The following is a summary of “Dynamic contrast enhanced MRI for the evaluation of lung perfusion in idiopathic pulmonary fibrosis” published in the October 2022 issue of Respiratory by Torres et al.

The goal of this study was to use quantitative and semiquantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) methods to measure lung perfusion in idiopathic pulmonary fibrosis (IPF). At the start of this prospective trial, DCE-MRI was used to study 41 people, both healthy controls and people with IPF. IPF subjects were then followed for 1 year; progressive IPF (IPFprog) subjects were distinguished from stable IPF (IPFstable) subjects based on a decline in percent predicted forced vital capacity (FVC % pred) or diffusing capacity of the lung for carbon monoxide (DLCO % pred) measured during follow-up visits. About  35 of the 41 people were kept for the final baseline analysis (n=15 in the control group, n=14 in the IPFstable group, and n=6 in the IPFprog group). With temporally resolved DCE-MRI, 7 measures and their coefficients of variation (CV) were found.

Using linear regression analysis, 2 sets of global and regional comparisons were made: control groups vs. IPF groups and control groups vs. IPFstable vs. IPFprog groups. Spearman rank correlation was used to compare each measure with FVC% pred, DLCO% pred, and the lung clearance index (LCI% pred). Using first-moment transit time (FMTT), contrast uptake slope, and pulmonary blood flow (PBF) (P≤0.05), DCE-MRI found differences in regional perfusion between people without IPF and people with IPF. Global averages did not find these differences. IPFprog had a shorter FMTT than both IPFstable (P=0.004) and the control group (P=0.023). There were correlations between PBF CV and both DLCO% predicted (rs=−0.48, P=0.022) and LCI% predicted (rs=+0.47, P=0.015).

Age (P<0.001), DLCO% pred (P<0.001), FVC% pred (P=0.001), and LCI% pred (P=0.007) were all found to be different between the groups. When DCE-MRI is used in IPF, global analysis hides regional changes in pulmonary hemodynamics. A decrease in FMTT could be a sign that IPF is getting worse.