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

Abstract

PURPOSE: To validate the feasibility of quantitative Tmapping as a novel, gadolinium-free, preclinical biomarker of interstitial lung disease (ILD). METHODS: Quantitative Tmapping 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 Trelaxation 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 Trelaxation in healthy mice showed a mean value of 10.51 ± 0.56 ms. During ILD development, the mean Tincreased 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: Tmapping of mouse lungs can be successfully applied at 9.4 T, offering quantitative insights through parametric Tmapping across various ILD models without requiring contrast agents. The proposed method for evaluating lung tissue damage is adaptable to other interstitial lung diseases.