School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
Centre for Advanced MRI, Auckland UniServices Limited, Auckland, New Zealand.
J Magn Reson Imaging. 2024 May;59(5):1683-1694. doi: 10.1002/jmri.28938. Epub 2023 Aug 4.
The role of neuroinflammation in psychiatric disorders is not well-elucidated. A noninvasive technique sensitive to low-level neuroinflammation may improve understanding of the pathophysiology of these conditions.
To test the ability of quantitative magnetization transfer (QMT) MR at 3 T for detection of low-level neuroinflammation induced by typhoid vaccine within a clinically reasonable scan time.
Randomized, crossover, placebo-controlled.
Twenty healthy volunteers (10 males; median age 34 years).
FIELD STRENGTH/SEQUENCE: Magnetization prepared rapid gradient-echo and MT-weighted 3D fast low-angle shot sequences at 3 T.
Participants were randomized to either vaccine or placebo first with imaging, then after a washout period received the converse with a second set of imaging. MT imaging, scan time, and blood-based inflammatory marker concentrations were assessed pre- and post-vaccine and placebo. Mood was assessed hourly using the Profile of Mood States questionnaire. QMT parameter maps, including the exchange rate from bound to free pool (k) were generated using a two-pool model and then segmented into tissue type.
Voxel-wise permutation-based analysis examined inflammatory-related alterations of QMT parameters. The threshold-free cluster enhancement method with family-wise error was used to correct voxel-wise results for multiple comparisons. Region of interest averages were fed into mixed models and Bonferroni corrected. Spearman correlations assessed the relationship between mood scores and QMT parameters. Results were considered significant if corrected P < 0.05.
Scan time for the MT-weighted acquisition was approximately 11 minutes. Blood-based analysis showed higher IL-6 concentrations post-vaccine compared to post-placebo. Voxel-wise analysis found three clusters indicating an inflammatory-mediated increase in k in cerebellar white matter. Cerebellar k for white matter was negatively associated with vigor post-vaccine but not post-placebo.
This study suggested that QMT at 3 T may show some sensitivity to low-level neuroinflammation. Further studies are needed to assess the viability of QMT for use in inflammatory-based disorders.
1 TECHNICAL EFFICACY: Stage 2.
神经炎症在精神疾病中的作用尚不清楚。一种对低水平神经炎症敏感的非侵入性技术可能有助于更好地理解这些疾病的病理生理学。
在临床可接受的扫描时间内，测试 3T 下定量磁化传递（QMT）MR 检测伤寒疫苗诱导的低水平神经炎症的能力。
随机、交叉、安慰剂对照。
20 名健康志愿者（10 名男性；中位年龄 34 岁）。
磁场强度/序列：3T 下的磁化准备快速梯度回波和 MT 加权 3D 快速低角度 shot 序列。
参与者随机分为疫苗组或安慰剂组，先进行影像学检查，然后在洗脱期后接受相反的检查，进行第二组影像学检查。在接种疫苗和安慰剂前后评估 MT 成像、扫描时间和基于血液的炎症标志物浓度。使用心境状态问卷（Profile of Mood States questionnaire）每小时评估一次情绪。使用双池模型生成包括从结合池到游离池的交换率（k）的 QMT 参数图，然后将其分割为组织类型。
体素置换基分析检验了 QMT 参数与炎症相关的变化。采用无阈值聚类增强方法（family-wise error）对体素水平的结果进行多重比较校正。将感兴趣区平均值输入混合模型并进行 Bonferroni 校正。Spearman 相关性评估了情绪评分与 QMT 参数之间的关系。如果校正后的 P 值<0.05，则认为结果具有统计学意义。
MT 加权采集的扫描时间约为 11 分钟。基于血液的分析显示，接种疫苗后白细胞介素 6（IL-6）浓度高于接种安慰剂后。体素分析发现三个簇表明小脑白质中存在炎症介导的 k 增加。小脑白质的 k 与接种疫苗后的活力呈负相关，但与接种安慰剂后无关。
本研究表明，3T 下的 QMT 可能对低水平神经炎症有一定的敏感性。需要进一步的研究来评估 QMT 在炎症相关疾病中的应用可行性。
1 技术功效：第 2 阶段。
