TITLE:
Respiratory Changes in the Superior Vena Cava Area on Inspiratory and Expiratory Chest CT: Comparison between Patients with COPD and with Bronchial Asthma
AUTHORS:
Akiyuki Kotoku, Shin Matsuoka, Tsuneo Yamashiro, Shoichiro Matsushita, Atsuko Fujikawa, Hayato Tomita, Kunihiro Yagihashi, Yasuo Nakajima
KEYWORDS:
Computed Tomography, Hyperinflation, Hemodynamics, Intrathoracic Pressure, Expiration, COPD, Asthma
JOURNAL NAME:
Open Journal of Medical Imaging,
Vol.6 No.4,
December
14,
2016
ABSTRACT: Purpose: In patients with obstructive lung
diseases, alteration of intrathoracic pressure is closely related to hyperinflation
and leads to hemodynamic impairments. Both intrathoracic pressure and
hemodynamics are affected by the respiratory phase. In fact, a previous study
showed that respiratory phasic variations in the superior vena cava (SVC) area
significantly correlated with the extent of emphysema. Chronic obstructive
pulmonary disease (COPD) and bronchial asthma manifest different
pathophysiological changes in hyperinflation and hemodynamics. The current
study was conducted to evaluate differences in respiratory variations in the
cross-sectional area of the SVC between patients with COPD and with asthma.
Materials and Methods: We measured the SVC area and calculated the ratio of the
SVC area on inspiratory and expiratory scans (i/e-SVC ratio) in 66 patients with
COPD and 16 patients with asthma. The cor-relations of the i/e-SVC ratios with
airflow limitation, pulmonary small vessels less than 5 mm2 (%cross-sectional
area [%CSA] ﹣0.433, P = 0.003), i/e-LV ratio (ρ = ﹣0.371, P =
0.011), and percent of predicted forced expiratory volume in 1 second (FEV1%
predicted) (ρ = ﹣0.474, P = 0.001), whereas in asthma patients, there were no
significant correlations between the i/e-SVC ratio and those functional parameters.
Conclusion: There would be differences in the relationship between
intrathoracic pressure and cardiopulmonary hemodynamics between COPD and asthma
patients.