Pulmonary regurgitation diagnosed via x-ray in 7 seconds

A research group including Assistant Professor Yuzo Yamasaki of the Department of Radiology at Kyushu University Hospital, Professor Kousei Ishigami of the Department of Clinical Radiology at the Graduate School of Medical Sciences, Kyushu University, Associate Professor Kenichiro Yamamura of the Comprehensive Maternity and Perinatal Care Center at Kyushu University Hospital, Specially Appointed Assistant Professor Ichiro Sakamoto of the Department of Cardiovascular Medicine at Kyushu University Hospital (at the time of the research), and Engineer Ryoichi Watanabe of Konica Minolta has developed the world's first system to quantitatively evaluate the severity of pulmonary regurgitation. The system uses a new approach that extracts and analyzes changes in pulmonary artery pixel values obtained via dynamic chest radiography (DCR) as a "waveform." The findings were published in Radiology.

An image of the newly developed system.Provided by Kyushu University Tetralogy of Fallot is a congenital heart disease characterized by a tetrad of features: ventricular septal defect, pulmonary stenosis, overriding aorta, and right ventricular hypertrophy, occurring with a frequency of 1 in 3,500 births. It is the most common cyanotic congenital heart disease and requires corrective surgery during childhood, but reoperation is often necessary in adulthood.

Whether this is required is indicated in guidelines by the regurgitation fraction of pulmonary regurgitation (PR). While echocardiography (cardiac ultrasound) is simple, it remains a qualitative evaluation with substantial variation between observers. Cardiac MRI allows for the most accurate quantitative evaluation, but it faces issues such as limited available facilities and high examination costs.

The research group focused on DCR. By taking images at 15 frames per second while the patient holds their breath for 7 seconds, changes in X-ray permeability over time are expressed as increases or decreases in blood volume. Yamasaki stated, "While discussing the principles of imaging, I thought that information on PR might be contained within the blood flow changes and conceived this method for quantitative evaluation."

In a verification study targeting 58 postoperative tetralogy of Fallot patients and 14 healthy volunteers, the index obtained from the system (the slope of the wave derived from waveform analysis) showed an extremely high correlation with the regurgitation fraction measured by cardiac MRI. Furthermore, in detecting severe pulmonary regurgitation (regurgitation fraction >30%), it achieved an excellent diagnostic performance with a sensitivity of 93%, a specificity of 94%, an overall diagnostic accuracy of 93%, and an AUC of 0.98.

Because the radiation dose is also extremely low and it can be performed in a general X-ray room, it is expected to function as a simple and patient-friendly screening test to determine the necessity of a cardiac MRI exam in cases where severity determination is difficult with cardiac ultrasound. It will also serve as an alternative for patients who cannot undergo cardiac MRI due to claustrophobia or pacemaker implantation. In the future, the group is considering multi-center collaborative studies and expansion to other diseases.

Journal Information Publication: Radiology Title: Novel Dynamic Chest Radiography Technique for Assessing Pulmonary Regurgitation in Repaired Tetralogy of Fallot DOI: 10.1148/radiol.252344 Medicine This article has been translated by JST with permission from The Science News Ltd.

(https://sci-news.co.jp/).

Unauthorized reproduction of the article and photographs is prohibited. This article has been translated by JST with permission from The Science News Ltd. (https://sci-news.

co.jp/). Unauthorized reproduction of the article and photographs is prohibited.