Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Ishikawa, Japan.
Radiological center, University of Fukui Hospital, Fukui, Japan.
J Magn Reson Imaging. 2018 Feb;47(2):565-571. doi: 10.1002/jmri.25781. Epub 2017 Jun 3.
To quantify the acute effect of the head-down tilt (HDT) posture on intracranial hemodynamics and hydrodynamics.
We evaluated the intracranial physiological parameters, blood flow-related parameters, and brain morphology in the HDT (-6° and -12°) and the horizontal supine (HS) positions. Seven and 15 healthy subjects were scanned for each position using 3.0 T magnetic resonance imaging system. The peak-to-peak intracranial volume change, the peak-to-peak cerebrospinal fluid (CSF) pressure gradient (PG ), and the intracranial compliance index were calculated from the blood and CSF flow determined using a cine phase-contrast technique. The brain volumetry was conducted using SPM12. The measurements were compared using the Wilcoxon signed-rank test or a paired t-test.
No measurements changed in the -6° HDT. The PG and venous outflow of the internal jugular veins (IJVs) in the -12° HDT were significantly increased compared to the HS (P < 0.001 and P = 0.025, respectively). The cross-sectional areas of the IJVs were significantly larger (P < 0.001), and the maximum, minimum, and mean blood flow velocity of the IJVs were significantly decreased (P = 0.003, < 0.001, and = 0.001, respectively) in the -12° HDT. The mean blood flow velocities of the internal carotid arteries were decreased (P = 0.023). Neither position affected the brain volume.
Pressure gradient and venous outflow were increased in accordance with the elevation of the intracranial pressure as an acute effect of the HDT. However, the CSF was not constantly shifted from the spinal canal to the cranium.
2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:565-571.
定量研究头低位倾斜（HDT）对颅内血液动力学和流体动力学的急性影响。
我们评估了颅内生理参数、血流相关参数和 HDT（-6°和-12°）及水平仰卧位（HS）下的脑形态。使用 3.0 T 磁共振成像系统对每位受试者的每个体位分别进行 7 次和 15 次扫描。使用电影相位对比技术确定血流和脑脊液（CSF）后，计算颅内容积变化峰峰值、CSF 压力梯度（PG）峰峰值和颅内顺应性指数。使用 SPM12 进行脑容量测量。采用 Wilcoxon 符号秩检验或配对 t 检验进行比较。
-6°HDT 下无测量值发生变化。与 HS 相比，-12°HDT 下 PG 和颈内静脉（IJVs）静脉流出明显增加（P < 0.001 和 P = 0.025）。IJVs 横截面积明显增大（P < 0.001），最大、最小和平均 IJVs 血流速度明显降低（P = 0.003，< 0.001 和 = 0.001），-12°HDT 下。颈内动脉平均血流速度降低（P = 0.023）。两种体位均不影响脑容量。
HDT 的急性作用使颅内压升高，导致 PG 和静脉流出增加，但 CSF 并未持续从椎管转移至颅腔。
2 级技术功效：第 1 阶段。磁共振成像杂志 2018；47:565-571.
