| Popis: |
Background: Using planar gamma scintigraphy of inhaled radioaerosols, we have developed new analytical methods for assessing homogeneity of aerosol deposition and time-dependent particle clearance on a pixel-by-pixel basis, and applied them to a therapeutic cystic fibrosis (CF) study. Methods: At baseline and 1 month after beginning treatment with ivacaftor, a cystic fibrosis transmembrane regulator modulator for CF patients with at least one copy of the G551D mutation (n = 13), initial deposition and subsequent mucociliary clearance (MCC) of radiolabeled particles ( 99m Technetium-sulfur colloid, 5 μm mass median aerodynamic diameter) inhaled under controlled breathing conditions were measured. Results: Improved homogeneity of deposition, that is, decreased areas of higher and lower particle deposition in the lungs, was observed following ivacaftor treatment. The mean number ratio (NR) of pixels with higher deposition, relative to lung size, decreased from 0.14 to 0.09 (p = 0.003) and mean NR of colder pixels decreased from 0.23 to 0.19 (p = 0.004). Particle clearance was also improved following treatment, with mean MCC through 60 minutes equal to 12% versus 24%, without and with treatment, respectively (p = 0.010). Pixel-level analysis of MCC showed that (1) the fraction of pixels clearing >30% at 60 minutes was increased from 0.13 to 0.32 (p = 0.007); and (2) the fraction of pixels clearing |
