Introduction

Myocardial infarction is one of the major causes of death and disability. Various diagnostic modalities used to investigate cardiac ischaemia. Advances in Magnetic Resonance Imaging technology has opened up new horizons for investigating the cardiac function and quantifying any pathology that may be present.

Aims

The present study was designed to quantify the cardiac area at risk and infarction reperfusion areas using the mismatch of iron oxide contrast and gadolinium (Gd) contrast imaging (MRIs) and to test if a combination of T1, T2, and iron oxide T2* contrasts will distinguish the infarction and AAR zones.

Methods

A well-established mouse model was used to induced cardiac ischaemia and reperfusion. Six mice models’ hearts were harvested and processed according to various protocols. MI was induced through ligation technique for five mice, and one was kept as normal control. MR imaging and Reperfusion were performed using a Three-dimensional gradient-echo fast low angle shot (3DFLASH) and three-dimensional multi-slice multi-echo sequence (3DMSME). Generation of T1 and T2 maps, image post-processing including segmentation and mismatch measurement and drawing of the area of interest.

Results

The edematous myocardium had significant high signal intensity in 3DMSME with variable echo time (14, 28, 42 ms). The combination of 3DFLASH and 3DMSME at an echo time of 42 ms was statistically significant, detecting the AAR more accurately. Both T1 and T2 sequences had the potential to determine the AAR zone. The infarct area has significantly high signal intensity compared to normal areas (p = 0.04 for the T1 map and p = 0.01 for the T2 map).

Conclusions

The study demonstrated that Cardiac MRI was a valuable technology to investigate infarct areas and zones that are at risk.

中文翻译：

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离体小鼠心脏缺血模型的MR图像分析

介绍

心肌梗塞是导致死亡和残疾的主要原因之一。用于调查心脏缺血的各种诊断方式。磁共振成像技术的进步为研究心脏功能和量化可能存在的任何病理开辟了新的视野。

目标

本研究旨在使用氧化铁对比和钆 (Gd) 对比成像 (MRI) 的不匹配来量化有风险的心脏区域和梗死再灌注区域，并测试 T1、T2 和氧化铁 T2* 对比的组合是否将区分梗死区和 AAR 区。

方法

使用成熟的小鼠模型来诱导心脏缺血和再灌注。根据各种协议收获和处理六只小鼠模型的心脏。5只小鼠通过结扎技术诱导心肌梗死，1只作为正常对照。使用三维梯度回波快速低角度拍摄( 3DFLASH) 和三维多切片多回波序列 (3DMSME) 进行 MR 成像和再灌注。生成 T1 和 T2 图，图像后处理包括分割和不匹配测量以及感兴趣区域的绘制。

结果

水肿心肌在 3DMSME 中具有显着的高信号强度，回声时间可变（14、28、42 ms）。3DFLASH 和 3DMSME 在 42 ms 回波时间的组合具有统计学意义，更准确地检测 AAR。T1 和 T2 序列都有可能确定 AAR 区。与正常区域相比，梗塞区域具有显着高的信号强度（T1 图 p = 0.04，T2 图 p = 0.01）。

结论

该研究表明，心脏 MRI 是一项有价值的技术，可用于调查有风险的梗塞区域和区域。