BACKGROUND T1 mapping sequences such as MOLLI, ShMOLLI and SASHA make use of different technical approaches, bearing strengths and weaknesses. It is well known that obtained T1 relaxation times differ between the sequence techniques as well as between different hardware. Yet, T1 quantification is a promising tool for myocardial tissue characterization, disregarding the absence of established reference values. The purpose of this study was to evaluate the feasibility of native and post-contrast T1 mapping methods as well as ECV maps and its diagnostic benefits in a clinical environment when scanning patients with various cardiac diseases at 3 T. METHODS Native and post-contrast T1 mapping data acquired on a 3 T full-body scanner using the three pulse sequences 5(3)3 MOLLI, ShMOLLI and SASHA in 19 patients with clinical indication for contrast enhanced MRI were compared. We analyzed global and segmental T1 relaxation times as well as respective extracellular volumes and compared the emerged differences between the used pulse sequences. RESULTS T1 times acquired with MOLLI and ShMOLLI exhibited systematic T1 deviation compared to SASHA. Myocardial MOLLI T1 times were 19% lower and ShMOLLI T1 times 25% lower compared to SASHA. Native blood T1 times from MOLLI were 13% lower than SASHA, while post-contrast MOLLI T1-times were only 5% lower. ECV values exhibited comparably biased estimation with MOLLI and ShMOLLI compared to SASHA in good agreement with results reported in literature. Pathology-suspect segments were clearly differentiated from remote myocardium with all three sequences. CONCLUSION Myocardial T1 mapping yields systematically biased pre- and post-contrast T1 times depending on the applied pulse sequence. Additionally calculating ECV attenuates this bias, making MOLLI, ShMOLLI and SASHA better comparable. Therefore, myocardial T1 mapping is a powerful clinical tool for classification of soft tissue abnormalities in spite of the absence of established reference values.

中文翻译：

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T1和ECV映射在3 T时的临床常规中：MOLLI，ShMOLLI和SASHA之间的差异。

背景技术T1映射序列（例如MOLLI，ShMOLLI和SASHA）利用不同的技术方法，优势和劣势。众所周知，获得的T1弛豫时间在序列技术之间以及在不同的硬件之间都不同。然而，T1定量是用于心肌组织表征的有前途的工具，而忽略了既定参考值的缺乏。这项研究的目的是评估在3 T扫描患有各种心脏病的患者时，天然T1和造影剂T1定位方法以及ECV图的可行性及其在临床环境中的诊断价值。方法T1天然和T1造影剂使用3个脉冲序列5（3）3 MOLLI在3 T全身扫描仪上获取的映射数据，比较了19例具有MRI增强对比的临床指征的ShMOLLI和SASHA。我们分析了整体和节段的T1弛豫时间以及各自的细胞外体积，并比较了所用脉冲序列之间出现的差异。结果与SASHA相比，用MOLLI和ShMOLLI采集的T1时间表现出系统的T1偏差。与SASHA相比，心肌MOLLI T1降低19％，ShMOLLI T1降低25％。来自MOLLI的天然血液T1次比SASHA低13％，而对比后MOLLI T1次仅降低5％。与SASHA相比，MOLLI和ShMOLLI的ECV值显示出相对偏差的估计，与文献报道的结果吻合良好。在所有三个序列中，病理可疑段均与远端心肌区分开来。结论心肌T1映射会根据所施加的脉冲序列，产生对比前和对比后T1时间的系统偏差。另外，计算ECV可以减弱此偏差，从而使MOLLI，ShMOLLI和SASHA具有更好的可比性。因此，尽管没有确定的参考值，心肌T1作图是对软组织异常进行分类的有力临床工具。