UCL Centre for Advanced Biomedical Imaging, Department of Medicine and UCL Institute of Child Health, University College London, Medical School, and The Hatter Cardiovascular Institute, University College London Hospital, UK.
J Cardiovasc Magn Reson. 2011 Sep 5;13(1):44. doi: 10.1186/1532-429X-13-44.
Myocardial infarction (MI) can be readily assessed using late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR). Inversion recovery (IR) sequences provide the highest contrast between enhanced infarct areas and healthy myocardium. Applying such methods to small animals is challenging due to rapid respiratory and cardiac rates relative to T1 relaxation.
Here we present a fast and robust protocol for assessing LGE in small animals using a multi-slice IR gradient echo sequence for efficient assessment of LGE. An additional Look-Locker sequence was used to assess the optimum inversion point on an individual basis and to determine most appropriate gating points for both rat and mouse. The technique was applied to two preclinical scenarios: i) an acute (2 hour) reperfused model of MI in rats and ii) mice 2 days following non-reperfused MI.
LGE images from all animals revealed clear areas of enhancement allowing for easy volume segmentation. Typical inversion times required to null healthy myocardium in rats were between 300-450 ms equivalent to 2-3 R-waves and ~330 ms in mice, typically 3 R-waves following inversion. Data from rats was also validated against triphenyltetrazolium chloride staining and revealed close agreement for infarct size.
The LGE protocol presented provides a reliable method for acquiring images of high contrast and quality without excessive scan times, enabling higher throughput in experimental studies requiring reliable assessment of MI.
心肌梗死（MI）可以通过晚期钆增强（LGE）心血管磁共振（CMR）进行快速评估。反转恢复（IR）序列可在增强的梗死区域和健康心肌之间提供最高的对比度。由于相对于 T1 弛豫，小动物的呼吸和心脏速率较快，因此应用此类方法具有挑战性。
在这里，我们提出了一种使用多切片 IR 梯度回波序列评估小动物 LGE 的快速而稳健的协议，用于高效评估 LGE。附加的 Look-Locker 序列用于在个体基础上评估最佳反转点，并确定大鼠和小鼠的最合适门控点。该技术应用于两个临床前场景：i）大鼠急性（2 小时）再灌注 MI 模型和 ii）非再灌注 MI 后 2 天的小鼠。
所有动物的 LGE 图像均显示出清晰的增强区域，便于进行体积分割。在大鼠中使健康心肌无效所需的典型反转时间在 300-450 毫秒之间，相当于 2-3 个 R 波，而在小鼠中约为 330 毫秒，反转后通常为 3 个 R 波。大鼠的数据也与三苯基四唑氯化物染色进行了验证，并且梗死面积的结果非常吻合。
所提出的 LGE 方案提供了一种可靠的方法，可以在不增加扫描时间的情况下获得高对比度和高质量的图像，从而在需要可靠评估 MI 的实验研究中实现更高的通量。
