118 Antibiotic regimen changes during pediatric pulmonary exacerbation treatment

Methods: Children with CF aged 6 to 11 were recruited from three CF centers (Indiana University, University of Michigan, Case Western Reserve University).MBW was performed according to published guidelines, and lung clearance index (LCI) was measured.Chest CT was scored using the Brody score.Lung T1-MRI images were acquired using a Modified Look-Locker Imaging acquisition with a short echo time (∼10 seconds/imaging slice).Lung T1 maps were thresholded to calculate percentage normal lung perfusion (%NLP) for each subject.Descriptive statistics were used to analyze the cohort, and Pearson or Spearman correlations were used to study the association between T1-MRI%NLP, LCI, and Brody score, and p ≤0 .05 was considered significant.Results: Forty-five children had acceptable T1-MRI, MBW, and CT data.Their clinical and test data are summarized in Table .T1-MRI%NLP correlated significantly with CT scores (R = -0.41,p = 0.03) but not LCI (R = -0.06,p = 0.71).LCI and CT scores were significantly correlated (R = 0.43, p = 0.02).Analysis of correlations with Brody subscores showed that LCI correlated significantly with air trapping, peribronchial thickening, and central mucus plugging, whereas %NLP correlated significantly with dilated airways, mucus plugging, and dense opacities.