Reliability of the depth-dependent high-resolution BOLD hemodynamic response in human visual cortex and vicinity.
Reliability of the depth-dependent high-resolution BOLD hemodynamic response in human visual cortex and vicinity.
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DOI：
10.1016/j.mri.2017.01.019
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发表时间：
2017-06
影响因子：
2.5
通讯作者：
Ress D
中科院分区：
文献类型：
--
作者：
Kim JH;Ress D
功能磁共振成像 (fMRI) 通常依赖于血流动力学响应函数 (HRF)，即由短暂（<4 秒）刺激引起的典型血氧水平依赖性 (BOLD) 响应。 HRF 的早期测量使用粗空间分辨率（≥3 mm 体素），通常包括每个体素内白质、灰质和软脑膜外室（软脑膜表面和颅骨之间的空间，包括软脑膜血管）的贡献。为了解决这些问题，我们在 3T 下对早期视觉皮层及其相应的白质和软脑膜外区室进行了高分辨率功能磁共振成像（0.9 毫米体素）。结果表征了九次功能磁共振成像期间 HRF 的深度依赖性及其可靠性。在白质和软脑膜外区以及灰质中观察到显着的 HRF。白质 HRF 比灰质更快、更弱，而软脑膜外 HRF 相对更慢、更强。 HRF 峰值幅度的深度趋势在整个深度范围内保持稳定，其中包括每次会话的所有三个隔室。然而，在各个疗程中，HRF 峰值幅度的深度趋势仅在白质和深中灰质中稳定，而浅层灰质和软脑膜外室则存在强烈的疗程间变化。因此，高分辨率功能磁共振成像可以解析灰质、白质和软膜外区室中显着且动态不同的 HRF。
Functional magnetic resonance imaging (fMRI) often relies on a hemodynamic response function (HRF), the stereotypical blood oxygen level dependent (BOLD) response elicited by a brief (<4 seconds) stimulus. Early measurements of the HRF used coarse spatial resolutions (≥3 mm voxels) that would generally include contributions from white matter, gray matter, and the extra-pial compartment (the space between the pial surface and skull including pial blood vessels) within each voxel. To resolve these contributions, high-resolution fMRI (0.9-mm voxels) was performed at 3T in early visual cortex and its apposed white-matter and extra-pial compartments. The results characterized the depth dependence of the HRF and its reliability during nine fMRI sessions. Significant HRFs were observed in white-matter and extra-pial compartments as well as in gray matter. White-matter HRFs were faster and weaker than in the gray matter, while extra-pial HRFs were comparatively slower and stronger. Depth trends of the HRF peak amplitude were stable throughout a broad depth range that included all three compartments for each session. Across sessions, however, the depth trend of HRF peak amplitudes was stable only in the white matter and deep-intermediate gray matter, while there were strong session-to-session variations in the superficial gray matter and the extra-pial compartment. Thus, high-resolution fMRI can resolve significant and dynamically distinct HRFs in gray matter, white matter, and extra-pial compartments.