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Background Scanner upgrades due to software and hardware changes are an inevitable part of MR research and, without quality assurance protocols, can jeopardize studies. Purpose To evaluate changes in T 1 relaxation time by inversion recovery (IR) and variable flip angle (VFA) measurements on a 3T system that underwent an "everything but the magnet" upgrade. Study Type Longitudinal. Phantom An International Society of Magnetic Resonance in Medicine / National Institute of Standards and Technology (ISMRM/NIST) system phantom with repeated measurements across multiple ( n = 3) days. Field Strength/Sequence T 1 IR, VFA at 3T. Assessment The T 1 measurements by IR and VFA were compared with the nuclear magnetic resonance (NMR) measurements, which constitute the known values for the ISMRM/NIST system phantom, to determine the measurement error. Statistical Tests Descriptive. Results The T 1 VFA measurement errors were distributed around zero (–15% to +10%) on the original system and then the errors were distributed entirely above zero post‐upgrade (+5% to 30%). The T 1 IR results had a dramatic increase in error distribution (±5% original, ±20% post‐upgrade) prior to the identification of signal saturation as an issue. Once the signal saturation was accounted for, the T 1 IR errors decreased to ±10% post‐upgrade. Data Conclusion The T 1 VFA measurement differences between the original and post‐upgrade systems can be entirely attributed to contributions from B 1 . The T 1 IR measurements demonstrate the need for quantitative quality assurance (QA) processes. The site under study passed the QA protocols in place, which did not identify the increased T 1 error, nor the signal saturation issue. To improve on this study, we would make systematic, quantitative measurements at intervals less than a year and following any hardware or software upgrade. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2019;50:1948–1954.
Keenan et al. (Tue,) studied this question.