Pulmonary MRI contrast using Surface Quadrupolar Relaxation (SQUARE) of hyperpolarized83 Kr

Abstract Hyperpolarized83 Kr has previously been demonstrated to enable MRI contrast that is sensitive to the chemical composition of the surface in a porous model system. Methodological advances have lead to a substantial increase in the83 Kr hyperpolarization and the resulting signal intensity. Using the improved methodology for spin exchange optical pumping of isotopically enriched83 Kr, internal anatomical details of ex vivo rodent lung were resolved with hyperpolarized83 Kr MRI after krypton inhalation. Different83 Kr relaxation times were found between the main bronchi and the parenchymal regions in ex vivo rat lungs. The T1 weighted hyperpolarized83 Kr MRI provided a first demonstration of surface quadrupolar relaxation (SQUARE) pulmonary MRI contrast.