Dabir Darius, Child Nicholas, Kalra Ashwin, Rogers Toby, Gebker Rolf, Jabbour Andrew, Plein Sven, Yu Chung-Yao, Otton James, Kidambi Ananth, McDiarmid Adam, Broadbent David, Higgins David M, Schnackenburg Bernhard, Foote Lucy, Cummins Ciara, Nagel Eike, Puntmann Valentina O
J Cardiovasc Magn Reson. 2014 Oct 21;16(1):69. doi: 10.1186/s12968-014-0069-x.
T1 mapping is a robust and highly reproducible application to quantify myocardial relaxation of longitudinal magnetisation. Available T1 mapping methods are presently site and vendor specific, with variable accuracy and precision of T1 values between the systems and sequences. We assessed the transferability of a T1 mapping method and determined the reference values of healthy human myocardium in a multicenter setting.
Healthy subjects (n=102; mean age 41 years (range 17-83), male, n=53 (52%)), with no previous medical history, and normotensive low risk subjects (n=113) referred for clinical cardiovascular magnetic resonance (CMR) were examined. Further inclusion criteria for all were absence of regular medication and subsequently normal findings of routine CMR. All subjects underwent T1 mapping using a uniform imaging set-up (modified Look- Locker inversion recovery, MOLLI, using scheme 3(3)3(3)5)) on 1.5 Tesla (T) and 3 T Philips scanners. Native T1-maps were acquired in a single midventricular short axis slice and repeated 20 minutes following gadobutrol. Reference values were obtained for native T1 and gadolinium-based partition coefficients, λ and extracellular volume fraction (ECV) in a core lab using standardized postprocessing.
In healthy controls, mean native T1 values were 950±21 msec at 1.5 T and 1052±23 at 3 T. λ and ECV values were 0.44±0.06 and 0.25±0.04 at 1.5 T, and 0.44±0.07 and 0.26±0.04 at 3 T, respectively. There were no significant differences between healthy controls and low risk subjects in routine CMR parameters and T1 values. The entire cohort showed no correlation between age, gender and native T1. Cross-center comparisons of mean values showed no significant difference for any of the T1 indices at any field strength. There were considerable regional differences in segmental T1 values. λ and ECV were found to be dose dependent. There was excellent inter- and intraobserver reproducibility for measurement of native septal T1.
We show transferability for a unifying T1 mapping methodology in a multicenter setting. We provide reference ranges for T1 values in healthy human myocardium, which can be applied across participating sites.
T1 映射是一种强大且高度可重复的应用，用于量化心肌纵向磁化的弛豫。目前可用的 T1 映射方法因设备和供应商而异，不同系统和序列之间 T1 值的准确性和精密度各不相同。我们评估了一种 T1 映射方法的可转移性，并在多中心环境中确定了健康人心肌的参考值。
对健康受试者（n = 102；平均年龄 41 岁（范围 17 - 83 岁），男性，n = 53（52%））进行检查，这些受试者无既往病史，以及因临床心血管磁共振（CMR）检查而转诊的血压正常的低风险受试者（n = 113）。所有受试者的进一步纳入标准为未规律用药且随后常规 CMR 检查结果正常。所有受试者在 1.5 特斯拉（T）和 3T 的飞利浦扫描仪上使用统一的成像设置（改良 Look - Locker 反转恢复序列，MOLLI，采用 3(3)3(3)5 方案）进行 T1 映射。在单个心室中部短轴切片中获取原始 T1 图，并在注射钆布醇后 20 分钟重复采集。在核心实验室使用标准化后处理获得原始 T1、基于钆的分配系数λ和细胞外体积分数（ECV）的参考值。
在健康对照组中，1.5T 时平均原始 T1 值为 950±21 毫秒，3T 时为 1052±23 毫秒。1.5T 时λ和 ECV 值分别为 0.44±0.06 和 0.25±0.04，3T 时分别为 0.44±0.07 和 0.26±0.04。健康对照组和低风险受试者在常规 CMR 参数和 T1 值方面无显著差异。整个队列中年龄、性别与原始 T1 之间无相关性。平均值的跨中心比较显示在任何场强下任何 T1 指标均无显著差异。节段性 T1 值存在相当大的区域差异。发现λ和 ECV 与剂量相关。原始间隔 T1 测量的观察者间和观察者内再现性都非常好。
我们展示了一种统一的 T1 映射方法在多中心环境中的可转移性。我们提供了健康人心肌 T1 值的参考范围，可应用于各参与站点。
