Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02129, USA.
Transl Stroke Res. 2010 Mar;1(1):65-70. doi: 10.1007/s12975-009-0009-5. Epub 2010 Jan 20.
Edema is an important part of the pathophysiology of stroke. However, it remains unclear how brain swelling may influence the progression and measurement of infarction after cerebral ischemia. Initial studies in a mouse model of transient middle cerebral artery occlusion demonstrated that infarction grew from 24 to 72 h after stroke onset. Comparison of 24-h versus 72-h brains suggested that tissue swelling developed in both infarcted and non-infarcted ipsilateral regions. Volumes of infarction differed, depending on the method of calculation: direct, indirect, or normalized. A simple first-order model was constructed dividing total brain into three subsets, comprising normal contralateral tissue, non-infarcted ipsilateral tissue, and infarcted ipsilateral tissue. Each subset was then defined as a ratio of original volumes plus additional swollen volumes. By changing the relative portion of swelling assigned to infarct versus non-infarct, our model demonstrated that direct, indirect, and normalized calculations led to different thresholds for matching absolute infarct volumes. In this proof-of-principle study, we described a mathematical model to simulate the distribution of brain swelling and infarct development over time. Our findings suggest that accurate quantitation of infarct volumes depends on relative distributions of edema that may occur in both infarcted as well as non-infarcted brain.
脑水肿是中风病理生理学的重要组成部分。然而，目前尚不清楚脑肿胀如何影响脑缺血后梗死的进展和测量。在短暂性大脑中动脉闭塞的小鼠模型中的初步研究表明，梗死在中风发作后 24 至 72 小时之间增大。与 24 小时相比，24 小时和 72 小时的大脑比较表明，在梗死和非梗死同侧区域均出现组织肿胀。根据计算方法的不同，梗死体积有所不同：直接法、间接法或归一化法。构建了一个简单的一阶模型，将整个大脑分为三个子集，包括正常的对侧组织、非梗死同侧组织和梗死同侧组织。然后，每个子集被定义为原始体积加上额外肿胀体积的比值。通过改变分配给梗死与非梗死的肿胀的相对部分，我们的模型表明，直接法、间接法和归一化法导致匹配绝对梗死体积的不同阈值。在这项原理验证研究中，我们描述了一个数学模型来模拟脑水肿和梗死随时间的分布和发展。我们的研究结果表明，梗死体积的准确定量取决于可能在梗死和非梗死的脑区中都发生的水肿的相对分布。
