Brainstem Imaging Laboratory, Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
Brain Connect. 2021 Oct;11(8):613-623. doi: 10.1089/brain.2020.0975. Epub 2021 Jun 17.
The mesencephalic reticular formation, isthmic reticular formation, microcellular tegmental nucleus, ventral tegmental area-parabrachial pigmented nucleus complex, and caudal-rostral linear nucleus of the raphe are small brainstem regions crucially involved in arousal, sleep, and reward. Yet, these nuclei are difficult to identify with magnetic resonance imaging (MRI) of living humans. In the current work, we developed a probabilistic atlas of these brainstem nuclei in living humans, using noninvasive ultra-high-field MRI. We acquired single-subject, multicontrast (diffusion and T-weighted), 1.1-mm isotropic resolution, 7 Tesla MRI images of 12 healthy subjects. After preprocessing and alignment to the stereotactic space, these images were used to delineate (in each subject) the nuclei of interest based on the image contrast as well as on neighboring nuclei and landmarks. Nucleus labels were averaged across subjects to yield probabilistic labels. The latter were further validated by assessment of the label inter-rater agreement, internal consistency, and volume. Labels were delineated for each nucleus with good overlap across subjects. The inter-rater agreement and internal consistency were below ( < 10) the linear spatial imaging resolution (1.1 mm), thus validating the generated probabilistic atlas labels. The volumes of our labels did not differ from literature volumes ( < 0.05), further validating our atlas. The probabilistic atlas of these five mesopontine nuclei expands current brainstem nuclei atlases and can be used as a tool to identify the location of these areas in conventional (e.g., 3 Tesla) images. This might serve to unravel the brainstem structure-to-function link and thus improve clinical outcomes. Impact statement The mesencephalic reticular formation, isthmic reticular formation, microcellular tegmental nucleus, ventral tegmental area-parabrachial pigmented nucleus complex, and caudal-rostral linear nucleus of the raphe are small brainstem regions crucially involved in arousal, sleep, and reward. In the current work, we developed a probabilistic atlas of these brainstem nuclei in living humans, using noninvasive, ultra-high-field magnetic resonance imaging. The probabilistic atlas of these five mesopontine nuclei expands current brainstem nuclei atlases and can be used as a tool to identify the location of these areas in conventional (e.g., 3 Tesla) images. This might serve to unravel the brainstem structure-to-function link and thus improve clinical outcomes.
中脑网状结构、脑桥网状结构、微细胞被盖核、腹侧被盖区-臂旁色素核复合体和中缝背核嘴侧尾侧线性核是与觉醒、睡眠和奖励密切相关的小脑干区域。然而，这些核团在活体人类的磁共振成像（MRI）中很难识别。在当前的工作中，我们使用非侵入性超高场 MRI 开发了活体人类这些脑干核团的概率图谱。我们获得了 12 名健康受试者的单个体、多对比度（扩散和 T 加权）、1.1 毫米各向同性分辨率、7 特斯拉 MRI 图像。在预处理和配准到立体定向空间后，这些图像用于根据图像对比度以及相邻核团和地标来描绘（每个受试者）感兴趣的核团。根据受试者的平均值生成概率标签。通过评估标签的组内一致性、内部一致性和体积，进一步验证了这些标签。标签在每个核团的描绘中具有良好的受试者间重叠。组内一致性和内部一致性低于（<10）线性空间成像分辨率（1.1 毫米），从而验证了生成的概率图谱标签。我们的标签体积与文献体积（<0.05）无差异，进一步验证了我们的图谱。该概率图谱包括 5 个中脑脑桥核团，扩展了当前的脑干核团图谱，并可用于识别常规（例如 3 特斯拉）图像中这些区域的位置。这可能有助于揭示脑干结构-功能关系，从而改善临床结果。
