Agarwal Shruti, Lu Hanzhang, Pillai Jay J
1 Division of Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine , Baltimore, Maryland.
2 Division of MR Research, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine , Baltimore, Maryland.
Brain Connect. 2017 Aug;7(6):382-389. doi: 10.1089/brain.2016.0480.
The aim of this study was to explore whether the phenomenon of brain tumor-related neurovascular uncoupling (NVU) in resting-state blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) (rsfMRI) may also affect the resting-state fMRI (rsfMRI) frequency domain metrics the amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF). Twelve de novo brain tumor patients, who underwent clinical fMRI examinations, including task-based fMRI (tbfMRI) and rsfMRI, were included in this Institutional Review Board-approved study. Each patient displayed decreased/absent tbfMRI activation in the primary ipsilesional (IL) sensorimotor cortex in the absence of a corresponding motor deficit or suboptimal task performance, consistent with NVU. Z-score maps for the motor tasks were obtained from general linear model analysis (reflecting motor activation vs. rest). Seed-based correlation analysis (SCA) maps of sensorimotor network, ALFF, and fALFF were calculated from rsfMRI data. Precentral and postcentral gyri in contralesional (CL) and IL hemispheres were parcellated using an automated anatomical labeling template for each patient. Region of interest (ROI) analysis was performed on four maps: tbfMRI, SCA, ALFF, and fALFF. Voxel values in the CL and IL ROIs of each map were divided by the corresponding global mean of ALFF and fALFF in the cortical brain tissue. Group analysis revealed significantly decreased IL ALFF (p = 0.02) and fALFF (p = 0.03) metrics compared with CL ROIs, consistent with similar findings of significantly decreased IL BOLD signal for tbfMRI (p = 0.0005) and SCA maps (p = 0.0004). The frequency domain metrics ALFF and fALFF may be markers of lesion-induced NVU in rsfMRI similar to previously reported alterations in tbfMRI activation and SCA-derived resting-state functional connectivity maps.
本研究的目的是探讨在静息态血氧水平依赖性功能磁共振成像（BOLD fMRI，即rsfMRI）中脑肿瘤相关神经血管解偶联（NVU）现象是否也会影响静息态功能磁共振成像（rsfMRI）的频域指标低频振幅（ALFF）和分数低频振幅（fALFF）。12例初发脑肿瘤患者接受了包括任务态功能磁共振成像（tbfMRI）和rsfMRI在内的临床功能磁共振成像检查，本研究经机构审查委员会批准。在没有相应运动功能障碍或任务表现欠佳的情况下，每位患者在患侧（IL）初级感觉运动皮层的tbfMRI激活均降低/缺失，这与NVU一致。运动任务的Z分数图通过一般线性模型分析获得（反映运动激活与静息状态）。基于种子点的感觉运动网络、ALFF和fALFF的相关分析（SCA）图由rsfMRI数据计算得出。使用自动解剖标记模板对每位患者的对侧（CL）和患侧半球的中央前回和中央后回进行分割。对tbfMRI、SCA、ALFF和fALFF四张图进行感兴趣区（ROI）分析。每张图的CL和IL ROI中的体素值除以皮质脑组织中ALFF和fALFF的相应全局平均值。组间分析显示，与CL ROI相比，IL的ALFF（p = 0.02）和fALFF（p = 0.03）指标显著降低，这与tbfMRI（p = 0.0005）和SCA图（p = 0.0004）中IL的BOLD信号显著降低的类似发现一致。频域指标ALFF和fALFF可能是rsfMRI中病变诱导的NVU的标志物，类似于先前报道的tbfMRI激活和SCA衍生的静息态功能连接图的改变。
