X-ray Darkfield Chest Radiography: Correlation of First Results from COPD-Patients with Lung Function Tests

Abstract

Introduction: Chest X-rays are of limited use as a screening tool for emphysema. Grating-based X-ray dark-field (XDF) imaging may provide a potential solution by indirectly visualizing the microstructure of the lung. In a first patient study, we are investigating the use of XDF imaging for the detection of COPD. Here, we report on the correlation of dark-field signal strength to results from lung function tests.

Methods and Materials: In this ongoing prospective clinical study 54 of 500 adult study participants (250 patients with COPD and 250 patients without lung diseases) have been included (17 females, mean age 61±11 years; 37 males, mean age 67±12 years). Dark-field chest X-rays are acquired using a grating-based prototype imaging setup operating at 70 kVp in a scanning mode. As a reference, conventional chest X-rays, CT-scans, whole-body plethysmography and a COPD assessment test are performed. Visual assessment of XDF strength using a 6-point ordinal scale was performed by three independent readers and XDF signal strength was quantitatively evaluated. The results were correlated with findings of lung function tests.

Results: Both objective and subjective XDF strength showed a significant correlation with the Tiffeneau-Pinelli index (FEV1/FVC), and with FEV1 as percent of predicted.

Conclusion: XDF signal strength may serve as a diagnostic marker of pulmonary function in COPD by visualizing structural changes of the lung parenchyma. As a novel imaging modality, XDF radiography has the potential to facilitate early diagnosis of COPD, while requiring less patient cooperation than spirometry at a much lower radiation exposure than CT scans.