Quantifying Rotational Correlation Time in Clinical MRI Scanners: A Novel Framework for Enhanced Tissue Characterization

Motivation: This study exploits the underexplored potential of paramagnetic relaxation enhancement (PRE) in clinical MR scanners to characterize molecular interactions and tissue microenvironments in vivo, leveraging Gadolinium-based contrast agents (GBCAs). Goal(s): Develop and validate methodology for estimating Gadolinium-based contrast agent (GBCA) correlation time via relaxivity ratio measurements at 1.5 and 3 Tesla. Approach: Applying relaxation models, we devised a dictionary-matching framework correlating GBCA relaxivities with correlation times, and validated our methods using phantom experiments. Results: Our framework accurately estimates GBCA correlation times at a single field strength showing <5% error (1.5T to 3T) and <11% (3T to 1.5T) in cross-field relaxivity predictions. Impact: This framework leverages MR Relaxometry for precise estimation of GBCA rotational correlation time at single field strengths, offering insights in tissue characteristics. There is significant potential to improve tumor imaging and diagnosis through insights into pH, viscosity, and protein interactions .