Dynamic contrast enhanced MRI for the evaluation of lung perfusion in idiopathic pulmonary fibrosis.

BACKGROUND

The objective of this work was to apply quantitative and semiquantitative dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) methods to evaluate lung perfusion in idiopathic pulmonary fibrosis (IPF).

METHODS

In this prospective trial 41 subjects, including healthy control and IPF subjects, were studied using DCE-MRI at baseline. IPF subjects were then followed for 1 year; progressive IPF (IPF) subjects were distinguished from stable IPF (IPF) subjects based on a decline in percent predicted forced vital capacity (FVC % pred) or diffusing capacity of the lung for carbon monoxide ( % pred) measured during follow-up visits. 35 out of 41 subjects were retained for final baseline analysis (control: n=15; IPF: n=14; IPF: n=6). 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 IPF groups and control IPF IPF groups, using linear regression analysis. Each measure was compared with FVC % pred, % 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. FMTT was shorter for IPF compared with both IPF (p=0.004) and control groups (p=0.023). Correlations were observed between PBF CV and % pred (r= -0.48, p=0.022) and LCI % pred (r= +0.47, p=0.015). Significant group differences were detected in age (p<0.001), % pred (p<0.001), FVC % pred (p=0.001) and LCI % pred (p=0.007).

CONCLUSIONS

Global analysis obscures regional changes in pulmonary haemodynamics in IPF using DCE-MRI in IPF. Decreased FMTT may be a candidate marker for IPF progression.