Dynamic Chest Radiography Matches Pulmonary Function Tests for COPD Diagnosis, Study Finds

A new study suggests that dynamic chest radiography may serve as a reliable alternative to pulmonary function testing (PFT) when diagnosing chronic obstructive pulmonary disease (COPD). The real-time X-ray technique not only offers comparable diagnostic performance, but also presents practical advantages in clinical settings where traditional tests may be limited.

Dynamic chest radiography captures continuous images of the lungs during respiration, allowing for a detailed view of lung and diaphragm movement as patients perform simple breathing maneuvers. With modern postprocessing technology, this method enables clinicians to visualize changes in lung area and diaphragm displacement in real-time.

“The technique is easy to operate, requiring only that the patient perform calm breathing and deep breathing maneuvers in front of the detector to obtain image data, and the radiation dose during this examination is comparable to that of conventional frontal and lateral chest radiography or low-dose chest CT examination,” wrote Laiyu Liu, MD, of the department of respiratory and critical care medicine at Nanfang Hospital, Southern Medical University, and colleagues. “[Dynamic chest radiography] postprocessing technology can provide precise tracking of diaphragm displacement in the respiratory cycle and can be used to quantitatively assess dynamic changes in lung projection area, providing multidimensional respiratory function parameters for clinical use.”

Traditionally, pulmonary function tests are used to measure forced expiratory volume and lung capacity. However, these tests require coordinated effort between patient and provider and became more difficult to administer during the COVID-19 pandemic due to the risk of aerosol transmission.

The researchers noted that dynamic chest radiography may provide many of the same insights as PFTs but with fewer operational hurdles. To explore this potential, they conducted a prospective analysis involving 553 individuals, both with and without COPD, between November 2022 and July 2024. Each participant completed both dynamic chest radiography and pulmonary function testing. Researchers used the results to create predictive models based on imaging, clinical data and patient characteristics.

They found strong correlations between parameters derived from the two modalities. In particular, the rate of change in lung area during deep breathing was significantly associated with forced expiratory volume in one second (FEV1) and the FEV1 to forced vital capacity ratio. A model based solely on dynamic chest radiography performed well in predicting COPD, but the most accurate results were achieved when imaging features were combined with smoking history.

These findings suggest that dynamic chest radiography may serve as an effective screening tool for COPD, especially in settings where pulmonary function testing is not feasible.

“Compared with traditional [pulmonary function tests], [dynamic chest radiography] overcomes the limitations of aerosol transmission and difficult operation, making DCR particularly suitable for the prevention of a high rate of missed diagnosis,” the authors wrote. “Unlike static imaging, DCR enables real-time visualization of lung and diaphragm kinetics and supports advanced postprocessing to generate functional ventilation and perfusion maps.”

While more research is needed to support widespread adoption, the authors believe dynamic chest radiography offers a promising, accessible path forward in the early detection of chronic lung disease.