Bhattacharyya Pallab K, Phillips Micheal D, Stone Lael A, Lowe Mark J
Imaging Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA; Radiology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Ave, Cleveland, OH 44195, USA.
Imaging Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA.
Magn Reson Imaging. 2017 Oct;42:123-129. doi: 10.1016/j.mri.2017.06.009. Epub 2017 Jun 17.
To explore the relative robustness of functional MRI (fMRI) activation volume and blood oxygen level-dependent (BOLD) signal change as fMRI metric, and to study the effect of relative robustness on the correlation between fMRI activation and cortical gamma amino butyric acid (GABA) in healthy controls and patients with multiple sclerosis (MS).
fMRI data were acquired from healthy controls and patients with MS, with the subjects peforming self paced bilateral finger tapping in block design. GABA spectroscopy was performed with voxel placed on the area of maximum activation during fMRI. Activation volume and BOLD signal changes at primary motor cortex (M1), as well as GABA concentration were calculated for each patient.
Activation volume correlated with BOLD signal change in healthy controls, but no such correlation was observed in patients with MS. This difference was likely the result of higher intersubject noise variance in the patient population. GABA concentration correlated with M1 activation volume in patients but not in controls, and did not correlate with any fMRI metric in patients or controls.
Our data suggest that activation volume is a more robust measure than BOLD signal change in a group with high intersubject noise variance as in patients with MS. Additionally, this study demonstrated difference in correlation behavior between GABA concentration and the 2 fMRI metrics in patients with MS, suggesting that GABA - activation volume correlation is more appropriate measure in the patient group.
探讨功能磁共振成像（fMRI）激活体积和血氧水平依赖（BOLD）信号变化作为fMRI指标的相对稳健性，并研究相对稳健性对健康对照者和多发性硬化症（MS）患者fMRI激活与皮质γ-氨基丁酸（GABA）之间相关性的影响。
从健康对照者和MS患者获取fMRI数据，受试者在组块设计中进行自我节奏的双侧手指敲击。在fMRI期间，将体素放置在最大激活区域进行GABA光谱分析。计算每位患者初级运动皮层（M1）的激活体积和BOLD信号变化以及GABA浓度。
健康对照者中激活体积与BOLD信号变化相关，但MS患者中未观察到这种相关性。这种差异可能是患者群体中受试者间噪声方差较高的结果。GABA浓度在患者中与M1激活体积相关，而在对照者中不相关，并且在患者或对照者中与任何fMRI指标均不相关。
我们的数据表明，在像MS患者这样受试者间噪声方差较高的群体中，激活体积是比BOLD信号变化更稳健的测量指标。此外，本研究证明了MS患者中GABA浓度与两种fMRI指标之间相关性行为的差异，表明GABA-激活体积相关性在患者组中是更合适地测量指标。
