SY时长：一周
血流灌注成像仪 PeriCam PSI 血流成像仪基于激光散斑对比分析（Laser Speckle Contrast Analysis / LASCA）技术，
该技术[1-6]能够使微循环血流灌注瞬间变化肉眼可见。该成像技术分辨率高，采样频率快！
目标受到激光束照射时，反射后的激光形成随机干扰图像（包括亮区和暗区），该图像称为激光散斑图。如果被测目标静止，激光散斑图也保持不变。如果被测物体发生移动，例如组织中的红细胞运动，则激光散斑图会随之波动。 CCD 激光探测相机记录激光散斑图的上述变化。
激光散斑图的变化速度取决于监测区域内目标移动速度；目标移动速度越快，散斑图变化越明显。散斑变化速度以散斑对比度量化，而对比度与血流相关；这就是 LASCA技术用于血流灌注量评估的工作原理。散斑对比度定义为强度标准差与强度平均值的比值。监测区域内运动越厉害，散斑波动会增加，强度标准差会降 低，因此散斑对比度较低。相反，如果没有运动，散斑波动会减少，强度标准差会升高，因此散斑对比度较高。而强度平均值保持不变。
下图为该仪器的激光散斑血流灌注图像。
激光多普勒血流仪 PeriFlux 5000 
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6. Excellent reproducibility of laser speckle contrast imaging to assess skin microvascular reactivity. Roustit M. Microvasc Res. 2010
