Sakai Shuji, Soeda Hiroyasu, Furuya Akio, Yabuuchi Hidetake, Okafuji Takashi, Yamamoto Keiji, Honda Hiroshi, Doi Kunio
Department of Health Sciences, School of Medicine, Kyushu University, 3-1-1, Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
J Digit Imaging. 2006 Dec;19(4):383-90. doi: 10.1007/s10278-006-0625-5.
The aim of the study is to evaluate the reliable production of temporal subtraction images in a picture archiving and communication system environment and to establish objective criteria for the evaluation of image quality. A total of 117 temporal subtraction chest images (55 in the upright position, 62 in the supine position) were obtained in five consecutive days. In all of these, we confirmed that there were no interval changes on the original images, and cases with diffuse lung disease were excluded. The temporal subtraction images were classified by three chest radiologists into five levels: 5, excellent; 4, good; 3, acceptable; 2, poor; and 1, very poor. The following were examined: (1) the yield of adequate quality of the temporal subtraction images; (2) whether the temporal subtraction images were obtained in the warping or nonwarping mode; and (3) the correlation of the overall subjective image quality with the relative shift angles, relative shift distances, and the standard deviation of gray levels in the temporal subtraction images. The percentages of acceptable temporal subtraction images were 100% and 66% in the upright and supine positions, respectively. Sixteen (26%) of the 62 supine-position images were made in nonwarping mode, whereas all upright images were made in warping mode. Significant correlations were obtained in the relative shift angle (P < 0.05), relative horizontal shift distance (P < 0.05), and standard deviation of gray levels (P < 0.0001). Temporal subtraction images with acceptable image quality were obtained in the upright position. The objective criteria may be useful for the evaluation of image quality.
本研究的目的是评估在图像存档与通信系统环境中可靠生成时间减影图像，并建立评估图像质量的客观标准。连续五天共获取了117张胸部时间减影图像（直立位55张，仰卧位62张）。在所有这些图像中，我们确认原始图像没有间隔变化，并排除了弥漫性肺部疾病的病例。三位胸部放射科医生将时间减影图像分为五个等级：5级，优秀；4级，良好；3级，可接受；2级，差；1级，非常差。检查了以下内容：（1）时间减影图像的合格质量产量；（2）时间减影图像是在扭曲模式还是非扭曲模式下获得的；（3）整体主观图像质量与时间减影图像中的相对移位角度、相对移位距离和灰度标准差之间的相关性。直立位和仰卧位可接受的时间减影图像百分比分别为100%和66%。62张仰卧位图像中有16张（26%）是在非扭曲模式下生成的，而所有直立位图像都是在扭曲模式下生成的。在相对移位角度（P < 0.05）、相对水平移位距离（P < 0.05）和灰度标准差（P < 0.0001）方面获得了显著相关性。在直立位获得了图像质量可接受的时间减影图像。这些客观标准可能有助于评估图像质量。
