How frequently should we use a phantom for QA? A preliminary assessment

Motivation: Currently, we do not know how frequently quality assurance (QA) should be performed on an MRI scanner to detect changes that impact quantitative measurements. Goal(s): Our goal is to determine the frequency of QA measurements needed during the course of a quantitative in vivo study to have confidence in the in vivo measurements. Approach: Phantom quantitative QA measurements were made immediately before or after the in vivo measurements over the duration of a repeatability study. Results: All quantitative phantom measurements had variation well below 10 % over the course of the 99 day study. Impact: We now know that for measurements using magnetic resonance fingerprinting on this system, QA using phantom measurements is only necessary at the start and end of an in vivo study when the study duration is less than approximately 3 months.