Vedaei Faezeh, Alizadeh Mahdi, Romo Victor, Mohamed Feroze B, Wu Chengyuan
Department of Radiology, Jefferson Integrated Magnetic Resonance Imaging Center, Thomas Jefferson University, Philadelphia, PA, United States.
Department of Neurological Surgery, Vickie and Jack Farber Institute for Neuroscience, Thomas Jefferson University, Philadelphia, PA, United States.
Front Neurosci. 2022 Aug 16;16:937172. doi: 10.3389/fnins.2022.937172. eCollection 2022.
Resting-state functional magnetic resonance imaging (rs-fMRI) has been known as a powerful tool in neuroscience. However, exploring the test-retest reliability of the metrics derived from the rs-fMRI BOLD signal is essential, particularly in the studies of patients with neurological disorders. Here, two factors, namely, the effect of anesthesia and scan length, have been estimated on the reliability of rs-fMRI measurements. A total of nine patients with drug-resistant epilepsy (DRE) requiring interstitial thermal therapy (LITT) were scanned in two states. The first scan was performed in an awake state before surgery on the same patient. The second scan was performed 2 weeks later under general anesthesia necessary for LITT surgery. At each state, two rs-fMRI sessions were obtained that each one lasted 15 min, and the effect of scan length was evaluated. Voxel-wise rs-fMRI metrics, including the amplitude of low-frequency fluctuation (ALFF), the fractional amplitude of low-frequency fluctuation (fALFF), functional connectivity (FC), and regional homogeneity (ReHo), were measured. Intraclass correlation coefficient (ICC) was calculated to estimate the reliability of the measurements in two states of awake and under anesthesia. Overall, it appeared that the reliability of rs-fMRI metrics improved under anesthesia. From the 15-min data, we found mean ICC values in awake state including 0.81, 0.51, 0.65, and 0.84 for ALFF, fALFF, FC, and ReHo, respectively, as well as 0.80, 0.59, 0.83, and 0.88 for ALFF, fALFF, FC, and ReHo, respectively, under anesthesia. Additionally, our findings revealed that reliability increases as the function of scan length. We showed that the optimized scan length to achieve less variability of rs-fMRI measurements was 3.1-7.5 min shorter in an anesthetized, compared to a wakeful state.
静息态功能磁共振成像（rs-fMRI）在神经科学领域一直被视为一种强大的工具。然而，探究从rs-fMRI血氧水平依赖（BOLD）信号得出的指标的重测信度至关重要，尤其是在神经系统疾病患者的研究中。在此，已对麻醉效果和扫描时长这两个因素对rs-fMRI测量信度的影响进行了评估。共有9例需要进行间质热疗（LITT）的耐药性癫痫（DRE）患者在两种状态下接受了扫描。第一次扫描是在同一患者手术前的清醒状态下进行的。第二次扫描是在LITT手术所需的全身麻醉下于2周后进行的。在每种状态下，均获取了两个时长各为15分钟的rs-fMRI扫描时段，并评估了扫描时长的影响。测量了体素水平的rs-fMRI指标，包括低频振幅（ALFF）、低频振幅分数（fALFF）、功能连接（FC）和局部一致性（ReHo）。计算组内相关系数（ICC）以评估清醒和麻醉两种状态下测量的信度。总体而言，rs-fMRI指标的信度在麻醉状态下有所提高。从15分钟的数据来看，我们发现清醒状态下ALFF、fALFF、FC和ReHo的平均ICC值分别为0.81、0.51、0.65和0.84，麻醉状态下ALFF、fALFF、FC和ReHo的平均ICC值分别为为0.80、0.59、0.83和0.88。此外，我们的研究结果表明，信度随扫描时长的增加而提高。我们发现，与清醒状态相比，麻醉状态下实现rs-fMRI测量变异性更小的优化扫描时长要短3.1 - 7.5分钟。
