Dynamic contrast enhanced MRI may reveal hemodynamic changes in idiopathic pulmonary fibrosis.

A new study revealed that dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) can identify regional changes in pulmonary hemodynamics in Idiopathic pulmonary fibrosis obscured by global analysis. The study results were published in the European Respiratory Journal. 

Idiopathic pulmonary fibrosis (IPF) is the most common idiopathic interstitial lung disease. Dynamic contrast-enhanced MRI (DCE-MRI) is used for the functional perfusion assessment mainly for the myocardium, brain and other oncological targets. Recently researchers conducted a prospective trial to apply quantitative and semiquantitative DCE-MRI methods to evaluate lung perfusion in idiopathic pulmonary fibrosis (IPF). 

Using DCE-MRI at baseline 41 subjects including healthy control and IPF subjects, were assessed and the IPF subjects were then followed for 1 year. Among IPF patients 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. For final baseline analysis 35 out of 41 subjects were retained. There were 15 controls; 14 subjects in IPFstable; and 6 in IPFprog. Seven measures and their coefficients of variation (CV) were derived using temporally resolved DCE-MRI. Two sets of global and regional comparisons were made: control versus IPF groups and control versus IPFstable versus IPFprog groups, using linear regression analysis. Each measure was compared with FVC % pred, DLCO % pred and the lung clearance index (LCI % pred) using a Spearman rank correlation. 

Results: 

DCE-MRI identified regional perfusion differences between control and IPF subjects using first moment transit time (FMTT), contrast uptake slope and pulmonary blood flow (PBF) (p≤0.05), while global averages did not.

IPFprog had shorter FMTT compared with both IPFstable (p=0.004) and control groups (p=0.023).

Correlations were observed between PBF CV and DLCO % pred (rs= −0.48, p=0.022) and LCI % pred (rs= +0.47, p=0.015).

Significant group differences were detected in age (p<0.001), DLCO % pred (p<0.001), FVC % pred (p=0.001) and LCI % pred (p=0.007). 

Thus, DCE-MRI predicts regional changes in pulmonary haemodynamics in IPF that were concealed by Global analysis. Decreased FMTT may be a candidate marker for IPF progression.