Department of Radiology, University of Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, AB, Canada; Alberta Children's Hospital Research Institute, University of Calgary, 28 Oki Drive, Calgary, AB T3B 6A9, Canada.
Department of Radiology, University of Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, AB, Canada; Alberta Children's Hospital Research Institute, University of Calgary, 28 Oki Drive, Calgary, AB T3B 6A9, Canada.
Neuroimage. 2022 Aug 15;257:119330. doi: 10.1016/j.neuroimage.2022.119330. Epub 2022 May 24.
Magnetic resonance spectroscopy (MRS) is a non-invasive neuroimaging technique used to measure brain chemistry in vivo and has been used to study the healthy brain as well as neuropathology in numerous neurological disorders. The number of multi-site studies using MRS are increasing; however, non-biological variability introduced during data collection across multiple sites, such as differences in scanner vendors and site-specific acquisition implementations for MRS, can obscure detection of biological effects of interest. ComBat is a data harmonization technique that can remove non-biological sources of variance in multisite studies. It has been validated for use with structural and functional MRI metrics but not for MRS measured metabolites. This study investigated the validity of using ComBat to harmonize MRS metabolites for vendor and site differences. Analyses were performed using data acquired across 20 sites and included edited MRS for GABA+ (N = 218) and macromolecule-suppressed GABA data (N = 209), as well as standard PRESS data to quantify NAA, creatine, choline, and glutamate (N = 190). ComBat harmonization successfully mitigated vendor and site differences for all metabolites of interest. Moreover, significant associations were detected between sex and choline levels and between age and glutamate and GABA+ levels that were not detectable prior to harmonization, confirming the importance of removing site and vendor effects in multi-site data. In conclusion, ComBat harmonization can be successfully applied to MRS data in multi-site MRS studies.
磁共振波谱（MRS）是一种非侵入性的神经影像学技术，用于测量体内的脑化学物质，已被用于研究健康大脑以及许多神经疾病中的神经病理学。使用 MRS 的多站点研究数量正在增加；然而，在多个站点采集数据期间引入的非生物学变异性，例如扫描仪供应商的差异和 MRS 的特定站点采集实现，可能会掩盖对感兴趣的生物学效应的检测。ComBat 是一种数据协调技术，可以消除多站点研究中非生物学来源的方差。它已被验证可用于结构和功能 MRI 指标，但不能用于测量 MRS 代谢物。本研究调查了使用 ComBat 协调 MRS 代谢物以消除供应商和站点差异的有效性。使用在 20 个站点采集的数据进行了分析，包括编辑的 GABA+（N=218）和大分子抑制 GABA 数据（N=209）以及标准 PRESS 数据，以定量 NAA、肌酸、胆碱和谷氨酸（N=190）。ComBat 协调成功地减轻了所有感兴趣代谢物的供应商和站点差异。此外，在协调之前无法检测到的性别与胆碱水平之间以及年龄与谷氨酸和 GABA+水平之间存在显著关联，证实了在多站点数据中消除站点和供应商效应的重要性。总之，ComBat 协调可以成功应用于多站点 MRS 研究中的 MRS 数据。
