Longitudinal Assessment of Patients With Cystic Fibrosis Lung Disease With Multivolume Noncontrast MRI and Spirometry

Background MRI has been suggested as a radiation-free imaging modality to investigate early structural alterations and regional functional impairment in cystic fibrosis (CF) lung disease. Purpose/Hypothesis To compare functional and morphological MRI changes over the course of the disease to changes in spirometry. Study Type Longitudinal retrospective study. Population Twenty patients with CF lung disease (at baseline, age = 16.5 (13.3-20.6) years, forced expiratory volume in 1 second (as % of predicted [%pred]) FEV1 = 71 (59-87) %pred, forced expiratory flow at 25-75% of forced vital capacity FEF25-75 = 39 (25-63) %pred. Field Strength/Sequence 1.5T / T-2-weighted HASTE; T-2-weighted TSE-PROPELLER; T-2-weighted bSSFP; T-1-weighted 3D GRE. Assessment Nonenhanced chest MRI and spirometry were retrospectively collected over a 3-year period from the initial recruitment visit. Images acquired at end-inspiration and end-expiration were registered by software using the optical flow method to measure expiratory-inspiratory differences in MR signal-intensity (Delta H-1-MRI). Measures of CF functional impairment were defined from Delta H-1-MRI: Delta H-1-MRI median, Delta H-1-MRI quartile coefficient of variation (QCV), and percent low-signal-variation volume (LVV). MR images were also evaluated by three readers using a CF-specific scoring system. Statistical Tests Spearman correlation analysis, Spearman rank correlation analysis, linear mixed-effect model analysis, intraclass correlation coefficient. Results Functional imaging parameters and total morphological score correlated with all spirometric measures, as did subscores of bronchial wall thickening/bronchiectasis, mucus plugging, and consolidation. Overall, the percent change of Delta 1H-MRI median correlated with the percent change of FEV1 (Delta FEV1, r = 0.41, P < 0.01) and the percent change of FEF25-75 (Delta FEF25-75%, r = 0.38, P < 0.01). The percent change of LVV correlated with Delta FEV1 (r = -0.47, P < 0.001) and Delta FEF25-75 (r = -0.50, P < 0.001). Data Conclusion These preliminary results suggest that nonenhanced multivolume MRI may provide a feasible tool to regionally map early pulmonary alterations for longitudinal evaluation of CF lung disease, without exposing the patients to ionizing radiation. Level of Evidence 3T Technical Efficacy Stage 5

Automated summary

This study suggests that nonenhanced multivolume MRI may serve as a feasible tool for regionally mapping early pulmonary alterations in CF lung disease, and is correlated with spirometric measures.