Dynamic MRI of Normal Diaphragmatic Motions during Spontaneous Breathing and Maximal Deep Breathing

Abstract

The purpose of this study was to quantitatively analyze differences in normal diaphragmatic motions during spontaneous breathing (SB) and maximal deep breathing (MDB) using dynamic analysis of magnetic resonance imaging (dynamic MRI), to examine whether there is correlation between total diaphragmatic motion during MDB and BMI, vital capacity (VC), and chest expansion. Mean cephalocaudal distance in diaphragmatic motion was 14 mm in the ventral region, 20 mm in the central region, 27 mm in the dorsal region during SB, and 41 mm in the ventral region, 64-67 mm in the central region, and 74 mm in the dorsal region during MDB. No correlation was apparent between total diaphragmatic motion during MDB and BMI, VC, or chest expansion.

The effect of different body positions on the cardiothoracic ratios obtained by chest radiography in Japanese macaques (Macaca fuscata) and rhesus macaques (Macaca mulatta)

“…This may be one of the reasons for the maximum HW being significantly smaller and the maximum TH being significantly greater in the sitting position than in the prone position. Additionally, the reason why HW was significantly shorter, and TW did not change significantly in the sitting position can be explained by the movement of the thorax, which is observed to be greater in the vertical direction than in the horizontal direction in Japanese and rhesus macaques, as reported in humans 40 . In the medical and veterinary fields, the evaluation of intrathoracic organs using chest radiography is generally performed in a state of inspiration to increase the size of the lung field and improve diagnostic accuracy 29,41 .…”

“…According to the report, the change in longitudinal lung diameter was negatively correlated with the change in transverse heart diameter during expiration and inspiration. In humans, it has been reported that the diaphragm rises approximately 6 cm more during exhalation than during inhalation and that the vertical movement of the thorax is greater than the horizontal 40 . When the diaphragm drops vertically, the heart becomes thinner and longer.…”

Changes in Cross-Sectional Area and Transverse Diameter of the Heart on Inspiratory and Expiratory Chest CT: Correlation with Changes in Lung Size and Influence on Cardiothoracic Ratio Measurement

“…Although it is very difficult to explain the larger cardiac CSA or CTR measurements on expiratory based on CT, the following explanation would be plausible: During respiration, muscle contractions or reflections of the diaphragm and external intercostal muscles dramatically change the shapes of the thorax and heart. A previous report showed that the diaphragm is elevated by 6 cm vertically between a full inspiration and expiration, and that vertical movement of the thorax was significantly larger than transverse movement of the thorax [ 22 ]. When the diaphragm is dislocated downward during inspiration, the heart becomes narrower and elongated.…”

“…Conversely, during expiration, the heart becomes wider and shorter; the left side rotates dorsally and laterally. The cardiac long axis leans in a transverse direction due to elevation of the diaphragm [ 12 , 22 ]. Since the superior and inferior vena cava anchor the right atrium, the movement of the right ventricle during respiration is more limited than that of the left ventricle [ 12 ].…”

Lymphatic Stomata in the Adult Human Pulmonary Ligament

“…For example, the mean cephalocaudal distances during motion of the central portion of the diaphragm where the lower portion of the pulmonary ligament is attached are approximately 20.6 mm during spontaneous breathing and 64.2 mm during maximal deep breathing in healthy younger adults. 40 Several investigators have speculated that back-flow from the lymphatic stomata into the serosal cavity is prevented by minute overlapping of mesothelial and endothelial cells according to serosal membrane movement that is synchronously coordinated during breathing; [41][42][43] whether this cellular overlapping in the lymphatic stomata can efficiently prevent regurgitation against these dynamic changes remains to be determined. Because not all of the stomata we observed were equipped with flap valve-related cytoplasmic processes, some of the flow via the stomata is potentially bidirectional.…”