Quantitative T₂ mapping of lung parenchyma at 9.4 T: A feasibility study in three murine models of interstitial lung...

To validate the feasibility of quantitative T₂ mapping as a novel, gadolinium-free, preclinical biomarker of interstitial lung disease (ILD).

Quantitative T₂ mapping of lung parenchyma was obtained with multiple-slice multiple-echo readout. A mono-exponential model of magnetization decay was fit to the data to obtain parametric maps of T₂ relaxation time in four slices across whole lungs. The measurements were performed in three clinically relevant murine models ILD: acute lung injury due to endotoxemia, chronic recovery phase post-influenza infection, and bleomycin-induced interstitial lung fibrosis.

Quantitative maps of T₂ relaxation in healthy mice showed a mean value of 10.51 ± 0.56 ms. During ILD development, the mean T₂ increased up to threefold, showing high sensitivity to altered tissue water content due to augmented fraction of macromolecules in fibrosis or inflammation associated with disease progression.

T₂ mapping of mouse lungs can be successfully applied at 9.4 T, offering quantitative insights through parametric T₂ mapping across various ILD models without requiring contrast agents. The proposed method for evaluating lung tissue damage is adaptable to other interstitial lung diseases.