10μm超高分辨率CT显示眼眶内壁筛孔的可行性研究

Feasibility study of ethmoidal foramen in the medial wall of the orbit based on 10μm ultra-high resolution CT

目的探讨10μm超高分辨CT(ultra-high resolution CT,U-HRCT)显示和评估眼眶内壁筛孔的可行性。方法收集10%福尔马林溶液固定的成人头颅标本9个(眼眶18侧),应用U-HRCT和常规多层螺旋CT(multislice helical CT,MSCT)采集眼眶CT图像。两位放射科医师对图像质量进行客观和主观评价,记录筛孔显示情况,并测量筛孔间距离。结果两位医师客观和主观评价结果无显著性差异且一致性较好。U-HRCT和MSCT的信噪比(signal-noise ratio,SNR)分别是43.09±8.87和11.04±0.66,对比噪声比(contrast noise ratio,CNR)分别是2.13±1.45和0.55±0.13。U-HRCT的CNR和SNR均明显高于MSCT(P<0.05)。U-HRCT和MSCT的主观评分分别是10.00分(9.00分,10.00分)和6.00分(5.75分,7.00分),U-HRCT主观评分明显高于MSCT(P<0.05)。18侧筛前孔U-HRCT和MSCT均能显示。U-HRCT和MSCT分别显示筛后孔18侧和17侧,两者无显著性差异(P>0.05)。U-HRCT和MSCT分别显示副筛孔9侧(单孔7侧,双孔2侧)和2侧(单孔2侧),两者具有显著性差异(P<0.05)。副筛孔至筛前孔、筛后孔以及筛前孔至筛后孔距离分别是(9.43±1.13)mm、(4.75±1.09)mm、(14.18±1.14)mm。结论U-HRCT对眼眶内壁筛孔评估明显优于MSCT,能够准确显示筛孔部位、数量并进行距离测量,为临床术前提供更加精准的个体化信息。

OBJECTIVE To investigate the feasibility of ultra-high resolution CT(U-HRCT)in demonstrating and evaluating ethmoidal foramen in the medial wall of the orbit.METHODS Nine cadavers(18 side orbits)fixed in 10%buffered formalin were enrolled and underwent U-HRCT and multislice helical CT(MSCT).Subjective and objective evaluations of image quality were performed by two experienced radiologists independently.Anterior,middle,and posterior ethmoidal foramen(AEF,MEF,and PEF)were recorded and the distance among them was measured.RESULTS The results of subjective and objective evaluations were not significant differences between evaluators and consistency was strong.CNR of U-HRCT and MSCT were 43.09±8.87 and 11.04±0.66 and SNR were 2.13±1.45 and 0.55±0.13,respectively.CNR and SNR of U-HRCT were significantly higher than MSCT(P<0.05).Objective scores of the U-HRCT and MSCT groups were 10.00 points(9.00 points,10.00 points)and 6.00 points(5.75 points,7.00 points).Objective scores of the U-HRCT were higher than MSCT(P<0.05).All eighteen AEF were shown by U-HRCT and MSCT.Among 18 PEF showed by U-HRCT,17 of them demonstrated by MSCT,and no significant difference was found in the display rate between groups(P>0.05).Nine MEF(7 single hole and 2 double holes)were found by U-HRCT,but only 2 of them were shown by MSCT.The MEF display rate of U-HRCT was higher than MSCT(P<0.05).The distance from MEF to AEF,from MEF to PEF,and from AEF to PEF were(9.43±1.13)mm,(4.75±1.09)mm,(14.18±1.14)mm,respectively.CONCLUSION U-HRCT is better to evaluate ethmoidal foramen than MSCT.It could be used to show the number and position of ethmoidal foramen before surgery to avoid complications.