From the High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Lazarettgasse 14, A-1090 Vienna, Austria (E.H., B.S., G.J.H., A.L., S.M., L.H., S.G., S.T., W.B.); Departments of Neurology (A.D.B., P.S.R., T.B., F.L.) and Neurosurgery (G.J.H.), Medical University of Vienna, Vienna, Austria; Biomedical Center Martin (P.H.) and Clinic of Neurology (E. Kantorová, E. Kurča), Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia; and Karl Landsteiner Institute for Clinical Molecular MRI in Musculoskeletal System, Vienna, Austria (S.T.).
Radiology. 2022 Apr;303(1):141-150. doi: 10.1148/radiol.210614. Epub 2022 Jan 4.
Background MR spectroscopic imaging (MRSI) allows in vivo assessment of brain metabolism and is of special interest in multiple sclerosis (MS), where morphologic MRI cannot depict major parts of disease activity. Purpose To evaluate the ability of 7.0-T MRSI to depict and visualize pathologic alterations in the normal-appearing white matter (NAWM) and cortical gray matter (CGM) in participants with MS and to investigate their relation to disability. Materials and Methods Free-induction decay MRSI was performed at 7.0 T. Participants with MS and age- and sex-matched healthy controls were recruited prospectively between January 2016 and December 2017. Metabolic ratios were obtained in white matter lesions, NAWM, and CGM regions. Subgroup analysis for MS-related disability based on Expanded Disability Status Scale (EDSS) scores was performed using analysis of covariance. Partial correlations were applied to explore associations between metabolic ratios and disability. Results Sixty-five participants with MS (mean age ± standard deviation, 34 years ± 9; 34 women) and 20 age- and sex-matched healthy controls (mean age, 32 years ± 7; 11 women) were evaluated. Higher signal intensity of myo-inositol (mI) with and without reduced signal intensity of -acetylaspartate (NAA) was visible on metabolic images in the NAWM of participants with MS. A higher ratio of mI to total creatine (tCr) was observed in the NAWM of the centrum semiovale of all MS subgroups, including participants without disability (marginal mean ± standard error, healthy controls: 0.78 ± 0.04; EDSS 0-1: 0.86 ± 0.03 [ = .02]; EDSS 1.5-3: 0.95 ± 0.04 [ < .001]; EDSS ≥3.5: 0.94 ± 0.04 [ = .001]). A lower ratio of NAA to tCr was found in MS subgroups with disabilities, both in their NAWM (marginal mean ± standard error, healthy controls: 1.46 ± 0.04; EDSS 1.5-3: 1.33 ± 0.03 [ = .03]; EDSS ≥3.5: 1.30 ± 0.04 [ = .01]) and CGM (marginal mean ± standard error, healthy controls: 1.42 ± 0.05; EDSS ≥3.5: 1.23 ± 0.05 [ = .006]). mI/NAA correlated with EDSS (NAWM of centrum semiovale: = 0.47, < .001; parietal NAWM: = 0.43, = .002; frontal NAWM: = 0.34, = .01; frontal CGM: = 0.37, = .004). Conclusion MR spectroscopic imaging at 7.0 T allowed in vivo visualization of multiple sclerosis pathologic findings not visible at T1- or T2-weighted MRI. Metabolic abnormalities in the normal-appearing white matter and cortical gray matter were associated with disability. © RSNA, 2022 See also the editorial by Barker in this issue.
背景 磁共振波谱成象（MRSI）允许对脑代谢进行体内评估，在多发性硬化症（MS）中尤为重要，因为形态 MRI 不能显示疾病活动的主要部分。目的 评估 7.0-T MRSI 在 MS 患者的正常表现白质（NAWM）和皮质灰质（CGM）中描绘和可视化病理改变的能力，并研究其与残疾的关系。材料与方法 在 7.0 T 上进行自由感应衰减 MRSI。前瞻性招募 2016 年 1 月至 2017 年 12 月的 MS 患者和年龄、性别匹配的健康对照者。在白质病变、NAWM 和 CGM 区域获得代谢比率。基于扩展残疾状态量表（EDSS）评分的 MS 相关残疾亚组分析采用协方差分析。应用偏相关探讨代谢比率与残疾之间的关系。结果 共评估了 65 名 MS 患者（平均年龄±标准差，34 岁±9；34 名女性）和 20 名年龄、性别匹配的健康对照者（平均年龄，32 岁±7；11 名女性）。在 MS 患者的 NAWM 中，代谢图像上可见肌醇（mI）信号强度升高，伴 N-乙酰天冬氨酸（NAA）信号强度降低。在包括无残疾患者在内的所有 MS 亚组的半卵圆中心的 NAWM 中，均观察到 mI 与总肌酸（tCr）的比值升高（边缘均数±标准误差，健康对照组：0.78±0.04；EDSS 0-1：0.86±0.03[=0.02]；EDSS 1.5-3：0.95±0.04[<0.001]；EDSS≥3.5：0.94±0.04[=0.001]）。在有残疾的 MS 亚组中，发现 NAA 与 tCr 的比值降低，不仅在 NAWM（边缘均数±标准误差，健康对照组：1.46±0.04；EDSS 1.5-3：1.33±0.03[=0.03]；EDSS≥3.5：1.30±0.04[=0.01]），而且在 CGM（边缘均数±标准误差，健康对照组：1.42±0.05；EDSS≥3.5：1.23±0.05[=0.006]）中均如此。mI/NAA 与 EDSS 相关（半卵圆中心 NAWM：=0.47，<0.001；顶叶 NAWM：=0.43，=0.002；额叶 NAWM：=0.34，=0.01；额叶 CGM：=0.37，=0.004）。结论 在 7.0-T 时，磁共振波谱成象可在 T1 或 T2 加权 MRI 不可见的情况下进行体内可视化 MS 病理发现。正常表现白质和皮质灰质的代谢异常与残疾有关。©RSNA，2022 请参阅本期的编辑评论。
