From the Institute of Diagnostic and Interventional Radiology.
Department of Cardiology, University Heart Center, University Hospital Zurich.
Invest Radiol. 2020 Jul;55(7):445-450. doi: 10.1097/RLI.0000000000000655.
Late gadolinium enhancement (LGE) visualizes scar tissue after myocardial infarction. However, in clinically used LGE sequences, subendocardial infarcts can be missed due to low contrast between blood pool and subendocardium. The purpose of his study was to compare scar visibility in a novel 3-dimensional (3D) single breath-hold inversion recovery sequence with fixed, short inversion time (TI = 100 milliseconds) (short LGE) and standard 3D LGE imaging with individually adjusted TI (LGE).
Short LGE and LGE (both sequences with the same settings: spatial resolution, 1.2 × 1.2 mm; slice thickness, 8 mm; field of view, 350 × 350 mm; single breath-hold) were acquired in 64 patients with previous MI (13 female; mean age, 57 ± 19 years) at 1.5 T. Inversion time was set to 100 milliseconds in short LGE and adjusted individually in LGE according to the Look-Locker sequence. Two independent readers evaluated 1088 segments (17-segment model), identified infarcted segments, and categorized scar visibility (5 = excellent, 1 = poor scar visibility) and scar transmurality (4 = transmural, 0 = no scar) using a 5-point Likert scale. Signal intensity ratios between short LGE and LGE for scar and blood pool, for scar and remote myocardium, and for remote myocardium and blood pool were calculated.
Short LGE showed 197 infarcted segments out of 1088 (18.1%); LGE revealed 191 segments (17.6%). Short LGE with dark scar and bright blood pool demonstrated better overall scar visibility, especially in subendocardially infarcted segments compared with LGE (4.2 vs 3.0, 5 = excellent visibility; P = 0.01). Signal intensity ratios for short LGE relative to LGE were 1.42 for scar/blood pool, 0.8 for scar/remote myocardium, and 0.22 for remote myocardium/blood.Overall transmurality was not rated higher in short LGE compared with LGE (P = 0.8). More fibrous tissue and total fibrous percentage (P = 0.04) were measured in short LGE compared with LGE, whereas myocardial mass was not significantly different (P = 0.5). Acquisition time was similar between short LGE and LGE (26 ± 4 seconds vs 25 ± 9 seconds, P = 0.7).
Short LGE is a fast, single breath-hold 3D LGE sequence with no need for myocardial nulling due to fixed inversion time with improved scar visibility, especially in subendocardial infarcts.
晚期钆增强（LGE）可显示心肌梗死后的疤痕组织。然而，在临床使用的 LGE 序列中，由于血池和心内膜下之间的对比度低，可能会错过心内膜下梗死。本研究的目的是比较新型 3 维（3D）单屏气反转恢复序列与固定、短反转时间（TI = 100 毫秒）（短 LGE）和根据个体调整 TI 的标准 3D LGE 成像（LGE）之间的疤痕可见度。
在 1.5T 上对 64 例有既往 MI（13 例女性；平均年龄 57 ± 19 岁）的患者进行短 LGE 和 LGE（两种序列的设置相同：空间分辨率 1.2×1.2mm；层厚 8mm；视野 350×350mm；单屏气）采集。在短 LGE 中，反转时间设置为 100 毫秒，在 LGE 中根据 Look-Locker 序列进行个体调整。两位独立的读者评估了 1088 个节段（17 节段模型），识别梗死节段，并使用 5 分 Likert 量表对疤痕可见性（5=极好，1=疤痕可见性差）和疤痕透壁性（4=透壁，0=无疤痕）进行分类。计算短 LGE 与 LGE 之间的疤痕和血池、疤痕和远隔心肌以及远隔心肌和血池之间的信号强度比。
短 LGE 显示 1088 个节段中的 197 个（18.1%）为梗死节段；LGE 显示 191 个节段（17.6%）。显示黑色疤痕和明亮血池的短 LGE 显示出更好的整体疤痕可见性，尤其是在心内膜下梗死节段与 LGE 相比（4.2 与 3.0，5=极好的可见性；P=0.01）。短 LGE 相对于 LGE 的信号强度比为 1.42 为疤痕/血池，0.8 为疤痕/远隔心肌，0.22 为远隔心肌/血池。与 LGE 相比，短 LGE 的整体透壁性评分并没有更高（P=0.8）。与 LGE 相比，短 LGE 中测量到更多的纤维组织和总纤维百分比（P=0.04），而心肌质量无明显差异（P=0.5）。短 LGE 和 LGE 的采集时间相似（26±4 秒与 25±9 秒，P=0.7）。
短 LGE 是一种快速、单次屏气的 3D LGE 序列，由于固定的反转时间，无需心肌消除，具有改善的疤痕可见性，尤其是在心内膜下梗死中。
