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

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

METHODS

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.

RESULTS

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.

CONCLUSION

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.