Figure 1.
Visualization of emphysema distribution in cystic fibrosis (CF) patients by chest MDCT density masks.
(A–G) Representative examples of morphologic images from non-enhanced multidetector computed tomography (MDCT) of the chest (left panels A, C, E) are complemented by density maps generated by dedicated software highlighting low attenuation areas below -950 Hounsfield units (HU) in yellow (right panels B, D, G). (A,B) MDCT image of a 36 year-old female CF patient with FEV1% = 48% showing bronchiectasis (A) as well as hypodense areas corresponding to emphysema (EI = 13.2%) mainly along subpleural and bronchovascular structures (B). (C,D) 38 year-old male CF patient with FEV1% = 29% with the lung parenchyma of the upper segments of the inferior lobes showing an overall hypodense texture and constricted vasculature (C). The density map shows extensive emphysema (EI = 24.0%) of both lungs with an emphasis on the lower lobes (D). (E–G) 46 year-old male cystic fibrosis patient (FEV1% = 55%) with marked bullous paraseptal emphysema of the right lung apex (black arrow) and centrilobular emphysema predominantly of both upper lobes (white arrowhead) (E). Note that these bullae do not possess walls differentiating them from cysts or sacculations (compare Figure S1). The minimum intensity projection (MinIP, 5 mm slice thickness) emphasizes emphysema visualization by accentuating low attenuation areas (F) with an overall EI of 18.0% (G).
Figure 2.
Quantification of emphysema in cystic fibrosis (CF) lung disease by densitometry.
(A–F) Box-and-whisker plots for lung volume (LV) (A), emphysema volume (EV) (B) and emphysema index (EI) (C), lung weight (LW) (D), mean lung density (MLD) (E) and 15th percentile of the lung density histogram (15th) (F) in the non-CF control group (CONTROL) and patients with CF. The central line represents the median, the box encompasses the 25th-75th percentiles, whiskers show 10th and 90th percentiles, and closed circles (•) represent individual outliers. * P<0.05, † P<0.01 and ‡ P<0.001 compared to CONTROL.
Figure 3.
Emphysema severity correlates with impairment in lung function in cystic fibrosis (CF).
(A–C) Dot plots with linear regression curves for emphysema index (EI) plotted against forced expiratory volume in 1 s percent predicted (FEV1%) (A), residual volume (RV) (B), and RV as ratio of total lung capacity (RV/TLC) (C) for patients with CF and the non-CF control group (CONTROL). Spearman rank order correlation coefficients (rs) are given for each plot. * P<0.05/7 (Bonferroni’s method, see Table 2).
Figure 4.
Emphysema progresses with age in cystic fibrosis (CF).
Dot plots with linear regression curves for emphysema index (EI) plotted against patient age for patients with CF and the non-CF control group (CONTROL). Spearman rank order correlation coefficients (rs) are given for each plot. Dashed curves indicate 95% confidence intervals. * P<0.001.