England Gregory M, Moon Eun-Sang, Roth Jordan, Deguchi Toru, Firestone Allen R, Beck F Michael, Kim Do-Gyoon
1 Division of Orthodontics, College of Dentistry, Ohio State University, Columbus, OH, USA.
2 Division of Oral Bioscience, College of Dentistry, Ohio State University, Columbus, OH, USA.
Dentomaxillofac Radiol. 2017 Feb;46(2):20160322. doi: 10.1259/dmfr.20160322. Epub 2016 Nov 15.
The objective of the present study was to examine the grey value parameters and their magnitudes produced by CBCT and whether they are influenced by different scanners with various scanning conditions.
An ATOM Max dental and diagnostic artificial head was scanned by two CBCT scanners (Planmeca and iCAT). Under full field of view with normal dose and ultralow-dose (ULD) conditions, the Planmeca scanner was examined for three scanning resolutions (200, 400, and 600 micron voxel sizes) and the iCAT scanner was tested for four scanning resolutions (200, 250, 300 and 400 micron voxel sizes). After 9 weeks, the artificial head was scanned again by the Planmeca scanner with the same scanning conditions. In addition, two hydroxyapatite phantoms (1220 and 1540 mg cm) were adhered on the artificial head and scanned using normal and ULD scanning conditions of 400 micron voxel size with both scanners. The grey value histogram of each region, which is proportional to the bone mineral density (BMD) histogram, was utilized to determine grey value distribution parameters and compare scanners (ANOVA, p < 0.05).
The different scanning conditions and the bilateral locations of the artificial head did not have significant effects on measurements of the grey value parameters (p > 0.436) with excellent repeatability. However, the iCAT scanner produced significantly different grey values from the Planmeca scanner (p < 0.001).
CBCT can assess BMD, while calibration of absolute measures is necessary to obtain comparable values between different scanners that are currently used to assess oral bone quantity and quality.
本研究的目的是检查锥形束计算机断层扫描（CBCT）产生的灰度值参数及其大小，以及它们是否受到具有不同扫描条件的不同扫描仪的影响。
使用两台CBCT扫描仪（普兰梅卡和i-CAT）对一个ATOM Max牙科诊断仿真头模进行扫描。在全视野、正常剂量和超低剂量（ULD）条件下，对普兰梅卡扫描仪进行三种扫描分辨率（体素大小为200、400和600微米）的检测，对i-CAT扫描仪进行四种扫描分辨率（体素大小为200、250、300和400微米）的检测。9周后，使用相同的扫描条件，再次由普兰梅卡扫描仪对仿真头模进行扫描。此外，将两个羟基磷灰石体模（1220和1540 mg/cm）粘贴在仿真头模上，并使用两台扫描仪在体素大小为400微米的正常和ULD扫描条件下进行扫描。利用与骨密度（BMD）直方图成比例的每个区域的灰度值直方图来确定灰度值分布参数并比较扫描仪（方差分析，p<0.05）。
不同的扫描条件和仿真头模的双侧位置对灰度值参数测量没有显著影响（p>0.436），重复性良好。然而，i-CAT扫描仪产生的灰度值与普兰梅卡扫描仪有显著差异（p<0.001）。
CBCT可以评估骨密度，然而，为了在目前用于评估口腔骨量和质量的不同扫描仪之间获得可比的值，需要对绝对测量值进行校准。
