Imaging Research Laboratories, Robarts Research Institute - Western University, London, Ontario, Canada.
Epilepsy Program, Department of Clinical Neurological Sciences, Schulich School of Medicine - Western University, London, Ontario, Canada.
J Magn Reson Imaging. 2018 Dec;48(6):1529-1539. doi: 10.1002/jmri.26013. Epub 2018 Mar 23.
Connectivity studies targeting the thalamus have revealed patterns of atrophy and deafferentiation in temporal lobe epilepsy (TLE). The thalamus can be parcellated using probabilistic tractography to demonstrate regions of cortical connectivity; however, sensitivity to smaller or less connected regions is low.
PURPOSE/HYPOTHESIS: To investigate thalamic structural connectivity in a wider range of cortical and limbic structures in TLE patients using a novel connectivity map normalization procedure.
Retrospective.
POPULATION/SUBJECTS: Patients (N = 23) with medication-resistant TLE and 34 healthy age-matched controls.
FIELD STRENGTH/SEQUENCE: For T and diffusion weighting a spoiled gradient sequence was used (41 gradient directions [b = 1000]). For T mapping balanced steady-state free precession was used. Images were acquired at 3T.
Probabilistic tractography and a novel normalization procedure allowed comparison of groups with respect to thalamic connected volume, quantitative MRI, and diffusion tensor imaging (DTI) metrics.
Independent samples t-test, Cohen's d, and Mann-Whitney tests.
Following normalization, significant differences in thalamic connected volumes were found in left TLE vs. controls bilaterally within the posterior parahippocampal gyrus (L: P = 0.007, confidence interval [CI]: [173.306,1044.41], effect size [ES] = 1.072; R: P = 0.017, CI: [98.677,947.653], ES = 0.945), and contralaterally in the anterior temporal neocortex (P = 0.01, CI: (-2348.09, -333.719), ES = -1.021). This procedure revealed differences in thalamic connected volumes, where previously published procedures could not, and provided a basis for exploratory analysis of quantitative MRI and DTI metrics.
The novel connectivity map normalization scheme proposed here successfully allowed comparison between a wider range of cortical and limbic structures. Multiple volumetric and quantitative MRI and DTI-related differences between TLE patients and controls were revealed following normalization. With validation from a larger cohort, thalamo-temporal connection aberrancies may become useful biomarkers of disease states and probabilistic tractography as a procedure for identification of thalamic targets in modulatory therapies for TLE.
3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1529-1539.
针对丘脑的连通性研究揭示了颞叶癫痫（TLE）中存在萎缩和去传入现象。使用概率追踪技术可以将丘脑划分为多个区域，以显示皮质连通性的区域；然而，对较小或连通性较低的区域的敏感性较低。
目的/假设：使用一种新的连通图归一化程序，研究 TLE 患者更广泛的皮质和边缘结构的丘脑结构连通性。
回顾性。
人群/受试者：（N=23）名药物难治性 TLE 患者和 34 名年龄匹配的健康对照者。
场强/序列：T 加权和扩散加权采用扰动脉冲序列（41 个梯度方向[b=1000]）。T 映射采用平衡稳态自由进动。在 3T 上采集图像。
概率追踪和一种新的归一化程序允许根据丘脑连接体积、定量 MRI 和弥散张量成像（DTI）指标对组进行比较。
独立样本 t 检验、Cohen's d 和 Mann-Whitney 检验。
归一化后，在左 TLE 患者双侧后海马旁回（L：P=0.007，置信区间[CI]：[173.306，1044.41]，效应量[ES]=1.072）和对侧前颞叶新皮质（P=0.01，CI：（-2348.09，-333.719），ES=-1.021）中发现丘脑连接体积存在显著差异。该程序揭示了以前的程序无法揭示的丘脑连接体积差异，并为定量 MRI 和 DTI 指标的探索性分析提供了基础。
这里提出的新连通图归一化方案成功地允许在更广泛的皮质和边缘结构之间进行比较。在 TLE 患者和对照组之间，通过归一化后发现了多个体积和定量 MRI 和 DTI 相关的差异。通过更大队列的验证，丘脑-颞叶连接异常可能成为疾病状态的有用生物标志物，并使概率追踪成为 TLE 调制治疗中确定丘脑靶点的程序。
3 技术功效：阶段 2 J. Magn. Reson. Imaging 2018;48:1529-1539.
