Pearce R A, Adams J M
Stroke. 1982 May-Jun;13(3):347-55. doi: 10.1161/01.str.13.3.347.
Although experimental evidence now indicates that diffusion of hydrogen can influence the measured clearance curves from which local blood flow is inferred, its exact role has not yet been well defined. For this reason we have developed a theoretical treatment of the effects of diffusion near a boundary separating regions of inhomogeneous perfusion (e.g. the gray-matter interface), and reexamined the appropriateness of the currently used bi-exponential model. Using our model, we confirmed empirical estimates of important diffusion effects up to approximately 2 mm from an inhomogeneity, and further refined the concept of spatial resolution. We also showed that fitting data to bi-exponential curves may be incorrect and lead to inaccurate results. We conclude from these studies that diffusion does indeed have an important effect on the clearance curves measured near an inhomogeneity.
尽管目前的实验证据表明，氢的扩散会影响用于推断局部血流的测量清除曲线，但其确切作用尚未得到明确界定。因此，我们针对非均匀灌注区域（如灰质界面）边界附近的扩散效应开展了理论研究，并重新审视了当前使用的双指数模型的适用性。利用我们的模型，我们证实了在距不均匀性约2毫米范围内重要扩散效应的经验估计，并进一步完善了空间分辨率的概念。我们还表明，将数据拟合为双指数曲线可能是不正确的，并会导致不准确的结果。我们从这些研究中得出结论，扩散确实对在不均匀性附近测得的清除曲线有重要影响。
