等对骨折观察的影响。14例患者检出髁突骨折21侧,骨折部位、髁突移位情况显示理想。结论:薄层横断扫描配合勾画删除技术,可获得高质量三维重建影像,准确、直观地显示髁突骨折情况。
, 百拇医药
Clinical Study of Three-dimensional Reconstruction of Computed Tomography in Diagnosis of Condylar Fractures
Wu Hanjiang Luo Jianguang Zhu Zhaofu
(The Second Affiliated Hospital, Hunan Medical University)
Abstract：Objective：To explore a method of getting good three-dimensional (3D) reconstraction images of temporomandibular joint (TMJ) by computed tomography (CT), and evaluate diagnosis value of 3DCT in condylar fractures. Methods: Of the 14 patients studied, 12 were male and 2 were female with age ranging from 4 to 37 years old. 4 were old fractures and the other 10 were fresh fractures. All patients′ orthopanotomograms were taken first, and then were scanned with CT. The scanning conditions were 300～345 mAS and 120kV, and the canning methods included cross-sectional (11/14), coronal-sectional (2/14) and spiral (1/14) (pitch:1, thickness of layers:2.5 mm) scanning. Scanning scopes: The cross-sectional and spiral scanning were from 1 cm above the Frankfort horizontal plane to the middle of the mandibular ramus or Menton; The coronal-sectional scanning was from the mastoid process to the anterior point of the mandibular ramus or Pogonion. The thickness of the scanning layers was 2.5 mm (12/14) or 5 mm (2/14). Finally, 3D reconstructed images were obtained by shaded surface display (SSD). The cross-sectional images were obtained by being removed the cervical vertibra, the styloid process, the occipital bone and part of the mastoid process with Subtract Manual Irroi before reconstruction to avoid interference with the observation of TMJ and skull basis. Results: ①The best 3D CT reconstructed images were obtained by 2.5mm-thin-layer cross-sectional scanning by being removed parts of the adjacent structures, and the bone lines were clear and smooth without adjacent bone structures shading TMJ. The quality of images taken spirally was similar to those taken cross-sectionally. While the coronal scanning neglected some important anatomic symbols which might be valuable to diagnose condylar displacement. ②Of the 14 patients, 7 were unilateral condylar fractures and 7 were bilateral (21 sides altogether), among which 18 sides were high fractures of condyles and 3 were fractures of condylar neck. High oblique line fractures and comminuted fractures had major condylar rotation displacement which moved forward, downward and inside, whereas, vertical fractures only had minor displacement. Inward rotation displacement occured in medial bent fractures. 10 of 14 patients (15 sides) had been conducted operation, and the same situations as seen from 3DCT reconstructed images were found.Conclusion: 3DCT images can display condylar fractures accurately and directly, and are very useful for surgeons to select treating methods of condylar fractures.
, 百拇医药
Key words：computed tomography condylar fractures three-dimensional reconstruction▲
