Ventilation and perfusion assessed by functional MRI in children with CF: reproducibility in comparison to lung function

Background: Chronic lung diseases such as cystic fibrosis (CF) can be monitored by imaging and lung function modalities. Magnetic resonance imaging (MRI) techniques such as matrix pencil (MP) decomposition allows for evaluation of regional impairment of fractional ventilation (R-FV) and relative perfusion (R-Q). However, reproducibility of MP MRI outcomes in children with CF is unknown. We examined short-term variability of ventilation and perfusion impairment from MP MRI and compared this to lung function outcomes. Method: Twenty-threeCF and 12 healthy school-aged children underwent MRI and lung function tests on the same day on two occasions 24 h apart. Global ventilation inhomogeneity was assessed by the lung clearance index (LCI) from nitrogen-multiple breath washout (N-2-MBW) technique. Intra-class-coefficient (ICC), percentage change, and Bland-Altman limits of agreement were evaluated to assess reproducibility. Results: Sixty-nine measurements from MP MRI and N-2-MBW were performed. The ICC between two visits for R-FV, R-Q and LCI ranged between 0.60 and 0.90 in individuals with CF and healthy controls. In individuals with CF, percentage of change between the visits was 0.02% for R-FV, -1.11% for R-Q and 2.91% for LCI and limits of agreement between visits were - 4.3% and 3.9% for R-FV, -4.4% and 3.7% for R-Q, and -2.6 and 3.0 for LCI. Conclusions: Functional imaging is reproducible and short-term changes in RFV and RQ greater than +/- 4.4% can be considered clinical meaningful. Very good short-term reproducibility, and easy application without the need for breathing maneuvers or contrast agent, makes MP MRI a promising surveillance method for CF. (C) 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.