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Abstract

Introduction: Advances in low-field MRI (B0<0.1T) empower the use of portable point-of-care (POC) systems as additional information source for the clinical routine and low-income countries 1,2. Despite SNR limits and associated longer scan times, benefits like low-cost, smaller footprint, and safety promote new methods to increase the diagnostic value of low-field MRI worldwide 3. Quantitative MRI potentially improves clinical certainty, but precise parameter estimation at low-field is hampered by long scan times 4. The balanced steady-state free precession (bSSFP) sequence provides the highest SNR per unit time and mixed T2/T1 sensitivity5, offering rapid multi-parametric relaxometry6 . We investigate a frequency offset-cycled bSSFP sequence using our 46 mT POC MRI scanner for simultaneous T1 and T2 mapping in vitro. We further propose a procedure to mitigate and correct for B 0 drift on a Halbach low-field scanner.