Teleradiology in dental panoramic images

这项研究由两部分组成。一是阐明分辨率和基于压缩胶片的数字化全景图像对诊断准确性的影响。二是评价数字全景成像系统在远程放射学中的应用。在第一部分中，将全景图像数字化并评估其诊断准确性。使用了两种类型的扫描仪：一种是专门制作的X线片扫描仪，另一种是常规扫描仪，分辨率分别为75和150dpi。图像压缩有四个级别：未压缩的TIFF格式和低、中、高压缩的JPEG格式。电子邮件附带的图像是使用14400 bps调制解调器传输的。结果表明：1)不同扫描仪之间有较小差异；2)空间分辨率在所用范围内影响相对较小；3)压缩对精度影响最大。结果表明，75或150dpi的低压缩JPEG文件适用于专用扫描仪，150dpi的低压缩JPEG文件适用于通用扫描仪。在第二部分中，将数字全景CCD系统c Digipan(Trophy，法国)安装在一个普通的全景单元(OP100，Instrumentan Finland)上。对患者获得的图像进行评估，以显示下颌骨、牙齿及其周围结构和上颌窦下缘的轮廓内部结构。对压缩后的JPEG图像也进行了评估。结果表明：1)mo*未压缩和压缩的图像对于一般诊断目的是可以接受的，并且*在1NS64上发送压缩文件所需的时间在1秒到20秒之间。结果表明，数字全景机在牙科远程放射学中可能会有用处。

The study consisted of two parts. One was to clarify the effects of the resolution and compression film-based digitized panoramic images on diagnostic accuracy. The other was to evaluate the applicat* of the digital panoramic imaging system to teleradiology. In the first part, the panoramic images wilt non-demarcated radiolucent lesions and without such lesions were digitized and evaluated on diagno accuracy. Two types of scanners were used : specially fabricated one for radiograph and the regular The resolution was 75 and 150 dpi. Image compression had four levels : the uncompressed TIFF format and the low, middle and high compressed JPEG format. The images attached to e-mail were transfered using 14400 bps modem. The results showed that I) there was a little difference between the scanner 2) the spatial resolution showed the relatively small effects in the range used, and 3) the compression had the critical effects on the accuracy. The results indicated that the low compressed JPEG file with resolution of 75 or 150 dpi was appropriate for a special scanner and the low compressed JPEG file' 150 dpi for a general purpose scanner. In the second part, the digital panoramic CCD system c Digipan (Trophy, France) was used attached to an ordinary panoramic unit (OP100, Instrumentan Finland). The images obtained from the patients were evaluated for the visibility of the contour internal structures of the mandible, the teeth and surrounding structures, and the lower border of maxillary sinus. The compressed JPEG images were also evaluated. The results showed that 1) mo* the uncompressed and compressed images were acceptable for the general diagnostic purposes, an* the time required to send the compressed file ranged between I and 20 seconds on 1NS64. The re* indicated that a digital panoramic machine could be useful for teleradiology in dentistry.