How to monitor cerebral blood flow or specifically how to monitor cerebral blood flow in rat mice?

There are not many methods for real-time monitoring of animal cerebral blood flow. Here we focus on the real-time evaluation method of laser perfusion and laser speckle for blood perfusion.

First, laser Doppler blood flow meter: There are two types of laser Doppler blood flow meter on the market: contact and non-contact, can be applied to cerebral blood flow assessment.

a) The contact laser Doppler flowmeter has a variety of probes and is an essential instrument for the evaluation of cerebral ischemia model. The Swedish perimed 407 probe is taken as an example to explain:

1. The first is to determine the location of the monitoring: this depends on the strain and body weight of the experimental animal, as well as the type of ischemic model. If the model of middle cerebral artery ischemia is performed, the position is usually a few millimeters outside the midline of the ipsilateral sacral sac, and the data published in other papers cannot be mechanically copied. (I forgot to cut the skin and clean the fascia of the skull surface. The penetration depth of the laser Doppler is about 1mm. The presence of skin and hair will completely block the signal. LDF has no ability to beat the mountain.)

2. The depth of anesthesia, the choice of anesthetic, and other surgical procedures may affect the state of the animal (note that it affects the state of the animal, not affecting the monitoring of the instrument). If high quality data is required, the experimental conditions need to be standardized, and Animal blood pressure monitoring (blood pressure can significantly affect microcirculation blood perfusion)

3. Secure the probe to the skull.

4. The blood flow before ischemia, ischemia moment, and reperfusion after ischemia should be continuously monitored. Because of the spatial difference of microcirculatory vascular bed distribution, intermittent blood flow before and after ischemia can reduce the credibility of experimental data.

b) Non-contact laser Doppler is also called laser Doppler perfusion imager. As its name suggests, it can express blood perfusion in the form of images. This is like the scene we see when we take pictures. It takes pictures of the blood flowing in the blood vessels. The following figure shows the perfusion images of pre-ischemic and post-ischemic rats in rats monitored by the Perimed PIM3 laser Doppler perfusion imager.

Second, laser speckle blood perfusion video system: the birth of laser speckle blood flow monitoring video system makes it impossible to monitor the micro-circulation phenomenon, blood flow changes like a movie. The figure below shows the Pericam PSI laser speckle blood perfusion video system of the Swedish perimed company, and data analysis can be performed for each region and blood perfusion at a specific time.

The monitoring of the microcirculation can not be eager for quick success. Some students put the probe in the monitoring position and read the data to say how much the microcirculation blood perfusion is. The two data are different, and the instrument is inaccurate. This is In the wrong case, the microcirculation itself has spatial differences and time dynamics, which need to be evaluated by objective means and rigorous experimental design. Detailed methods and more examples can be found at or