Schulze R, Krummenauer F, Schalldach F, d'Hoedt B
Department of Oral Surgery, Johannes Gutenberg-University, Mainz, Germany.
Dentomaxillofac Radiol. 2000 Jan;29(1):52-6. doi: 10.1038/sj/dmfr/4600500.
To evaluate the precision and accuracy of digital measurements in digital panoramic radiography.
A series of 70 digital panoramic radiographs were obtained of a dry skull in seven different positions with metallic pins and spheres fixed to the mandible. Three replicate measurements were performed with the mouse-driven cursor by one reader at 1:1 and 2:1 magnification. Precision was assessed with the reliability index (R) and Malony/Rastogi test and the effect of magnification on accuracy by paired Wilcoxon test.
Vertical measurements were less reproducible than horizontal measurements. There were significant differences in assessments between images at 1:1 and 2:1 magnification (P < 0.05). The maximum variation in mean difference was 0.4% of actual object length for pins and 1.2% for spheres. The difference did not exceed 0.1 mm. R was lower for 2:1 magnification and consistently lower for spheres compared with pins.
The most reliable measurements were obtained of linear objects in the horizontal plane. Digital measurements are sufficiently accurate for clinical use.
评估数字化全景X线摄影术中数字测量的精度和准确性。
对一个干燥颅骨在七个不同位置进行一系列70次数字化全景X线摄影，在下颌骨上固定金属针和球体。由一名阅片者使用鼠标驱动光标在1:1和2:1放大倍数下进行三次重复测量。采用可靠性指数（R）和Malony/Rastogi检验评估精度，并通过配对Wilcoxon检验评估放大倍数对准确性的影响。
垂直测量的可重复性低于水平测量。1:1和2:1放大倍数下图像的评估存在显著差异（P < 0.05）。针的平均差异最大变化为实际物体长度的0.4%，球体为1.2%。差异不超过0.1毫米。2:1放大倍数下R较低，与针相比，球体的R始终较低。
在水平面中对线性物体进行测量最可靠。数字测量在临床上具有足够的准确性。
