评估扫描仪升级对临床研究的影响。
Assessing effects of scanner upgrades for clinical studies.
机构信息
Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA.
Information Technology Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA.
出版信息
J Magn Reson Imaging. 2019 Dec;50(6):1948-1954. doi: 10.1002/jmri.26785. Epub 2019 May 21.
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 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 IR, VFA at 3T.
ASSESSMENT
The T 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 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 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 IR errors decreased to ±10% post-upgrade.
DATA CONCLUSION
The T VFA measurement differences between the original and post-upgrade systems can be entirely attributed to contributions from B . The T 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 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.
背景
由于软件和硬件的变化，扫描仪的升级是磁共振研究中不可避免的一部分，如果没有质量保证协议，可能会危及研究。
目的
评估在经历了“除磁体外的一切”升级的 3T 系统上，通过反转恢复（IR）和可变翻转角（VFA）测量得出 T 弛豫时间的变化。
研究类型
纵向。
体模
国际磁共振医学学会/美国国家标准与技术研究院（ISMRM/NIST）系统体模，在多个（n=3）天内进行重复测量。
磁场强度/序列：T IR、VFA 在 3T。
评估
通过 IR 和 VFA 进行的 T 测量与构成 ISMRM/NIST 系统体模已知值的核磁共振（NMR）测量进行比较，以确定测量误差。
统计检验
描述性。
结果
在原始系统上，T VFA 测量误差分布在零周围（-15%至+10%），然后误差分布完全在升级后为正（+5%至 30%）。在确定信号饱和为问题之前，T IR 结果的误差分布急剧增加（原始系统为±5%，升级后为±20%）。一旦考虑到信号饱和，T IR 误差在升级后降至±10%。
数据结论
原始系统和升级系统之间 T VFA 测量差异可完全归因于 B 的贡献。T IR 测量表明需要进行定量质量保证（QA）过程。研究中涉及的站点通过了现行的 QA 协议，但没有发现 T 误差增加，也没有发现信号饱和问题。为了改进本研究，我们将在硬件或软件升级后，每隔不到一年的时间进行系统的、定量的测量。
证据水平
1 技术功效：阶段 2 J.磁共振成像 2019。J.磁共振成像 2019；50：1948-1954.
Zotero 插件