单神经管超高分辨力CT影像解剖学的实验研究

Experimental study on ultra-high resolution CT imaging anatomy of single neural canal

目的:应用超高分辨力CT(U-HRCT)观察单神经管的形态特点并进行测量,对单神经管的解剖形态再认识。方法:2019年12月至2020年1月间使用U-HRCT对52例(104耳)人体头颅标本进行扫描,重组显示单神经管最佳的标准横断面和冠状面图像。观察单神经管主干和分支形态,根据转折点数量将单神经管主干分为单折点、双折点、无折点型,根据分支形态将有分支的单神经管分为分叉型、汇合型、侧支型、双侧分支型。测量单神经管主干壶腹端、折点及内耳道端的管径、夹角和各段长度。采用独立样本t检验或Mann-Whitney U检验比较有无分支单神经管主干管径的差异。结果:52例(104耳)单神经管主干分为单折点型79耳、双折点型20耳及无折点型5耳。双侧形态分型相同30例(60耳),其中单折点型24例(48耳)、双折点型5例(10耳)、无折点型1例(2耳),22例(44耳)左右形态不同。单折点型单神经管壶腹端、转折点和内耳道端管径为(0.31±0.07)、(0.40±0.10)、(0.46±0.10)mm,夹角为60.5°±7.8°、120.3°±9.6°、38.3°±7.5°,壶腹侧、内耳道侧长度为(1.95±0.38)、(2.31±0.68)mm。双折点型壶腹端、近壶腹侧转折点、近内耳道侧转折点、内耳道端管径为(0.32±0.09)、(0.38±0.09)、(0.47±0.12)、(0.47±0.13)mm,角度为60.9°(57.3°,64.9°)、117.9°±12.3°、129.6°±12.4°、41.7°(32.9°,79.5°),壶腹侧、两转折点间、内耳道侧长度为(1.78±0.31)、0.96(0.80,1.15)、0.65(0.46,1.15)mm。无折点型壶腹端和内耳道端管径分别为(0.20±0.01)、(0.50±0.12)mm,与壶腹和内耳道夹角角度分别为58.4°±9.6°、46.2°±5.1°,长度为(3.61±0.32)mm。48耳存在分支,其中分叉型36耳、汇合型4耳、侧支型5耳、双侧分支型3耳。在单折点型单神经管中,无分支者转折点处管径较有分支宽(t=2.11,P=0.039);双折点型单神经管中,有无分支间各管径差异无统计学意义(P均>0.05)。结论:U-HRCT能够清晰显示单神经管,单神经管主干及分支影像所见形态多样,需重新认识其解剖形态。

Objective To re-identify the anatomical features of singular nerve canal(SNC)through observing and measuring the morphological characteristics of SNC using ultra-high resolution CT(U-HRCT).Methods The U-HRCT images of 52 human head specimens(104 ears)from December 2019 to January 2020 were obtained.The best standard cross-sectional and coronal images of SNC were reconstructed.The morphology of the main trunk and branches of the SNC were observed.According to the number of turning points,the trunks of SNC were divided into single turning point type,double turning point type and no turning point type.According to the branch morphology,the branched SNC were divided into bifurcated type,confluent type,side branch type and bilateral branch type.The diameter,angle and length of each section of the posterior canal ampulla(PCA)of the main trunk,the turning point and the internal auditory meatus(IAM)were measured.Independent sample t test or Mann-Whitney U test was used to test group differences of main trunk diameter of the SNC with or without branches.Results Totally 104 ears of 52 cases were divided into single turning point type of 79 ears,double turning point type of 20 ears and no turning point type of 5 ears.The bilateral morphological classification was the same in 30 cases(60 ears),including 24 cases of single turning point type(48 ears),5 cases of double turning point type(10 ears),and 1 case of no turning point type(2 ears).The ear morphology on both sides was different in 22 cases(44 ears).The diameters of the PCA,the turning point and the IAM of SNC with single turning point type were(0.31±0.07),(0.40±0.10),(0.46±0.10)mm,respectively,and the angles were 60.5°±7.8°,120.3°±9.6°,38.3°±7.5°respectively.And the length of the PCA and the IAM in the SNC with single turning point type were(1.95±0.38),(2.31±0.68)mm,respectively.The diameters of the PCA,the turning point near the PCA,the turning point near the IAM and the IAM of SNC with double turning point type were(0.32±0.09),(0.38±0.09),(0.47±0.12),(0.47±0.13)mm,and the angle were 60.9°(57.3°,64.9°),117.9°±12.3°,129.6°±12.4°,41.7°(32.9°,79.5°),respectively.The length of the PCA,the IAM and the distance between these two turning points were(1.78±0.31),0.65(0.46,1.15),0.96(0.80,1.15)mm,respectively.The diameters of the PCA and the IAM of SNC without turning point type were(0.20±0.01)and(0.50±0.12)mm.The angles with the PCA and the IAM in these cases were 58.4°±9.6°and 46.2°±5.1°,and the length was(3.61±0.32)mm.A total of 48 ears had branches,including bifurcated type(36 ears),confluence type(4 ears),side branch type(5 ears)and bilateral branch type(3 ears).In the SNC group with single turning point,the diameter of the turning point in the cases without branches was wider than that of cases with branches(t=2.11,P=0.039).However,there was no significant difference in the diameter of each section between these two subgroups of SNC cases with double turning point type.Conclusions U-HRCT is able to clearly show the SNC,the imaging features of whom are variable and should be re-understood.