Non-invasive Free-breathing Gating-free Extracellular Cellular Volume Quantification for Repetitive Myocardial Fibrosis Evaluation in Rodents.

Background: Interstitial myocardial fibrosis is a crucial pathological feature of many cardiovascular disorders. Myocardial fibrosis resulting in extracellular volume (ECV) expansion can be non-invasively quantified by cardiac MRI (CMR) with T Methods: To address these challenges, the objective of this study is to establish a fast, free-breathing, and gating-free ECV procedure with a non-invasive subcutaneous catheter for in-scanner Gd administration that can allow longitudinal repetitive ECV evaluations in rodent models. This is achieved by (1) IntraGate sequence for free-breathing gating-free cardiac imaging, (2) non-invasive subcutaneous in-scanner Gd administration, and (3) fast T Results: We have successfully established a non-invasive fast ECV quantification protocol to enable longitudinal repetitive ECV quantifications in rodents. Non-invasive subcutaneous Gd bolus administration induced reasonable dynamic contrast enhancement (DCE) time course reaching a steady state in ~ 20 min for stable T Conclusion: We have established a simple, fast, non-invasive, and robust CMR protocol in rodents that can enable longitudinal repetitive ECV quantifications for cardiovascular disease progression. It can be used to monitor disease regression with interventions.