Table_1_DiMANI: diffusion MRI for anatomical nuclei imaging—Application for the direct visualization of thalamic subnuclei.DOCX

The thalamus is a centrally located and heterogeneous brain structure that plays a critical role in various sensory, motor, and cognitive processes. However, visualizing the individual subnuclei of the thalamus using conventional MRI techniques is challenging. This difficulty has posed obstacles in targeting specific subnuclei for clinical interventions such as deep brain stimulation (DBS). In this paper, we present DiMANI, a novel method for directly visualizing the thalamic subnuclei using diffusion MRI (dMRI). The DiMANI contrast is computed by averaging, voxelwise, diffusion-weighted volumes enabling the direct distinction of thalamic subnuclei in individuals. We evaluated the reproducibility of DiMANI through multiple approaches. First, we utilized a unique dataset comprising 8 scans of a single participant collected over a 3-year period. Secondly, we quantitatively assessed manual segmentations of thalamic subnuclei for both intra-rater and inter-rater reliability. Thirdly, we qualitatively correlated DiMANI imaging data from several patients with Essential Tremor with the localization of implanted DBS electrodes and clinical observations. Lastly, we demonstrated that DiMANI can provide similar features at 3T and 7T MRI, using varying numbers of diffusion directions. Our results establish that DiMANI is a reproducible and clinically relevant method to directly visualize thalamic subnuclei. This has significant implications for the development of new DBS targets and the optimization of DBS therapy.

丘脑是位于脑内中央的异质性脑结构，在多种感觉、运动及认知过程中发挥关键作用。然而，利用常规磁共振成像（Magnetic Resonance Imaging, MRI）技术可视化丘脑的单个亚核颇具挑战，这一难题为针对特定丘脑亚核开展脑深部电刺激（Deep Brain Stimulation, DBS）等临床干预操作带来了阻碍。本研究提出了DiMANI这一全新方法，可利用弥散磁共振成像（diffusion MRI, dMRI）直接可视化丘脑亚核。DiMANI对比信号通过逐体素平均弥散加权成像容积得到计算结果，可实现个体水平丘脑亚核的直接区分。本研究通过多种方式评估了DiMANI的可重复性：其一，我们使用了一项独特的数据集，该数据集包含一名受试者在3年时间内完成的8次扫描结果；其二，我们针对丘脑亚核的手动分割操作，定量评估了评分者内信度与评分者间信度；其三，我们将数名特发性震颤（Essential Tremor）患者的DiMANI成像数据与植入的脑深部电刺激电极定位及临床观察结果进行了定性关联分析；最后，我们证实，在3T与7T磁共振成像设备下，无论弥散方向数量如何变化，DiMANI均可获得相似的成像特征。本研究结果证实，DiMANI是一种具备可重复性且具有临床应用价值的丘脑亚核直接可视化方法，该方法对于新型脑深部电刺激靶点的开发以及脑深部电刺激治疗方案的优化具有重要意义。