连平,崇抗美,龚俊.应用灰阶率量化分析重建CT图像清晰度研究[J].中国医学影像技术,2003,19(9):
应用灰阶率量化分析重建CT图像清晰度研究
Quantitative Analysis of the Definition of Rebuilding CT Images Using the Grayscale-Rate
投稿时间:2003-03-13  
DOI:
中文关键词:  量化分析  图像清晰度  灰阶率
英文关键词:Quantitative analysis  Definition of image  Gray scale-rate
基金项目:
作者单位
连平 解放军第八五医院,上海 200052
全军远程医学研究开发基地 
崇抗美 解放军第八五医院,上海 200052 
龚俊 解放军第八五医院,上海 200052 
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中文摘要:
      目的 提高用于远程医疗之放射影像的质量和清晰度,提供医学影像重建的制作条件。方法 对42张CT片依片基分为两组进行复制,通过计算灰阶率分析图像清晰度和影响清晰度因素。结果 亮度值组间相差明显(P<0.01),组内三种分辨率间无显著差异。组间和组内分辨率间灰阶率无显著差异。两组亮度值与γ值均呈线性相关,灰阶率与γ值均呈曲线相关,H组曲线峰值段略落后于L组。组间最大灰阶率、信息损失率、最大灰阶率/最小γ值构成比无显著差异(P>0.05)。结论 扫描重建数字图像分辨率应选择两倍于屏幕频率,144ppi分辨率最适合远程医疗用,图像对比分辨阈值以γ值3.0最佳,有效范围不超出2.5至3.5为宜。利用灰阶率可评估重建数字图像的清晰度和扫描信息损失率。
英文摘要:
      Objective To improve the quality and definition of radiograph for telemedicine, and to master the preferences for rebuilding digital images. Methods Forty-two rebuilt CT films were divided into two groups upon the base, then the definition of images was analyzed by calculating the gray scale-rate. Results There existed significant difference between two groups on the brightness (P<0.01) and no difference in-group on the resolution. It was found that there is, linear correlation between the gamma value and the brightness, and curvilinear correlation between the gamma value and the gray scales-rate in both groups. The peak segment of the curve in group-H always goes a little behind that in group-L. There was no significant difference between two groups in term of the maximum gray scale-rate, the information loss-rate, and the composing of the max gray scale-rate and the minimum gamma value (P>0.05). Conclusion The scanning resolution used to rebuild images should double that of the display resolution. And 144ppi is the most suitable for radiograph film in teleconsultation. The most appropriate value of gamma is 3.0 with regard to the contrast resolution; the favorable range of gamma value is between 2.5 and 3.5. The definition and the information loss-rate of rebuilt images can be estimated by using gray scale-rate.
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