Zhou Luyi, Su Xianyu, Qin Weishi, Li Lin, Kuang Anren, Mo Tingshu
Department of Nuclear Medicine, West China Hospital, Sichuan University, Chengdu, China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2006 Feb;23(1):52-5.
To study the usefulness of JPEG2000 compression for nuclear medicine (NM) image, normal and abnormal static images were compressed using a JPEG2000 plug-in. For lossless algorithm, the compressing ratio (CR) was calculated. For lossy algorithm, images were visually analyzed by NM physicians and ROC curves were generated. The area under ROC curve (AUC) was used as the index of image diagnostic quality. Paired sample t tests were performed to compare the AUCs. It was found that the lossless CR was (1.34+/-0.05) : 1. For lossy algorithm, the AUC decreased with the increase of CR. Comparison between the original and the compressed images revealed no significant difference for 10:1 CR but significant difference for bigger CRs. It was concluded that lossless compression has little usefulness for NM image because of very low CR. While lossy compression isused, the diagnostic quality of static NM images is preserved at CRs 50 : 1,40 : 1, 30 : 1,20 : 1 up to 10 : 1. For other types of NM image, CR should be increased or decreased according to their characteristics, especially the level of intrinsic statistical noise of NM image.
为研究JPEG2000压缩技术对核医学（NM）图像的有效性，使用JPEG2000插件对正常和异常静态图像进行压缩。对于无损算法，计算压缩比（CR）。对于有损算法，由核医学医生对图像进行视觉分析并生成ROC曲线。以ROC曲线下面积（AUC）作为图像诊断质量指标，采用配对样本t检验比较AUC。结果发现，无损压缩比为（1.34±0.05）:1。对于有损算法，AUC随压缩比增加而降低。原始图像与压缩图像比较显示，压缩比为10:1时无显著差异，而压缩比更大时则有显著差异。研究得出结论，由于压缩比极低，无损压缩对核医学图像用处不大。而采用有损压缩时，静态核医学图像在压缩比为50:1、40:1、30:1、20:1直至10:1时仍能保持诊断质量。对于其他类型的核医学图像，应根据其特征，特别是核医学图像的固有统计噪声水平，来增减压缩比。
