Department of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
IEEE Trans Biomed Eng. 2010 May;57(5):1152-7. doi: 10.1109/TBME.2009.2037434. Epub 2010 Feb 5.
Laser speckle imaging (LSI) has been widely used for in vivo detecting cerebral blood flow (CBF) under various physiological and pathological conditions. So far, nearly all literature on in vivo LSI does not consider the influence of disturbances due to respiration and/or heart beating of animals. In this paper, we analyze how such physiologic motions affect the spatial resolution of the conventional laser speckle contrast analysis (LASCA). We propose a registered laser speckle contrast analysis (rLASCA) method which first registers raw speckle images with a 3 x 3 convolution kernel, normalized correlation metric and cubic B-spline interpolator, and then constructs the contrast image for CBF. rLASCA not only significantly improves the distinguishability of small vessels, but also efficiently suppresses the noises induced by respiration and/or heart beating. In an application of imaging the angiogenesis of rat's brain tumor, rLASCA outperformed the conventional LASCA in providing a much higher resolution for new small vessels. As a processing method for LSI, rLASCA can be directly applied to other LSI experiments where the disturbances from different sources (like respiration, heart beating) exist.
激光散斑成像（LSI）已广泛应用于各种生理和病理条件下的活体脑血流（CBF）检测。到目前为止，几乎所有关于活体 LSI 的文献都没有考虑到动物呼吸和/或心跳引起的干扰的影响。在本文中，我们分析了这些生理运动如何影响传统激光散斑对比分析（LASCA）的空间分辨率。我们提出了一种注册激光散斑对比分析（rLASCA）方法，该方法首先使用 3x3 卷积核、归一化相关度量和三次 B 样条插值器对原始散斑图像进行配准，然后构建 CBF 的对比度图像。rLASCA 不仅显著提高了小血管的可分辨性，而且有效地抑制了呼吸和/或心跳引起的噪声。在对大鼠脑肿瘤血管生成的成像应用中，rLASCA 在提供新的小血管的更高分辨率方面优于传统的 LASCA。作为 LSI 的处理方法，rLASCA 可以直接应用于存在来自不同来源（如呼吸、心跳）干扰的其他 LSI 实验。
