Savcenko V, Erickson B J, Palisson P M, Persons K R, Manduca A, Hartman T E, Harms G F, Brown L R
Department of Diagnostic Radiology, Mayo Foundation, Rochester, MN 55905, USA.
Radiology. 1998 Mar;206(3):609-16. doi: 10.1148/radiology.206.3.9494474.
To assess the effect of wavelet-based compression of posteroanterior chest radiographs on detection of small uncalcified pulmonary nodules and fibrosis.
Computed tomography (CT) of the chest was used to identify 20 patients with normal posteroanterior chest radiographs, 20 with a solitary uncalcified pulmonary nodule 1-2 cm in diameter, and 20 with fibrotic disease. A double-blind protocol for readings of original images and images compressed at 40:1 and 80:1 was analyzed by using the nonparametric receiver operating characteristic to measure differences in diagnostic accuracy and their statistical significance.
There was no substantial difference in the overall diagnostic accuracy (measured by the area under the curve index) for both nodules and fibrosis between images compressed at 40:1 and 80:1 and uncompressed images. Readers tended to perform better on images compressed at 40:1 compared with uncompressed images. The "high-sensitivity" portion of the 80:1 compression curve for nodules was below that for the uncompressed curve, although this was not statistically significant.
Lossy compression of chest radiographs at 40:1 can be used without decreased diagnostic accuracy for detection of pulmonary nodules and fibrosis. There is no statistically significant difference in diagnostic accuracy at 80:1 compression, but detection ability is decreased.
评估基于小波的后前位胸部X线片压缩对小的未钙化肺结节及纤维化检测的影响。
采用胸部计算机断层扫描（CT）来确定20例后前位胸部X线片正常的患者、20例有直径1 - 2 cm的孤立未钙化肺结节的患者以及20例有纤维化疾病的患者。通过使用非参数接收器操作特性来分析原始图像以及以40:1和80:1压缩的图像的双盲读片方案，以测量诊断准确性的差异及其统计学意义。
对于结节和纤维化，在以40:1和80:1压缩的图像与未压缩图像之间，总体诊断准确性（通过曲线下面积指数测量）没有实质性差异。与未压缩图像相比，阅片者在以40:1压缩的图像上表现往往更好。对于结节，80:1压缩曲线的“高敏感性”部分低于未压缩曲线，尽管这在统计学上不显著。
胸部X线片以40:1进行有损压缩可用于检测肺结节和纤维化，且诊断准确性不会降低。在80:1压缩时，诊断准确性没有统计学上的显著差异，但检测能力有所下降。
