AcknowledgmentsThe authors acknowledge the valuable assistance of Hideo Ogata, MD, PhD, Norihisa Motohashi, MD, PhD, Misako Aoki, MD, Yuka Sasaki, MD, PhD, and Hajime Goto, MD, PhD, from the Department of Respiratory Medicine; Yuji Shiraishi, MD, PhD, from the Department of Respiratory Surgery; and Masamitsu Ito, MD, PhD, Atsuko Kurosaki, MD, Yoichi Akiyama, RT, Kenta Amamiya, RT, and Kozo Hanai, RT, PhD, from the Department of Radiology, Fukujuji Hospital, for their important suggestions. The authors also acknowledge the valuable assistance of Alba Cid, MS, for editorial work on the manuscript. Yoshitake Yamada, MD, PhD, is a recipient of a research fellowship from the Uehara Memorial Foundation.
Appendix. Supplementary DataThe following is the supplementary data to this article:
A representative video of sequential chest radiographs obtained by chest dynamic radiography for the motion of the diaphragms (“dynamic X-ray phrenicography”). A board-certified radiologist placed a point of interest (red point) on the highest point of each tryptophan hydroxylase
on the radiograph at the resting end-expiratory position. These points were automatically traced by the template-matching technique throughout the respiratory phase. Based on locations of the points on sequential radiographs, the vertical excursions and the peak motion speeds of the bilateral diaphragm were calculated (Fig 2c).Help with MP4 filesOptionsDownload video (1042 K)
Multivariate analysis of associations between the excursions and participant demographics using age, gender, BMI, tidal volume, VC, FEV1, and smoking history as factors (Model 2).Help with DOCX filesOptionsDownload file (23 K)
The bilateral diaphragm is the most important respiratory muscle. Diaphragmatic dysfunction is an underappreciated cause of respiratory difficulties and may be due to a wide variety of issues, including surgery, trauma, tumor, and infection (1). Several previous studies have evaluated diaphragmatic motion using fluoroscopy 2; 3; 4 ; 5, ultrasound 6 ; 7, magnetic resonance (MR) fluoroscopy (dynamic MR imaging [MRI]) 8; 9; 10; 11 ; 12, and computed tomography (CT) 13; 14; 15 ; 16. However, the data of the previous studies using ultrasound, MR fluoroscopy, or CT were obtained in a supine position 6; 7; 8; 9; 10; 11; 12; 13; 14; 15 ; 16, not in a standing position. Also, while the data of the previous studies using fluoroscopy were obtained in a standing position, the data were assessed under forced breathing 2 ; 3, not under tidal or resting breathing. Thus, diaphragmatic motion in a standing position during tidal breathing remains unclear, even though it is e
ssential for understanding respiratory physiology in our daily life. Furthermore, the evaluation of diaphragmatic motion
using fluoroscopy, ultrasound, dynamic MRI, or CT has not been used as a routine examination because of limitations, including high radiation
dose, small field of view, low temporal resolution, and/or high cost.
Recently, dynamic chest radiography using a flat panel detector (FPD) system with a large field of view was introduced for clinical use. This technique can provide sequential chest radiographs with high temporal resolution during respiration (17), and the radiation dose is much lower than that of CT. Also, whereas CT and MRI are performed in the supine or prone position, dynamic chest radiology can be performed in a standing or sitting position, which is physiologically relevant. To the best of our knowledge, no detailed study has analyzed diaphragmatic motion during tidal breathing by using dynamic chest radiography.