Halpern E J, Newhouse J H, Amis E S, Levy H M, Lubetsky H W
Department of Radiology, Columbia Presbyterian Medical Center, New York, NY 10032.
Radiology. 1989 Apr;171(1):259-63. doi: 10.1148/radiology.171.1.2928534.
The effect of a quadtree-based data-compression algorithm on the diagnostic yield in digitized radiographs was studied for 100 urograms. Each image was digitized and reviewed at nine decreasing compression ratios ranging from 90:1 to 4.2:1, followed by a review of the uncompressed digital images. Four radiologists independently reviewed the digitized images and the original radiographs and agreed on a reference standard of 201 findings. Sensitivity, measured by the number of findings noted on the compressed digital images, decreased with increasing compression ratios at and above the 11:1 level. No loss of sensitivity was noted with a compression ratio of 4.2:1. Sensitivity decreased more precipitously for calcifications than for soft-tissue masses. Only a minimal loss of sensitivity for bilateral renal function was noted, even with high compression ratios. False-positive rates were unaffected by compression. The authors conclude that quadtree compression ratios of 11:1 and higher may result in loss of sensitivity in clinically relevant findings.
对100份尿路造影数字化影像，研究了基于四叉树的数据压缩算法对诊断率的影响。将每张影像进行数字化处理，并以90:1至4.2:1的九个递减压缩比进行复查，随后复查未压缩的数字影像。四位放射科医生独立复查数字化影像和原始X光片，并就201项检查结果达成参考标准。以压缩数字影像上记录的检查结果数量衡量的敏感度，在11:1及以上的压缩比时，随压缩比增加而降低。压缩比为4.2:1时未发现敏感度损失。钙化的敏感度下降比软组织肿块更急剧。即使在高压缩比下，双侧肾功能的敏感度仅出现极小损失。假阳性率不受压缩影响。作者得出结论，11:1及更高的四叉树压缩比可能导致临床相关检查结果的敏感度损失。
