Quantitative multivolume magnetic resonance imaging (1H-MRI) in patients with cystic fibrosis (CF) lung disease:comparison with FEV1 and lung clearance index (LCI)

Abstract

Regional intensity variations between 1H-MRI scans acquired at different lung volumes (Δ1H-MRI) can estimate regional ventilation (Pennati, Radiology2014). The study aims to evaluate if Δ1H-MRI correlates with FEV1 %pred and LCI in patients with CF lung disease. 28 patients with CF lung disease (10-27 years, FEV1=78.3±24.4 %pred, LCI=14.9±3.7) performed chest MRI, spirometry and multiple breath washout. Images acquired at end-inspiration (INSP) and end-expiration (EXP) were registered by optical flow to obtain Δ1H-MRI maps as a measure of regional ventilation. We defined the percent of low ventilation volume (%LVV) as the percent of lung volume with Δ1H-MRI less than 5% of the mean heart signal. Maps of Δ1H-MRI (Fig. 1A) and corresponding maps of %LVV (Fig.1B) are shown in two representative patients. In the overall population, %LVV ranged from 4.7% to 28% of total lung volume. %LVV negatively correlated with FEV1 %pred (r2=0.36, p=0.0007) and positively correlated with LCI (r2=0.66, p In conclusion, quantitative multivolume MRI correlated with FEV1 %pred and LCI, with a strong relationship with ventilation heterogeneity. Thus, MRI, as a non-ionizing imaging technique, is particularly attractive in CF care for longitudinal evaluation, providing a unique tool to regionally map early pulmonary alterations.