Dzialowski Imanuel, Weber Johannes, Doerfler Arnd, Forsting Michael, von Kummer Rüdiger
Department of Neuroradiology, University of Dresden, Dresden, Germany.
J Neuroimaging. 2004 Jan;14(1):42-8.
To study whether computed tomography (CT) can measure the water content of early ischemic edema.
The authors obtained cranial CT in 5 groups of rats subjected to 1 hour (n = 8), 2 hours (n = 11), 3 hours (n = 13), 4 hours (n = 13), or 6 hours (n = 14) of right middle cerebral artery (MCA) occlusion. Immediately after CT, the authors removed the rats' brains and determined tissue water content by the dry-wet weight method. They correlated brain x-ray attenuation with brain tissue water content.
Mean brain tissue water content remained constant in the nonischemic left hemispheres at 77.9% +/- 0.6% and increased up to 79.3% +/- 1.0% in the right hemispheres after 6 hours of permanent right MCA occlusion. X-ray attenuation remained constant in the left hemispheres at 75.6 + 2.2 Hounsfield units (HU) and decreased to 71.7 +/- 3.4 HU in the right hemispheres after 6 hours of right MCA occlusion. The decrease in x-ray attenuation correlated significantly with the increase in ischemic brain tissue water content (y = 217.3 - 1.8x x; r = .55, P < .0001). That means that a 1% increase in hemispheric tissue water content causes a decrease in x-ray attenuation of 1.8 HU.
After MCA occlusion, immediate brain tissue net water uptake is associated with a decrease in x-ray attenuation. CT can monitor ischemic edema in an acute stroke.
研究计算机断层扫描（CT）能否测量早期缺血性水肿的含水量。
作者对5组大鼠进行了头颅CT扫描，这些大鼠分别经历了1小时（n = 8）、2小时（n = 11）、3小时（n = 13）、4小时（n = 13）或6小时（n = 14）的右侧大脑中动脉（MCA）闭塞。CT扫描后立即取出大鼠大脑，采用干湿重法测定组织含水量。他们将脑X线衰减与脑组织含水量进行关联分析。
在非缺血的左侧半球，平均脑组织含水量保持恒定，为77.9%±0.6%；在右侧大脑中动脉永久性闭塞6小时后，右侧半球含水量增加至79.3%±1.0%。左侧半球的X线衰减保持恒定，为75.6 + 2.2亨氏单位（HU）；右侧大脑中动脉闭塞6小时后，右侧半球的X线衰减降至71.7±3.4 HU。X线衰减的降低与缺血脑组织含水量的增加显著相关（y = 217.3 - 1.8x；r = 0.55，P < 0.0001）。这意味着半球组织含水量每增加1%，X线衰减就会降低1.8 HU。
大脑中动脉闭塞后，脑组织立即出现的净水分摄取与X线衰减降低有关。CT可用于监测急性卒中的缺血性水肿。
