Objective

The aim of the study is to compare structure tensor imaging (STI) with diffusion tensor imaging (DTI) of the sheep heart (approximately the same size as the human heart).

Materials and methods

MRI acquisition on three sheep ex vivo hearts was performed at 9.4 T/30 cm with a seven-element RF coil. 3D FLASH with an isotropic resolution of 150 µm and 3D spin-echo DTI at 600 µm were performed. Tensor analysis, angles extraction and segments divisions were performed on both volumes.

Results

A 3D FLASH allows for visualization of the detailed structure of the left and right ventricles. The helix angle determined using DTI and STI exhibited a smooth transmural change from the endocardium to the epicardium. Both the helix and transverse angles were similar between techniques. Sheetlet organization exhibited the same pattern in both acquisitions, but local angle differences were seen and identified in 17 segments representation.

Discussion

This study demonstrated the feasibility of high-resolution MRI for studying the myocyte and myolaminar architecture of sheep hearts. We presented the results of STI on three whole sheep ex vivo hearts and demonstrated a good correspondence between DTI and STI.

中文翻译：

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具有亚毫米各向同性空间分辨率的外植羊心脏的 3D MRI：扩散张量和结构张量成像的比较

客观的

该研究的目的是比较绵羊心脏（与人类心脏大小大致相同）的结构张量成像 (STI) 和扩散张量成像 (DTI)。

材料和方法

三只羊离体心脏的 MRI 采集是在 9.4 T/30 cm 下使用七元素射频线圈进行的。执行了各向同性分辨率为 150 µm 的 3D FLASH 和 600 µm 的 3D 自旋回波 DTI。对两个体积都进行了张量分析、角度提取和分段分割。

结果

3D FLASH 可以显示左右心室的详细结构。使用 DTI 和 STI 确定的螺旋角表现出从心内膜到心外膜的平滑透壁变化。技术之间的螺旋角和横向角都相似。Sheetlet 组织在两次收购中都表现出相同的模式，但在 17 个片段表示中可以看到并识别出局部角度差异。

讨论

这项研究证明了高分辨率 MRI 用于研究绵羊心脏的肌细胞和肌层结构的可行性。我们在三只全羊离体心脏上展示了 STI 的结果，并证明了 DTI 和 STI 之间的良好对应关系。