Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen.
Department of Clinical Medicine-Core Center for Molecular Morphology, Section for Stereology and Microscopy, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus.
Otol Neurotol. 2020 Jun;41(5):e630-e637. doi: 10.1097/MAO.0000000000002583.
To assess mastoid geometry using computed tomography (CT) scans and design-based stereological methods.
The anatomical organization of the mastoid air cell system (MACS) remains debated. Geometrical parameters have previously been determined by automated image-analysis algorithms. Stereology is an alternative approach, which has previously been applied to estimate the volume of the MACS, but has not previously been used to estimate surface area or study anisotropy.
Twenty-three clinical CT scans of aerated temporal bones obtained from various ENT patients were studied. The structural orientation and anisotropy of the MACS was investigated by test-grid rotation and rose plots. Volume, surface area, and surface area-to-volume ratio were estimated with design-based stereology.
Anisotropy of the mastoid air cells was demonstrated by a significant difference in surface area estimates between the axial and coronal planes (p = 0.0065). Rose plots illustrated variances in surface area estimates with different grid rotations, and a minimum value in the craniocaudal direction was shown. Sampling in the axial plane provided the least variance due to anisotropy. The mean (±SD) volume and surface area estimates were 5.71 ± 2.98 cm and 117 cm ± 60 cm, respectively. A large biological variation was noted. The mean (±SD) surface-to-volume ratio was 20.6 ± 2.8 cm.
The stereological technique proved to be a robust method for volume and surface area estimation in clinical CT scans. The mastoid air cells constitute an anisotropic cell-system that seems to have a predominant orientation in the craniocaudal direction.
使用计算机断层扫描（CT）评估乳突几何形状，并采用基于设计的体视学法。
乳突气房系统（MACS）的解剖结构仍存在争议。以前，几何参数是通过自动图像分析算法确定的。体视学法是一种替代方法，以前曾用于估计 MACS 的体积，但尚未用于估计表面积或研究各向异性。
研究了来自不同耳鼻喉科患者的 23 例充气颞骨的临床 CT 扫描。通过测试网格旋转和玫瑰图研究 MACS 的结构取向和各向异性。采用基于设计的体视学法估计体积、表面积和表面积与体积比。
乳突气房的各向异性通过轴向和冠状面之间表面积估计的显著差异证明（p=0.0065）。玫瑰图说明了不同网格旋转时表面积估计的差异，并显示了颅尾方向的最小值。由于各向异性，轴向平面的采样提供了最小的方差。平均（±SD）体积和表面积估计值分别为 5.71±2.98cm 和 117cm±60cm。注意到生物学变异性很大。平均（±SD）表面积与体积比为 20.6±2.8cm。
体视学法被证明是一种在临床 CT 扫描中进行体积和表面积估计的可靠方法。乳突气房构成了一种各向异性的细胞系统，在颅尾方向似乎具有主要的取向。
