Systolic ShMOLLI myocardial T1-mapping for improved robustness to partial-volume effects and applications in tachyarrhythmias.
Systolic ShMOLLI myocardial T1-mapping for improved robustness to partial-volume effects and applications in tachyarrhythmias.
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DOI：
10.1186/s12968-015-0182-5
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发表时间：
2015-08-28
期刊：
影响因子：
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通讯作者：
Piechnik SK
中科院分区：
文献类型：
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作者：
Ferreira VM;Wijesurendra RS;Liu A;Greiser A;Casadei B;Robson MD;Neubauer S;Piechnik SK
使用缩短的改良Look-Locker反转恢复（ShMOLLI）技术进行t1定位，可以对重要的心肌组织特征进行无创评估。然而，心动过速可能导致误触发和不准确的T1估计。我们开始测试收缩期T1测图是否可以克服这一问题，以及与常规舒张期T1测图相比，T1值或数据质量是否会有显著差异。使用ShMOLLI在1.5 T （Magnetom Avanto, Siemens Healthcare）下获得10名健康志愿者（5名男性）的原生T1图，在不同的规定触发延迟（TD）时间：0,50,100和150 ms（所有“收缩期”），340 ms （MOLLI TD 500 ms， ShMOLLI的传统TD）和“舒张末期”。T1图也使用较短的读数来获取，以探讨减少图像读取时间和对收缩运动的敏感性的影响。对15例速性心律失常患者（房颤13例，窦性心动过速2例，平均HR范围93 ~ 121 bpm）进行了收缩期t1制图的可行性和图像质量测试。在健康志愿者中，与舒张读数相比，收缩读数增加了心肌厚度。TD对T1值的总体影响较小（p = 0.04），收缩期T1值略短于舒张期（最大差10 ms）。虽然存在明显的性别差异（男性的TD对T1值没有影响，女性的差异更明显，女性较薄的心肌节段对T1的影响更大），但轮廓的扩张和侵蚀表明，TD对女性T1的影响几乎完全是由于舒张期更多的部分容积效应。所有T1图的质量都很好，但收缩期TD和较短的读数与节段T1值的变异性较小相关。在心动过速患者中，收缩期征象产生的T1图一致优异（中位R2 = 0.993）。在健康志愿者中，收缩期ShMOLLI T1映射降低了T1变异性，并报告了与常规舒张读数相当的临床T1值；收缩期T1值略短，主要是由于功能性心肌厚度增加导致部分容积效应减少。对于心律失常患者，收缩期ShMOLLI T1测图是可行的，可以避免误触发并产生高质量的T1图。这扩大了其临床适用性，以挑战性的节奏（如快速心房颤动），并有助于研究较薄的心肌段。随着进一步的验证，收缩期t1制图可能成为心肌t1制图新的便捷标准。
T1-mapping using the Shortened Modified Look-Locker Inversion Recovery (ShMOLLI) technique enables non-invasive assessment of important myocardial tissue characteristics. However, tachyarrhythmia may cause mistriggering and inaccurate T1 estimation. We set out to test whether systolic T1-mapping might overcome this, and whether T1 values or data quality would be significantly different compared to conventional diastolic T1-mapping. Native T1 maps were acquired using ShMOLLI at 1.5 T (Magnetom Avanto, Siemens Healthcare) in 10 healthy volunteers (5 male) in sinus rhythm, at varying prescribed trigger delay (TD) times: 0, 50, 100 and 150 ms (all “systolic”), 340 ms (MOLLI TD 500 ms, the conventional TD for ShMOLLI) and also “end diastolic”. T1 maps were also acquired using a shorter readout, to explore the effect of reducing image readout time and sensitivity to systolic motion. The feasibility and image quality of systolic T1-mapping was tested in 15 patients with tachyarrhythmia (n = 13 atrial fibrillation, n = 2 sinus tachycardia; mean HR range 93–121 bpm). In healthy volunteers, systolic readout increased the thickness of myocardium compared to the diastolic readout. There was a small overall effect of TD on T1 values (p = 0.04), with slightly shorter T1 values in systole compared to diastole (maximum difference 10 ms). While there were apparent gender differences (with no effect of TD on T1 values in males, more marked differences in females, and exaggeration of this effect in thinner myocardial segments in females), dilatation and erosion of contours suggested that the effect of TD on T1 in females was almost entirely due to more partial-volume effects in diastole. All T1 maps were of excellent quality, but systolic TD and shorter readout were associated with less variability in segmental T1 values. In tachycardic patients, systolic acquisitions produced consistently excellent T1 maps (median R2 = 0.993). In healthy volunteers, systolic ShMOLLI T1-mapping reduces T1 variability and reports clinically equivalent T1 values to conventional diastolic readout; slightly shorter T1 values in systole are mostly explained by reduced partial-volume effects due to the increase in functional myocardial thickness. In patients with tachyarrhythmia, systolic ShMOLLI T1-mapping is feasible, circumvents mistriggering and produces excellent quality T1 maps. This extends its clinical applicability to challenging rhythms (such as rapid atrial fibrillation) and aids the investigation of thinner myocardial segments. With further validation, systolic T1-mapping may become a new and convenient standard for myocardial T1-mapping.