Department of Radiological Technology, School of Health Sciences, College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa 920-0942, Japan.
Int J Comput Assist Radiol Surg. 2011 Jan;6(1):103-10. doi: 10.1007/s11548-010-0491-y. Epub 2010 Jun 13.
Decreased ventilation is observed on chest radiographs as small changes in X-ray translucency, and ventilatory impairments can therefore be detected by analyzing the distribution of respiratory-induced changes in pixel value. This study was performed to develop a ventilatory impairment detection method based on the distribution of respiratory-induced changes in pixel values.
Sequential chest radiographs during respiration were obtained using a dynamic flat panel detector system. Respiratory-induced changes in pixel value were measured in each local area and then compared for symmetrical positions in both lungs, which were located at the same distance from the axis of the thorax at the same level. The right-left symmetry was assessed in 20 clinical cases (Abnormal, 14; Normal, 6).
In normal controls, the distribution was symmetrical, and there were good correlations of the pixel value changes in both lungs at symmetrical positions (r = 0.66 ± 0.05). In contrast, abnormal cases did not show a symmetrical distribution of pixel value changes (r = 0.40 ± 0.23) due to ventilation abnormalities observed as reductions in pixel value changes.
Ventilatory impairment could be detected as deviation from the right-left symmetry of respiratory-induced changes in pixel value. In particular, the present method could be useful for detecting unilateral abnormalities. However, to detect bilateral abnormalities, further studies are required to develop multilevel detection methods combined with several methods of pattern analysis.
在胸部 X 光片中，通气减少表现为 X 射线透明度的微小变化，因此可以通过分析像素值呼吸诱导变化的分布来检测通气障碍。本研究旨在开发一种基于像素值呼吸诱导变化分布的通气障碍检测方法。
使用动态平板探测器系统获取呼吸过程中的连续胸部 X 光片。测量每个局部区域的像素值呼吸诱导变化，然后比较两侧肺相同距离和相同水平的对称位置。对 20 例临床病例（异常 14 例，正常 6 例）进行左右对称性评估。
在正常对照组中，分布是对称的，对称位置的双肺像素值变化具有良好的相关性（r = 0.66 ± 0.05）。相比之下，由于观察到的通气异常导致像素值变化减少，异常病例的像素值变化没有显示出对称的分布（r = 0.40 ± 0.23）。
可以通过偏离像素值呼吸诱导变化的左右对称性来检测通气障碍。特别是，本方法对于检测单侧异常可能是有用的。然而，要检测双侧异常，需要进一步研究，开发结合几种模式分析方法的多层次检测方法。
