A relaxometry method that emphasizes practicality and availability.
A relaxometry method that emphasizes practicality and availability.
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强调实用性和可用性的松弛测量方法。
DOI：
10.1002/mrm.29394
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发表时间：
2022
影响因子：
3.3
通讯作者：
Mihai,Georgeta
中科院分区：
文献类型：
--
作者：
Madore,Bruno;Jerosch-Herold,Michael;Chiou,Jr-YuanGeorge;Cheng,Cheng-Chieh;Guenette,JeffreyP;Mihai,Georgeta
虽然已经提出了许多方法来定量标测MRI的主要参数(如T1、T2、C×M0)，但这些方法通常涉及临床扫描仪上不易获得的特殊序列和/或可能需要较长的扫描时间。与之相比，提出的方法可以在大多数扫描仪上运行，在扫描时间和图像质量之间提供灵活的折衷，并联合映射MRI参数以确保空间对齐。推导了相应的信号方程，并提出了相应的求解策略。与通常的多镜头EPI一样，通过调整回声序列长度，扫描时间可以很容易地与图像质量进行权衡。在含有不同浓度的加多布曲尔和加多特罗葡甲胺造影剂的凝胶模体中，对照参考松弛计量法进行验证。结果经Bland-Altman分析：与2D SE相比，T2的偏差为0.29 ms，95%的符合范围为−1.15~+1.73 ms。对于T1，与反转-恢复SE(和Molli)相比，偏差为−20.2ms(和−14.5ms)，协议限制范围为−62.4ms到+22.0ms(和−53.8ms到+24.9ms)。两种参考方法的平均相对T1误差与参考方法相近。结论在现有的松弛测量方法中，该方法具有较好的实用性和可用性。
PurposeAlthough many methods have been proposed to quantitatively map the main MRI parameters (e.g., T1, T2,C×M0), these methods often involve special sequences not readily available on clinical scanners and/or may require long scan times. In contrast, the proposed method can readily run on most scanners, offer flexible tradeoffs between scan time and image quality, and map MRI parameters jointly to ensure spatial alignment.MethodsThe approach is based on the multi‐shot spin‐echo (SE) EPI sequence. The corresponding signal equation was derived and strategies for solving it were developed. As usual with multi‐shot EPI, scan time can readily be traded‐off against image quality by adjusting the echo train length. Validation was performed against reference relaxometry methods, in gel phantoms with varying concentrations of gadobutrol and gadoterate meglumine contrast agents. In vivo examples are further presented, from 3 neuroradiology patients.ResultsBland–Altman analysis was performed: for T2, as compared to 2D SE, bias was 0.29 ms and the 95% limits of agreement ranged from −1.15 to +1.73 ms. For T1, compared to inversion‐recovery SE (and MOLLI), bias was −20.2 ms (and −14.5 ms) and the limits of agreement ranged from −62.4 to +22.0 ms (and −53.8 to +24.9 ms). The mean relative T1error between the proposed method and each of the 2 reference methods was similar to that of the reference methods among themselves.ConclusionIn the constellation of existing relaxometry methods, the proposed method is meant to stand out in terms of its practicality and availability.