Background: Magnetic resonance spectroscopic imaging (MRSI) is a neuroimaging technique that may be useful for non-invasive mapping of brain temperature (i.e., thermometry) over a large brain volume. To date, intra-subject reproducibility of MRSI-based brain temperature (MRSI-t) has not been investigated. The objective of this repeated measures MRSI-t study was to establish intra-subject reproducibility and repeatability of brain temperature, as well as typical brain temperature range. Methods: Healthy participants aged 23–46 years (N = 18; 7 females) were scanned at two time points ~12-weeks apart. Volumetric MRSI data were processed by reconstructing metabolite and water images using parametric spectral analysis. Brain temperature was derived using the frequency difference between water and creatine (TCRE) for 47 regions of interest (ROIs) delineated by the modified Automated Anatomical Labeling (AAL) atlas. Reproducibility was measured using the coefficient of variation for repeated measures (COVrep), and repeatability was determined using the standard error of measurement (SEM). For each region, the upper and lower bounds of Minimal Detectable Change (MDC) were established to characterize the typical range of TCRE values. Results: The mean global brain temperature over all subjects was 37.2°C with spatial variations across ROIs. There was a significant main effect for time [F(1, 1,591) = 37.0, p < 0.0001] and for brain region [F(46, 1,591) = 2.66, p < 0.0001]. The time*brain region interaction was not significant [F(46, 1,591) = 0.80, p = 0.83]. Participants' TCRE was stable for each ROI across both time points, with ROIs' COVrep ranging from 0.81 to 3.08% (mean COVrep = 1.92%); majority of ROIs had a COVrep <2.0%. Conclusions: Brain temperature measurements were highly consistent between both time points, indicating high reproducibility and repeatability of MRSI-t. MRSI-t may be a promising diagnostic, prognostic, and therapeutic tool for non-invasively monitoring brain temperature changes in health and disease. However, further studies of healthy participants with larger sample size(s) and numerous repeated acquisitions are imperative for establishing a reference range of typical brain TCRE, as well as the threshold above which TCRE is likely pathological.

中文翻译：

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体内脑温度测量的重复性和再现性


背景：磁共振波谱成像（MRSI）是一种神经成像技术，可用于无创地绘制大脑体积内的脑温度（即测温）。迄今为止，尚未对基于 MRSI 的脑温度 (MRSI-t) 的受试者内再现性进行研究。这项重复测量 MRSI-t 研究的目的是确定受试者体内脑温度的再现性和可重复性，以及典型的脑温度范围。方法：对年龄 23-46 岁的健康参与者（N = 18；7 名女性）在相隔约 12 周的两个时间点进行扫描。通过使用参数光谱分析重建代谢物和水图像来处理体积 MRSI 数据。利用修改后的自动解剖标记 (AAL) 图集描绘的 47 个感兴趣区域 (ROI) 的水和肌酸 (TCRE) 之间的频率差得出脑温度。使用重复测量变异系数 (COVrep) 测量再现性，并使用测量标准误差 (SEM) 确定重复性。对于每个区域，建立了最小可检测变化 (MDC) 的上限和下限来表征 TCRE 值的典型范围。结果：所有受试者的平均整体脑温度为 37.2°C，不同 ROI 存在空间差异。时间 [F(1, 1,591) = 37.0, p < 0.0001] 和大脑区域 [F(46, 1,591) = 2.66, p < 0.0001] 有显着的主效应。时间*大脑区域交互作用不显着 [F(46, 1,591) = 0.80, p = 0.83]。参与者的 TCRE 在两个时间点上对于每个 ROI 都是稳定的，ROI 的 COVrep 范围为 0.81 至 3.08%（平均 COVrep = 1.92%）；大多数 ROI 的 COVrep <2.0%。 结论：两个时间点之间的脑温度测量结果高度一致，表明 MRSI-t 具有较高的再现性和可重复性。 MRSI-t 可能是一种有前途的诊断、预后和治疗工具，用于无创监测健康和疾病时的脑部温度变化。然而，对于建立典型大脑 TCRE 的参考范围以及 TCRE 可能病理的阈值，需要对健康参与者进行更大样本量和大量重复采集的进一步研究。