Tanaka Rie, Matsumoto Isao, Tamura Masaya, Takata Munehisa, Kasahara Kazuo, Ohkura Noriyuki, Inoue Dai, Matsuura Yukihiro
College of Medical, Pharmaceutical & Health Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 920-0942, Japan.
Department of Thoracic Surgery, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan.
Med Phys. 2020 Oct;47(10):4800-4809. doi: 10.1002/mp.14407. Epub 2020 Aug 5.
Dynamic chest radiography (DCR) is a flat-panel detector (FPD)-based functional lung imaging technique capable of measuring temporal changes in radiographic lung density due to ventilation and perfusion. The aim of this study was to determine the diagnostic performance of DCR in the evaluation of pulmonary function based on changes in radiographic lung density compared to nuclear medicine lung scans.
This study included 53 patients with pulmonary disease who underwent DCR and nuclear medicine imaging at our institution. Dynamic chest radiography was conducted using a dynamic FPD system to obtain sequential chest radiographs during one breathing cycle. The maximum change in the average pixel value (Δ ) was measured, and the percentage ofΔ in each lung region, calculated relative to the sum of all lung regions (Δ %), was calculated for each factor (ventilation and perfusion). The Δ % was compared with the accumulation of radioactive agents (radioactive agents%) on ventilation and perfusion scans in each lung and lung region using correlation coefficients and scatter plots. The ratio of ventilation to perfusion Δ % was calculated and compared with nuclear medicine ventilation-perfusion (V/Q) findings in terms of sensitivity and specificity for V/Q mismatch in each lung region.
There was a high correlation between Δ % and radioactive agents% for each lung (Ventilation: r = 0.81, perfusion: r = 0.87). However, correlation coefficients were lower (0.37 to 0.80) when comparing individual lung regions, with the upper lung regions showing the lowest correlation coefficients. The sensitivity and specificity of DCR for V/Q mismatch were 63.3% (19/30) and 60.1% (173/288), respectively. Motion artifacts occasionally increased Δ %, resulting in false negatives.
Ventilation and perfusion Δ % correlated reasonably with radioactive agents% on ventilation and perfusion scans. Although the regional correlations were lower and the detection performance for V/Q mismatch was not enough for clinical use at the moment, these results suggest the potential for DCR to be used as a functional imaging modality that can be performed without the use of radioactive contrast agents. Further technical improvement is required for the implementation of DCR-based V/Q studies.
动态胸部X线摄影（DCR）是一种基于平板探测器（FPD）的功能性肺成像技术，能够测量由于通气和灌注导致的胸部X线肺密度的时间变化。本研究的目的是确定与核医学肺扫描相比，基于胸部X线肺密度变化的DCR在评估肺功能方面的诊断性能。
本研究纳入了53例在我院接受DCR和核医学成像的肺部疾病患者。使用动态FPD系统进行动态胸部X线摄影，以在一个呼吸周期内获得连续的胸部X线片。测量平均像素值的最大变化（Δ），并针对每个因素（通气和灌注）计算每个肺区域的Δ相对于所有肺区域总和的百分比（Δ%）。使用相关系数和散点图将每个肺和肺区域的通气和灌注扫描中Δ%与放射性药物的积聚（放射性药物%）进行比较。计算通气与灌注Δ%的比值，并在每个肺区域V/Q不匹配的敏感性和特异性方面与核医学通气-灌注（V/Q）结果进行比较。
每个肺的Δ%与放射性药物%之间存在高度相关性（通气：r = 0.81，灌注：r = 0.87）。然而，在比较各个肺区域时，相关系数较低（0.37至0.80），上肺区域的相关系数最低。DCR对V/Q不匹配的敏感性和特异性分别为63.3%（19/30）和60.1%（173/288）。运动伪影偶尔会增加Δ%，导致假阴性。
通气和灌注Δ%与通气和灌注扫描中的放射性药物%具有合理的相关性。尽管区域相关性较低，且目前对V/Q不匹配的检测性能不足以用于临床，但这些结果表明DCR有潜力作为一种无需使用放射性对比剂即可进行的功能性成像方式。基于DCR的V/Q研究的实施需要进一步的技术改进。
