Koob Andreas, Sanden Etje, Hassfeld Stefan, Staehle Hans Jörg, Eickholz Peter
Poliklinik für Parodontologie, University of Frankfurt, Theodor-Stem-Kai 7, 60590 Frankfurt, Germany.
Am J Dent. 2004 Dec;17(6):388-93.
To compare different image processing modes (filters) on the reproducibility and accuracy of the assessment of proximal carious lesions viewed in direct digital radiographs. Variables studied were exposure time and tissue scatter radiation.
Standardized direct digital radiographs of 50 extracted teeth were obtained and 44 areas of proximal caries were detected histologically. Four radiographs were obtained of each tooth using a charge coupled device sensor. Two radiographs were obtained with and two without tissue scatter radiation equivalent (TSRE) each of them at normal exposure time (0.06 second) and underexposed (0.01 second). On each of the 200 radiographs, the central depth (CD) of each carious lesion was measured at 21-fold magnification both on the unchanged image and after use of two different filters (median, median plus inversion). All measurements were repeated after 1 week to estimate reproducibility. Histometric CD assessments provided a gold standard for comparison with the radiographic measurements (accuracy).
Whereas reproducibility was not influenced significantly by any of the investigated parameters, defect type and exposure time influenced the overall accuracy of CD measurements. Basic digital filtering of radiographic images failed to result in statistically significant improvement of the accuracy of CD measurements.
比较不同图像处理模式（滤波器）对直接数字化X线片中近中龋损评估的可重复性和准确性。研究的变量为曝光时间和组织散射辐射。
获取50颗离体牙的标准化直接数字化X线片，并通过组织学方法检测出44个近中龋损区域。使用电荷耦合器件传感器为每颗牙齿获取四张X线片。其中两张在正常曝光时间（0.06秒）且有组织散射辐射等效物（TSRE）的情况下获取，另外两张在正常曝光时间且无TSRE的情况下获取，还有两张在低曝光（0.01秒）且有TSRE的情况下获取，最后两张在低曝光且无TSRE的情况下获取。在200张X线片中的每一张上，分别在未处理的图像以及使用两种不同滤波器（中值、中值加反转）处理后的图像上，以21倍放大率测量每个龋损的中心深度（CD）。所有测量在1周后重复进行以评估可重复性。组织计量学CD评估为与X线测量结果进行比较（准确性）提供了金标准。
尽管可重复性未受到任何研究参数的显著影响，但缺损类型和曝光时间影响了CD测量的总体准确性。对X线图像进行基本数字滤波未能在统计学上显著提高CD测量的准确性。
