COPD Patients Have Short Lung Magnetic Resonance T1 Relaxation Time

Magnetic resonance imaging (MRI) may provide attractive biomarkers for assessment of pulmonary disease in clinical trials as it is free from ionizing radiation, minimally invasive and allows regional information. The aim of this study was to characterize lung MRI T-1 relaxation time as a biomarker of chronic obstructive pulmonary disease (COPD); and specifically its relationship to smoking history, computed tomography (CT), and pulmonary function test (PFT) measurements in comparison to healthy age-matched controls. Lung T-1 and inter-quartile range (IQR) of T-1 maps from 24 COPD subjects and 12 healthy age-matched non-smokers were retrospectively analyzed from an institutional review board approved study. The subjects underwent PFTs and two separate MR imaging sessions at 1.5 tesla to test T-1 repeatability. CT scans were performed on the COPD subjects. T-1 repeatability (intraclass correlation coefficient) was 0.72 for repeated scans acquired on two visits. The lung T-1 was significantly shorter (p < 0.0001) and T-1 IQR was significantly larger (p = 0.0002) for the COPD subjects compared to healthy controls. Lung T-1 significantly (p = 0.001) correlated with lung density assessed with CT. Strong significant correlations (p < 0.0001) between lung T-1 and all PFT measurements were observed. Cigarette exposure did not correlate with lung T-1 in COPD subjects. In conclusion, lung MRI T-1 mapping shows potential as a repeatable, radiation free, non-invasive imaging technique in the evaluation of COPD.