Department of Radiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, 20892, USA.
Brain Imaging Behav. 2018 Jun;12(3):848-859. doi: 10.1007/s11682-017-9742-7.
Functional connectivity density mapping (FCDM) is a newly developed data-driven technique that quantifies the number of local and global functional connections for each voxel in the brain. In this study, we evaluated reproducibility, sensitivity, and specificity of both local functional connectivity density (lFCD) and global functional connectivity density (gFCD). We compared these metrics using the human connectome project (HCP) compatible high-resolution (2 mm isotropic, TR = 0.8 s) multiband (MB), and more typical, lower resolution (3.5 mm isotropic, TR = 2.0 s) single-band (SB) resting state functional MRI (rs-fMRI) acquisitions. Furthermore, in order to be more clinically feasible, only rs-fMRI scans that lasted seven minutes were tested. Subjects were scanned twice within a two-week span. We found sensitivity and specificity increased and reproducibility either increased or did not change for the MB compared to the SB acquisitions. The MB scans also showed improved gray matter/white matter contrast compared to the SB scans. The lFCD and gFCD patterns were similar across MB and SB scans and confined predominantly to gray matter. We also observed a strong spatial correlation of FCD between MB and SB scans indicating the two acquisitions provide similar information. These findings indicate high-resolution MB acquisitions improve the quality of FCD data, and seven minute rs-fMRI scan can provide robust FCD measurements.
功能连接密度图（FC Density Mapping，FCDM）是一种新开发的数据驱动技术，可量化大脑每个体素的局部和全局功能连接数量。本研究评估了局部功能连接密度（Local Functional Connectivity Density，lFCD）和全局功能连接密度（Global Functional Connectivity Density，gFCD）的可重复性、灵敏度和特异性。我们使用兼容人类连接组计划（Human Connectome Project，HCP）的高分辨率（2mm 各向同性，TR=0.8s）多频带（Multiband，MB）和更典型的低分辨率（3.5mm 各向同性，TR=2.0s）单频带（Single-band，SB）静息态功能磁共振成像（Resting-state Functional Magnetic Resonance Imaging，rs-fMRI）采集来比较这些指标。此外，为了更具临床可行性，仅测试了持续七分钟的 rs-fMRI 扫描。被试在两周内接受两次扫描。我们发现，与 SB 采集相比，MB 采集的灵敏度和特异性提高，可重复性要么提高，要么不变。与 SB 扫描相比，MB 扫描还显示出更好的灰质/白质对比。MB 和 SB 扫描之间的 lFCD 和 gFCD 模式相似，主要局限于灰质。我们还观察到 FCD 在 MB 和 SB 扫描之间具有很强的空间相关性，表明这两种采集提供了相似的信息。这些发现表明，高分辨率 MB 采集可提高 FCD 数据的质量，而持续七分钟的 rs-fMRI 扫描可提供可靠的 FCD 测量。