从1983年Vannier[1]首次将三维CT成像技术应用于颅面外科以来,目前已成为骨科、整形外科和颌面外科等学科的一项有价值的检查手段[2]。1984年Roberts[3]首次介绍了采用CT三维重建技术获得颞颌关节三维立体影像的方法。1988年Mayer[4]报告了其在颌面部骨折诊断中的应用。但是,国内尚未见三维CT成像诊断髁突骨折临床研究的报告。笔者从1996～1998年对14例(21侧)髁突骨折患者采用多种扫描方式进行三维重建,探讨获得高质量影像的方法。
1 材料和方法
1.1 研究对象
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选择1996～1998年在湖南医科大学附属第二医院口腔科就诊的14例髁突骨折患者为研究对象,其中男12例,女2例,年龄4～37岁。14例中新鲜骨折10例,陈旧性骨折4例。6例为单纯髁突颈部骨折,7例伴下颌骨骨折,1例伴上下颌骨骨折。5例患者CT扫描前已行颌间牵引复位,咬合关系恢复良好。
1.2 设备及方法
采用以色列Elscint CT Twin双螺旋CT机,德国西门子曲面体层X线机。全部病例均先拍曲面体层片,再行CT非增强扫描。扫描条件:300～345 mAs,120 kV。扫描方式:横断扫描(11例)、冠状扫描(2例),螺旋扫描1例(螺距为1,层厚2.5 mm)。扫描范围:①横断扫描:眶耳平面上方1 cm至下颌升支中份或颏下点。②冠状扫描:乳突至下颌升支前缘或颏前点。扫描层面厚度:2.5 mm(12例)和5.0 mm(2例)。三维重建方法:表面阴影显示法(SSD)。在横断扫描的病例重建前先用勾画法去除颈椎、茎突、枕骨及部分乳突,以避免这些结构影响对颞颌关节和颅底的观察。在显示屏旋转三维重建影像,选择理想位置的拍片。
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2 结 果
采用2.5 mm薄层横断扫描,勾画法删除颈椎、茎突、枕骨和部分乳突,所获得的三维重建影像质量最佳,骨廓线清晰,颞颌关节无相邻骨结构遮挡,有利于多角度观察骨折和髁突移位情况。相同层厚的螺旋扫描获得的重建影像的质量与横断扫描相似。冠状扫描虽可在选取扫描区时删除颈椎等相邻结构,但同时也去掉了一些重要的解剖标志,不利于髁突移位的评价。扫描层厚为5.0 mm时,重建影像较粗糙,不利于骨折线和髁突移位的观察。眶耳平面上方1 cm至下颌升支中份的区段扫描不影响重建影像质量。
14例患者中,发现单、双侧髁突骨折各7例,共21侧。其中髁突高位骨折18侧,颈部骨折3侧。高位骨折中,关节面以下的斜行骨折11侧,经过关节面的纵行骨折3侧,粉碎性骨折4侧。3侧颈部骨折全部为内弯骨折(1侧为青枝骨折)。高位斜行骨折和粉碎性骨折髁突移位较大,大多向前下内移位,常伴有旋转(图1)。而纵行骨折移位较小(图2)。颈部内弯骨折髁突向内旋转移位(图3)。本组中10例15侧行手术复位,手术所见与三维重建影像完全一致。在已行颌间牵引复位的病例,未观察到移位的髁突有复位迹象。
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图1 左髁突关节面以下斜行骨折(后前位)
A 髁突前下内方移位, B 下颌升支上移骨折断面与关节窝接触
图2 左髁突纵行骨折(斜侧位)
A 移位的髁突, B 残余髁突, C 关节窝
图3 双侧髁突陈旧性骨折(后前位)
A 左侧移位的髁突,已错位愈合; B 残余髁突与关节窝融合; C 右侧髁突内弯移位
3 讨 论
3.1 获得最佳三维CT影像的扫描方法
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本结果显示:当扫描层厚为2.5 mm时,无论采用横断、冠状或螺旋方式,均可获得清晰的颞颌关节三维重建影像。横断扫描获得的重建影像,可同时显示颞颌关节窝、髁突及其邻近的骨性解剖标志,有利于评价髁突移位的空间位置关系。由于颈椎、茎突、枕骨、乳突等结构的存在,干扰了对骨折的观察,笔者在进行三维重建前,采用勾画法删去各层面的上述结构,有利于从多角度观察髁突的骨折和髁突移位情况。选择眶耳平面上方1 cm至下颌升支中份的区段扫描,可减少扫描层次,同时能获得高质量的三维重建影像,不影响对骨折的观察。已行颌间结扎的病例,区段扫描可避免金属牙弓夹板所产生的伪影对重建影像质量的影响。
3.2 三维CT成像在髁突骨折的诊断价值
髁突骨折的部位、移位的方向和程度,以及下颌升支与颞下颌关节窝的关系,在髁突骨折的治疗抉择中有十分重要的意义[5]。而临床常用的下颌骨曲面体层和下颌骨开口后前位片却难以提供准确的信息。虽然CT扫描的应用提高了诊断水平,但这种层面影像仍不能提供一个直观的立体影像,临床医生必需借助解剖知识,结合多层面影像来判断移位的髁突与关节窝的空间位置关系[6]。本组资料也表明:CT横断和冠状扫描影像在诊断上有其局限性。横断扫描能提示髁突的移位方向及其旋转和移位程度,但不能显示骨折线的部位和髁突与关节窝的关系。冠状扫描虽可显示骨折线的部位,髁突向内外移位情况和与关节窝的关系,但对髁突前后向移位和旋转移位显示不佳,二者均不能直观地显示骨折后髁突与关节窝的空间位置。而这种独特的三维立体影像,能准确、真实地再现髁突骨折的情况,对髁突骨折的诊断有着十分重要的价值。但由于颈椎、茎突、枕骨、乳突等结构的存在,影响对移位髁突的观察[7]。笔者采用薄层横断扫描加勾画法获得清晰的三维重建影像,可以在显示屏上从多角度准确了解髁突骨折的部位、髁突移位的方向和程度,以及与关节窝的关系。为治疗抉择提供了可靠的依据。
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3.3 颌间牵引对移位髁突的影响
本组料中有5例8侧髁突骨折在CT检查前已行颌间牵引复位治疗,咬合关系恢复良好。但在三维重建影像中未观察到移位的髁突有复位迹象,髁突仍处于移位或脱位状态。这与Choi[5]的报告相似。因此,笔者认为:颌间牵引复位法只能使咬合关系暂时恢复,不能使移位的髁突复位,保守治疗的结果是骨折错位愈合、改建。这可能是髁突骨折保守治疗后出现错,下颌运动障碍、咀嚼功能不良和疼痛等症状的原因。■
参考文献：
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[6]Marden E, Alder DM, Thomas D, et al. Clinical usefulness of two-dimensional reformed and three-dimensionally rendered computerized tomographic images. J Oral Maxillofac Surg, 1995,53(4):375～386
[7]Luka B, Brechtelsbauer D, Gellrich NC, et al. 2D and 3D CT reconstructions of the facial skeletion: an unnecessary option or a diagnostic pearl. Int J Oral Maxillofac Surg, 1995,24(1):76～83
收稿日期：1998-05-20
修稿日期：1999-06-15, http://www.100md.com