Department of Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, 6431 Fannin St, MSB 2.100, Houston, TX 77030, USA.
Radiology. 2012 Jun;263(3):819-27. doi: 10.1148/radiol.12111986. Epub 2012 Mar 13.
To identify intraorbital and intracranial abnormalities in astronauts previously exposed to microgravity by using quantitative and qualitative magnetic resonance (MR) techniques.
The institutional review board approved this HIPAA-compliant, retrospective review and waived the requirement for informed consent. Twenty-seven astronauts (mean age ± standard deviation, 48 years ± 4.5) underwent 3-T MR imaging with use of thin-section, three-dimensional, axial T2-weighted orbital and conventional brain sequences. Eight astronauts underwent repeat imaging after an additional mission in space. Optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) were quantified in the retrolaminar optic nerve. OND and central optic nerve T2 hyperintensity were quantified at mid orbit. Qualitative analysis of the optic nerve sheath, optic disc, posterior globe, and pituitary gland morphology was performed and correlated for association with intracranial evidence of hydrocephalus, vasogenic edema, central venous thrombosis, and/or mass lesion. Statistical analyses included the paired t test, Mann-Whitney nonparametric test for group comparisons, Cronbach α coefficient for reproducibility, and Pearson correlation coefficient.
All astronauts had previous exposure to microgravity and, thus, control data were not available for comparison. The ONSD and OND ranged from 4.7 to 10.8 mm (mean, 6.2 mm ± 1.1) and from 2.4 to 4.5 mm (mean, 3.0 mm ± 0.5), respectively. Posterior globe flattening was seen in seven of the 27 astronauts (26%), optic nerve protrusion in four (15%), and moderate concavity of the pituitary dome with posterior stalk deviation in three (11%) without additional intracranial abnormalities. Retrolaminar OND increased linearly relative to ONSD (r = 0.797, Pearson correlation). A central area of T2 hyperintensity was identifiable in 26 of the 27 astronauts (96%) and increased in diameter in association with kinking of the optic nerve sheath.
Exposure to microgravity can result in a spectrum of intraorbital and intracranial findings similar to those in idiopathic intracranial hypertension.
使用定量和定性磁共振（MR）技术，确定先前暴露于微重力环境下的宇航员的眶内和颅内异常。
该机构审查委员会批准了这项符合 HIPAA 规定的回顾性研究，并豁免了知情同意书的要求。27 名宇航员（平均年龄±标准差，48 岁±4.5 岁）接受了 3-T MR 成像检查，使用了薄层、三维、轴位 T2 加权眶内和常规脑序列。8 名宇航员在额外的太空任务后进行了重复成像。在视神经管内测量视神经鞘直径（ONSD）和视神经直径（OND）。在眶中部测量视神经的直径和中央视神经 T2 高信号。对视神经鞘、视盘、后球和垂体形态进行定性分析，并与颅内脑积水、血管源性水肿、中央静脉血栓形成和/或肿块病变的证据相关联。统计分析包括配对 t 检验、组间 Mann-Whitney 非参数检验、重复性 Cronbach α 系数和 Pearson 相关系数。
所有宇航员都曾暴露于微重力环境下，因此，没有对照数据可供比较。ONSD 和 OND 的范围分别为 4.7 至 10.8 毫米（平均值，6.2 毫米±1.1 毫米）和 2.4 至 4.5 毫米（平均值，3.0 毫米±0.5 毫米）。27 名宇航员中有 7 名（26%）出现后球扁平，4 名（15%）出现视神经突出，3 名（11%）出现垂体窝中度凹陷伴后柄偏斜，无其他颅内异常。视神经管内 OND 与 ONSD 呈线性增加（r=0.797，Pearson 相关）。27 名宇航员中有 26 名（96%）可识别出中央 T2 高信号区，并且随着视神经鞘的扭曲，该区域的直径增大。
暴露于微重力环境可导致一系列眶内和颅内表现，类似于特发性颅内高压。
