Correlations between forced oscillation technique parameters and pulmonary densitovolumetry values in patients with acromegaly

Abstract

The aims of this study were to evaluate the forced oscillation technique (FOT) and pulmonary densitovolumetry in acromegalic patients and to examine the correlations between these findings. In this cross-sectional study, 29 non-smoking acromegalic patients and 17 paired controls were subjected to the FOT and quantification of lung volume using multidetector computed tomography (Q-MDCT). Compared with the controls, the acromegalic patients had a higher value for resonance frequency [15.3 (10.9-19.7) vs 11.4 (9.05-17.6) Hz, P=0.023] and a lower value for mean reactance [0.32 (0.21-0.64) vs 0.49 (0.34-0.96) cm H2O/L/s2, P=0.005]. In inspiratory Q-MDCT, the acromegalic patients had higher percentages of total lung volume (TLV) for nonaerated and poorly aerated areas [0.42% (0.30-0.51%) vs 0.25% (0.20-0.32%), P=0.039 and 3.25% (2.48-3.46%) vs 1.70% (1.45-2.15%), P=0.001, respectively]. Furthermore, the acromegalic patients had higher values for total lung mass in both inspiratory and expiratory Q-MDCT [821 (635-923) vs 696 (599-769) g, P=0.021 and 844 (650-945) vs 637 (536-736) g, P=0.009, respectively]. In inspiratory Q-MDCT, TLV showed significant correlations with all FOT parameters. The TLV of hyperaerated areas showed significant correlations with intercept resistance (rs=−0.602, P<0.001) and mean resistance (rs=−0.580, P<0.001). These data showed that acromegalic patients have increased amounts of lung tissue as well as nonaerated and poorly aerated areas. Functionally, there was a loss of homogeneity of the respiratory system. Moreover, there were correlations between the structural and functional findings of the respiratory system, consistent with the pathophysiology of the disease.

Computed tomography airway lumen volumetry in patients with acromegaly: Association with growth hormone levels and lung function

“…There is growing interest in using FOT to assess lung function because the measurements are taken during spontaneous breathing; the technique provides new reactive and resistive parameters for understanding ventilation mechanics, and the parameters provided by FOT present a good correlation with the findings from CT scans . We observed that Rm (which is associated with airway calibre) was higher in patients with acromegaly than in the controls.…”

“…4 There is growing interest in using FOT to assess lung function because the measurements are taken during spontaneous breathing; the technique provides new reactive and resistive parameters for understanding ventilation mechanics, and the parameters provided by FOT present a good correlation with the findings from CT scans. 6,12 We observed that Rm (which is associated with airway calibre) was higher in patients with acromegaly than in the controls. We also observed a negative correlation between the Rm obtained through FOT and the tracheal equivalent diameter, RMB and LMB measures obtained through CT, indicating that tracheal geometry abnormalities propagate throughout the structure of the lower airways in patients with acromegaly.…”

“…Among the 40 patients with acromegaly initially recruited, 12 were excluded for the following reasons: refusal to participate in the study (6) and inability to undergo PFT (6). Among the study participants with acromegaly, 10 presented active disease and 18 showed controlled disease.…”

“…The advent of multislice CT brought significant advances in imaging diagnosis in all fields of medicine. In addition, using imaging analysis programmes, it is possible to estimate lung volumes and correlate them with classic tools for the measurement of lung function . Similar investigations using CT airway volumetry are more limited, although some recent studies have shown promising results .…”

“…In addition, using imaging analysis programmes, it is possible to estimate lung volumes and correlate them with classic tools for the measurement of lung function. 6 Similar investigations using CT airway volumetry are more limited, although some recent studies have shown promising results. [7][8][9] This technique has also been applied in obstructive diseases that are potentially damaging to the airways.…”