Forouhandehpour Reihaneh, Bernier Michaël, Gilbert Guillaume, Butler Russell, Whittingstall Kevin, Van Houten Elijah
Department of Nuclear Medicine and Radiobiology, University of Sherbrooke, 3001, 12e Avenue Nord Sherbrooke, QC, J1H 5N4, Canada.
Martinos Center - MGH - Harvard Medical School, 149 Thirteenth Street, Charlestown, MA, USA, 02129.
Neuroimage Rep. 2021 May 26;1(2):100014. doi: 10.1016/j.ynirp.2021.100014. eCollection 2021 Jun.
We performed functional intrinsic Magnetic Resonance Elastography (fiMRE) as well as Time of Flight angiography and BOLD fMRI on 7 healthy human subjects to monitor shear stiffness and arterial dilation during periods of prolonged visual stimulation. FiMRE activation with increased stiffness was observed to occur almost equally within brain white and gray matter ( and , respectively), while activation with decreased stiffness was significantly ( ) more likely to occur in white matter than gray matter ( and , respectively). At the low mechanical activation and block design frequencies used in this intrinsic MRE (iMRE) approach, the aggregate stiffness change across the entire BOLD activation region was not significant. However, we observed significant reduction in shear stiffness (1.40 ± 0.15 to 0.68 ± 0.22 [kPa], p < 0.001) in areas adjacent to the Posterior Cerebral Artery, where vasodilation is evident, in the V1 region. In addition, we observed significant shear stiffness increase (1.29 ± 0.12 to 0.62 ± 0.16 [kPa], p < 0.001) in areas adjacent to the Middle Temporal or V5 region of the visual cortex. These results show that iMRE can measure intrinsic cerebro-mechanical reactions due to visual stimulation as well as the differential physiological response detected in distinct regions of the visual cortex.
我们对7名健康人类受试者进行了功能性磁共振弹性成像（fiMRE）以及飞行时间血管造影和血氧水平依赖性功能磁共振成像（BOLD fMRI），以监测长时间视觉刺激期间的剪切刚度和动脉扩张情况。观察到刚度增加时的FiMRE激活在脑白质和灰质中几乎同等程度地发生（分别为 和 ），而刚度降低时的激活在白质中比灰质中显著更易发生（分别为 和 ）。在这种本征磁共振弹性成像（iMRE）方法中使用的低机械激活和阻断设计频率下，整个BOLD激活区域的总刚度变化不显著。然而，我们观察到在大脑后动脉附近、V1区域有明显血管扩张的区域，剪切刚度显著降低（从1.40±0.15降至0.68±0.22[kPa]，p<0.001）。此外，我们观察到在视觉皮层颞中区或V5区附近区域，剪切刚度显著增加（从1.29±0.12升至0.62±0.16[kPa]，p<0.001）。这些结果表明，iMRE能够测量视觉刺激引起的内在脑机械反应以及在视觉皮层不同区域检测到的差异生理反应。
