Abstract
Introduction: Hyperpolarised (HP) gas MRI is sensitive to early lung ventilation heterogeneity in cystic fibrosis (CF) children. However, little is known if changes in lung microstructure accompany the disease progression. HP gas diffusion-weighted (DW) MRI has been shown to be a technique sensitive to changes in lung microstructure at the acinar level.
Aims: Compare 3He DW-MRI metrics of lung microstructure in children with mild CF and healthy controls (HC) at baseline, and to reassess the CF cohort after 2-years.
Methods: 19 children with CF and normal spirometry (FEV1 z-score> -2), and 10 HC were assessed with HP 3He DW-MRI. 14 of the CF cohort were reassessed after 2-years. Apparent diffusion coefficient (ADC) and estimates of alveolar dimension (LmD) were calculated at each visit, and compared to previously reported ventilation defect percentage (VD%) values in the same cohort [Smith, L., et al. (2016). ERJ 48].
Results: No significant difference in mean ADC and LmD was observed between HC and CF children. In contrast, VD% was significantly larger (p<0.001) in CF children (Figure 1a). After 2 years, children with CF did not have a significant change in ADC and LmD; despite a significant increase in VD% (p=0.002) (Figure 1b).
Conclusion: 3He DW-MRI suggests that no acinar microstructural changes occur in the ventilated regions of early CF lung disease despite increases in ventilation heterogeneity.
- Copyright ©the authors 2017