Researchers at Kyushu University have reported that a seven-second Dynamic Chest Radiography (DCR) scan may help assess pulmonary valve regurgitation (PR) in patients who have undergone repair of Tetralogy of Fallot (TOF), according to findings published in Radiology.

TOF is the most common cyanotic congenital heart defect, affecting roughly one in 3,500 newborns. While survival rates have improved significantly following surgical repair, many patients develop PR, a condition in which blood leaks backward through the pulmonary valve. Monitoring disease severity is important because untreated severe PR can increase the risk of serious cardiac complications.

Cardiac MR is considered the standard method for quantifying PR, but access can be limited by cost, equipment availability and patient factors, including incompatible implanted devices or claustrophobia.
The Kyushu University team evaluated whether DCR, an imaging technique that uses conventional X-ray equipment to capture a sequence of chest images during a breath hold, could provide an alternative assessment tool. Rather than relying solely on visual interpretation, investigators analyzed changes in pixel values within the pulmonary arteries over time and converted those measurements into waveforms reflecting blood flow dynamics.

The study included 58 patients who had undergone surgical repair of TOF and 14 healthy volunteers. Researchers found that the technique identified severe PR with 93% accuracy, including 93% sensitivity and 94% specificity.

“DCR images are usually assessed visually. However, for this study, we analyzed temporal changes in pixel values over the pulmonary arteries in captured sequential images,” said Yuzo Yamasaki, assistant professor at the Kyushu University Hospital Radiology Center and first author of the study. “These changes were converted into waveforms, allowing us to quantify blood flow dynamics.”

The scan requires a seven-second breath hold and does not require contrast agents. Researchers reported a radiation dose of approximately 0.2 mSv, substantially lower than a typical chest CT scan.

The authors said additional multicenter studies are planned to validate the findings and determine whether DCR could play a broader role in routine evaluation of congenital heart disease patients and other cardiovascular conditions.

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