CT仿真内镜开口阈值在诊断骨性蜗神经管发育不良中的初步应用

Detection of hypoplasia of bony cochlear nerve canal by the opening threshold of virtual endoscopy:a pilot study

目的:探讨CT仿真内镜开口阈值诊断骨性蜗神经管发育不良的价值.方法:两个放射科医师分别测量20个骨性蜗神经管发育不良耳及100个正常耳仿真内镜开口阈值;同时在CT横轴位图像上测量骨性蜗神经管宽度.用Spearman相关系数分析骨性蜗神经管的宽度与仿真内镜开口阈值的相关性,用ROC曲线计算CT仿真内镜开口阈值诊断骨性蜗神经管发育不良最佳的敏感度和特异度.结果:病例组骨性蜗神经管开口阈值((926±308)HU)明显高于对照组开口阈值((287±72)HU),病例组与对照组骨性蜗神经管平均宽度分别约为(0.83±0.36)mm、(2.21±0.35)mm.骨性蜗神经管仿真内镜开口阈值与宽度之间具有较好的负线性相关(Spearman相关系数-0.768,P<0.001),ROC曲线显示如果仿真内镜开口阈值设定为408 HU,可提供较合理的敏感度(85%)和特异度(94%).结论:CT仿真内镜开口阈值可以作为一种较好的诊断骨性蜗神经管发育不良的方法.

Objective:To examine diagnostic accuracy of computed tomography virtual endoscopy(CTVE)in the evaluation of bony cochlear nerve canal(BCNC)hypoplasia on basis of opening threshold.Methods:Twenty ears diagnosed with BCNC hypoplasia were included in this study.One hundred ears served as controls.The opening thresholds were measured by two reviewers.The width of BCNC was obtained on transverse CT images.Association between the width of BCNC and opening threshold was assessed by using Spearman correlation coefficient.ROC curves were applied to assess the best cut-off value of opening thresholds.Results:The opening threshold of BCNC was significantly higher in diseased ears((926±308)HU)than that in control ears((287±72)HU).Inter-observer agreement was very good.The mean widths of BCNC for diseased ears and control ears were(0.83±0.36)mm and(2.21±0.35)mm,respectively.Significant negative linear correlation was found between opening thresholds and width of BCNC(Spearman coefficient-0.768,P<0.001).The cut-off opening thresholds of 408 HU for differentiation between the two groups provided the best combination of sensitivity(85%)and specificity(94%).Conclusion:The CTVE with opening threshold may be an effective optional tool for prediction of hypoplasia of BCNC.