Oxford Centre for Clinical Magnetic Resonance Research, Oxford BRC NIHR, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, UK.
Oxford Centre for Clinical Magnetic Resonance Research, Oxford BRC NIHR, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, UK.
Int J Cardiol. 2021 May 1;330:251-258. doi: 10.1016/j.ijcard.2021.01.026. Epub 2021 Jan 31.
Quantitative cardiovascular magnetic resonance T1-mapping is increasingly used for myocardial tissue characterization. However, the lack of standardization limits direct comparability between centers and wider roll-out for clinical use or trials.
To develop a quality assurance (QA) program assuring standardized T1 measurements for clinical use.
MR phantoms manufactured in 2013 were distributed, including ShMOLLI T1-mapping and reference T1 and T2 protocols. We first studied the T1 and T2 dependency on temperature and phantom aging using phantom datasets from a single site over 4 years. Based on this, we developed a multiparametric QA model, which was then applied to 78 scans from 28 other multi-national sites.
T1 temperature sensitivity followed a second-order polynomial to baseline T1 values (R > 0.996). Some phantoms showed aging effects, where T1 drifted up to 49% over 40 months. The correlation model based on reference T1 and T2, developed on 1004 dedicated phantom scans, predicted ShMOLLI-T1 with high consistency (coefficient of variation 1.54%), and was robust to temperature variations and phantom aging. Using the 95% confidence interval of the correlation model residuals as the tolerance range, we analyzed 390 ShMOLLI T1-maps and confirmed accurate sequence deployment in 90%(70/78) of QA scans across 28 multiple centers, and categorized the rest with specific remedial actions.
The proposed phantom QA for T1-mapping can assure correct method implementation and protocol adherence, and is robust to temperature variation and phantom aging. This QA program circumvents the need of frequent phantom replacements, and can be readily deployed in multicenter trials.
定量心血管磁共振 T1 映射技术越来越多地用于心肌组织特征分析。然而，由于缺乏标准化，限制了各中心之间的直接可比性，也限制了其在临床应用或试验中的广泛推广。
制定质量保证（QA）计划，确保 T1 测量标准化，以用于临床。
2013 年制造的磁共振（MR）体模，包括 ShMOLLI T1 映射和参考 T1 和 T2 协议，分发给各个中心。我们首先使用单个中心的体模数据集，在 4 年内研究 T1 和 T2 对温度和体模老化的依赖性。在此基础上，我们开发了一个多参数 QA 模型，然后将其应用于 28 个多国家中心的 78 个扫描。
T1 对温度的敏感性遵循与基线 T1 值的二次多项式关系（R>0.996）。一些体模显示出老化效应，其中 T1 在 40 个月内漂移了高达 49%。基于 1004 次专用体模扫描建立的基于参考 T1 和 T2 的相关模型，对 ShMOLLI-T1 具有很高的一致性（变异系数为 1.54%），并且对温度变化和体模老化具有鲁棒性。使用相关模型残差的 95%置信区间作为容差范围，我们分析了 390 次 ShMOLLI T1 映射，并确认在 28 个多中心的 78 次 QA 扫描中，有 90%（70/78）的序列正确部署，并对其余的扫描进行了分类，给出了具体的补救措施。
本研究提出的 T1 映射体模 QA 可确保正确的方法实施和协议遵循，并且对温度变化和体模老化具有鲁棒性。该 QA 计划避免了频繁更换体模的需要，并且可以在多中心试验中得到很好的应用。
