Halpern E J, Levy H M, Newhouse J H, Amis E S, Sanders L M, Mun I K
Department of Radiology, Columbia Presbyterian Medical Center, New York, NY 10032.
Invest Radiol. 1990 Jan;25(1):31-8. doi: 10.1097/00004424-199001000-00009.
An ROC study was performed to evaluate the effect of quadtree-based data compression on the diagnostic yield of CT images. Seventy images were selected from a series of consecutive abdominal/pelvic CT scans. Following the application of quadtree-based compression, all images were reviewed independently by three radiologists. The images were analyzed at six decreasing irreversible compression ratios (30.6:1 to 7.4:1), as well as after reversible compression (2.9:1). ROC curves reveal a gradual decrease in clinical accuracy with increasing compression ratios. At a compression ratio of 7.4:1, sensitivity for all major abnormalities was 99% with a specificity of 93%. As the compression ratio was increased to 30.6:1, sensitivity and specificity dropped to 75% and 83% respectively. Execution times for compression and decompression of the CT images with a PC-AT based digital radiography system varied from 24.7 to 18.5 seconds and from 16.2 to 5.1 seconds respectively, decreasing with higher levels of compression. We conclude that quadtree-based compression of abdominal CT images may have practical applications for a PC based digital radiography system.
进行了一项ROC研究，以评估基于四叉树的数据压缩对CT图像诊断率的影响。从一系列连续的腹部/盆腔CT扫描中选取了70幅图像。在应用基于四叉树的压缩之后，由三位放射科医生独立审查所有图像。以六种逐渐降低的不可逆压缩比（30.6:1至7.4:1）以及可逆压缩（2.9:1）之后对图像进行分析。ROC曲线显示，随着压缩比增加，临床准确性逐渐降低。在压缩比为7.4:1时，对所有主要异常的敏感性为99%，特异性为93%。当压缩比增加到30.6:1时，敏感性和特异性分别降至75%和83%。使用基于PC-AT的数字射线摄影系统对CT图像进行压缩和解压缩的执行时间分别从24.7秒至18.5秒以及从16.2秒至5.1秒不等，随着压缩水平的提高而减少。我们得出结论，基于四叉树的腹部CT图像压缩对于基于PC的数字射线摄影系统可能具有实际应用价值。
