This study evaluated the respiratory motion of the lung parenchyma using dynamic magnetic resonance imaging and clarified differences between healthy individuals and patients with chronic obstructive pulmonary disease (COPD).
The study comprised 6 healthy volunteers and 42 patients diagnosed with smoking-related COPD. We captured 80 sequential frames from the mid-sagittal portion of the right lung while repeating forced deep breathing using a balanced fast-field echo sequence (repetition time, 2.2 ms; echo time, 1.1 ms; slice thickness, 10 mm; field of view, 450 mm; matrix size, 128×256; and acquisition time, 0.28 s/frame). We traced 15 points on pulmonary vessels using a computer-aided system and measured the maximal motion distance of each tracked point. Movement of these points was then compared with spirometric data using the Pearson correlation coefficient.
Patients with COPD showed reduced respiratory motion compared with healthy volunteers. Respiratory motion and spirometric data such as forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity showed highly significant positive correlations (correlation between normalized motion distance for the whole lung and FEV1, r=0.75; P<0.01).
The respiratory motion of the pulmonary vessels reflects expansion and deflation of the lung parenchyma, and such motion is restricted in patients with COPD due to airflow limitation.
*Department of Radiology, Yokohama City University Graduate School of Medicine
Departments of †Radiology
§Respiratory Medicine, Kanagawa Cardiovascular and Respiratory Center
‡Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama, Japan
The authors declare no conflicts of interest.
Supported by the global center of excellence program Japan Society for the Promotion of Science Fund and the Kanagawa Cancer Research Fund.
Reprints: Hirofumi Shibata, MD, Department of Radiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan (e-mail: email@example.com).