Clear and Consistent Imaging of Hippocampal Internal Architecture With High Resolution Multiple Image Co-registration and Averaging (HR-MICRA).
Clear and Consistent Imaging of Hippocampal Internal Architecture With High Resolution Multiple Image Co-registration and Averaging (HR-MICRA).
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DOI：
10.3389/fnins.2021.546312
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发表时间：
2021
影响因子：
4.3
通讯作者：
Szaflarski JP
中科院分区：
文献类型：
--
作者：
Ver Hoef L;Deshpande H;Cure J;Selladurai G;Beattie J;Kennedy RE;Knowlton RC;Szaflarski JP
海马内部结构（HIA）的3 T磁共振成像具有挑战性。HIA由冠状面中厚度小于1 mm的灰色和白色物质层定义。为了可视化HIA，常规MRI方法依赖于具有高平面内分辨率（≤0.5 mm）但相对较厚切片（2-5 mm）的序列。然而，较厚的切片容易产生体积平均效应，导致高达61%的切片中HIA清晰度丧失和海马子场边界模糊。在这项工作中，我们描述了一种海马成像的方法，提供一贯的高HIA清晰度使用一个常用的序列和后处理技术，是灵活的，可适用于任何MRI平台。我们将这种方法称为高分辨率多图像配准和平均（HR-MICRA）。该方法使用可变翻转角快速自旋回波序列在相对较短的时间内重复采集具有三维高分辨率的全脑T2 w图像体积，然后共同配准体积以校正移动并对重复扫描进行平均以提高SNR。我们使用已发表的HIA清晰度评级量表比较了20名健康对照者的4、9和16次单独扫描的平均值。在海马体中，16倍、9倍和4倍HR-MICRA图像的HIA清晰度良好或极佳的切片比例分别为90%、83%和67%。使用4x HR-MICRA图像作为基线，9 x HR-MICRA图像是2.6倍，16 x HR-MICRA图像是3.2倍，在所有海马段（头部，身体和尾部）中具有高HIA评级的可能性（p < 0.001）。HR-MICRA图像的薄切片允许在任何平面中重新格式化，并在矢状面中清晰显示海马齿状突起。清晰和一致的可视化HIA将允许这种技术应用于未来的海马结构研究，以及更精确的手动或自动分割。
Magnetic resonance imaging of hippocampal internal architecture (HIA) at 3T is challenging. HIA is defined by layers of gray and white matter that are less than 1 mm thick in the coronal plane. To visualize HIA, conventional MRI approaches have relied on sequences with high in-plane resolution (≤0.5 mm) but comparatively thick slices (2–5 mm). However, thicker slices are prone to volume averaging effects that result in loss of HIA clarity and blurring of the borders of the hippocampal subfields in up to 61% of slices as has been reported. In this work we describe an approach to hippocampal imaging that provides consistently high HIA clarity using a commonly available sequence and post-processing techniques that is flexible and may be applicable to any MRI platform. We refer to this approach as High Resolution Multiple Image Co-registration and Averaging (HR-MICRA). This approach uses a variable flip angle turbo spin echo sequence to repeatedly acquire a whole brain T2w image volume with high resolution in three dimensions in a relatively short amount of time, and then co-register the volumes to correct for movement and average the repeated scans to improve SNR. We compared the averages of 4, 9, and 16 individual scans in 20 healthy controls using a published HIA clarity rating scale. In the body of the hippocampus, the proportion of slices with good or excellent HIA clarity was 90%, 83%, and 67% for the 16x, 9x, and 4x HR-MICRA images, respectively. Using the 4x HR-MICRA images as a baseline, the 9x HR-MICRA images were 2.6 times and 16x HR-MICRA images were 3.2 times more likely to have high HIA ratings (p < 0.001) across all hippocampal segments (head, body, and tail). The thin slices of the HR-MICRA images allow reformatting in any plane with clear visualization of hippocampal dentation in the sagittal plane. Clear and consistent visualization of HIA will allow application of this technique to future hippocampal structure research, as well as more precise manual or automated segmentation.
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影响因子：
5.7
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通讯作者：
Smith, S
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Ver Hoef L
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作者：
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